capacity enhancing techniques and multi layer systems

CHAPTER 2 CHAPTER 3 CHAPTER 4 CHAPTER 5CHAPTER 1

TRAINING MANUAL

COURSECODESYS12

COURSE TITLE CAPACITY ENHANCING TECHNIQUES ANDMULTILAYER SYSTEMS – INC HR

FOR TRAINING PURPOSES ONLY – THIS MANUAL WILL NOT BE UPDATED

GSM SOFTWARE RELEASE 7

VERSION 1 REV 1

TR

AIN

ING

MA

NU

AL

COURSECODESYS12

GS

M S

OF

TW

AR

E R

ELE

AS

E 7

FOR TRAININGPURPOSES ONLY

– THIS MANUALWILL NOT BE

UPDATED

VE

RS

ION

1 RE

V 1

CO

UR

SE

TIT

LE C

AP

AC

ITY

EN

HA

NC

ING

TE

CH

NIQ

UE

S A

ND

MU

LTILA

YE

RS

YS

TE

MS

– INC

HR

�MOTOROLA LTD. 2004Course Code SYS12: Course title Capacity Enhancing Techniques and Multilayer Systems – inc HR


i

GSM

Software Release GSR7

Course Code SYS12Course title Capacity Enhancing

Techniques and MultilayerSystems – inc HR

� Motorola 2002All Rights ReservedPrinted in the UK.

Version 1 Rev 0



ii

Copyrights, notices and trademarks

CopyrightsThe Motorola products described in this document may include copyrighted Motorola computerprograms stored in semiconductor memories or other media. Laws in the United States and othercountries preserve for Motorola certain exclusive rights for copyright computer programs, including theexclusive right to copy or reproduce in any form the copyright computer program. Accordingly, anycopyright Motorola computer programs contained in the Motorola products described in this documentmay not be copied or reproduced in any manner without the express written permission of Motorola.Furthermore, the purchase of Motorola products shall not be deemed to grant either directly or byimplication, estoppel or otherwise, any license under the copyrights, patents or patent applications ofMotorola, except for the rights that arise by operation of law in the sale of a product.

RestrictionsThe software described in this document is the property of Motorola. It is furnished under a licenseagreement and may be used and/or disclosed only in accordance with the terms of the agreement.Software and documentation are copyright materials. Making unauthorized copies is prohibited bylaw. No part of the software or documentation may be reproduced, transmitted, transcribed, storedin a retrieval system, or translated into any language or computer language, in any form or by anymeans, without prior written permission of Motorola.

AccuracyWhile reasonable efforts have been made to assure the accuracy of this document, Motorolaassumes no liability resulting from any inaccuracies or omissions in this document, or from the useof the information obtained herein. Motorola reserves the right to make changes to any productsdescribed herein to improve reliability, function, or design, and reserves the right to revise thisdocument and to make changes from time to time in content hereof with no obligation to notify anyperson of revisions or changes. Motorola does not assume any liability arising out of the applicationor use of any product or circuit described herein; neither does it convey license under its patentrights of others.

Trademarks

and MOTOROLA are registered trademarks of Motorola Inc. Intelligence Everywhere, M-Cell and Taskfinder are trademarks of Motorola Inc.All other brands and corporate names are trademarks of their respective owners.

.

.

.

Version 1 Rev 0



iii

Contents

General information 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reporting safety issues 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Warnings and cautions 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General warnings 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General cautions 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Devices sensitive to static 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 1Introduction to Capacity Enhancing Techniques and Multilayer Systems 1–1

Introduction to Capacity Enhancing Techniques and Multilayer Systems 1–3. . . . . . . . . . . . Objectives 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Considerations 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Spectrum 1–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Re–use Pattern 1–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frequencies 1–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sectorisation 1–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 x 3 Frequency Reuse Pattern 1–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sectorisation 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 x 6 Frequency Reuse Pattern 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cell splitting 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saturation point 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cell size 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Hopping 1–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Microcellular Techniques 1–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microcellular Systems 1–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Motorola PBGT Algorithms 1–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Microcellular Techniques, cont., 1–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adaptive Handovers 1–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multiband Environment 1–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Half Rate 1–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Multi–Rate (AMR) 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AMR Full – Rate Channel Mode 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Full Rate Link Adaptation 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AMR Half – Rate Channel Mode 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Half Rate Link Adaptation 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Concentric Cells 1–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Purpose of Concentric Cells 1–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction of carriers on different frequency bands 1–28. . . . . . . . . . . . . . . . . . . . . . . Coincident Multiband 1–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single BCCH for Dual Band Cells 1–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Directed Retry and Congestion Relief 1–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Directed retry 1–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Congestion relief 1–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



iv

Extended Range Cells 1–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 2Frequency Hopping 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Frequency Hopping 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Objectives 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multipath Fading 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interference 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Hopping Basics 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Base Band Frequency Hopping (BBH) 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Synthesiser Frequency Hopping (SFH) 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Hopping Enhancements 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . chg_hop_params 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Redefinition 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Hopping to Enhance Network Capacity 2–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Reuse Patterns 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Loading Factor 2–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aggressive Frequency Reuse in SFH System 2–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Planning Guidelines for SFH 2–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aggressive Frequency Reuse in SFH System 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planning Guidelines for SFH using 1x3 Frequency Reuse 2–24. . . . . . . . . . . . . . . . . . . . . . . . SFH 1x3 Frequency Reuse Example 2–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planning Guidelines for SFH using 1x1 Frequency Reuse 2–26. . . . . . . . . . . . . . . . . . . . . . . . SFH 1x1 Frequency Reuse Example 2–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparisons between 1x3 and 1x1 Frequency Reuse Patterns 2–29. . . . . . . . . . . . . . . . . . .

Frequency Reuse in Baseband Hopping 2–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Progressive Reuse Patterns 2–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Homogeneous Reuse Pattarn 2–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Planning Rules for BBH 2–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Capacity Gains for SFH and BBH 2–33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 2–33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Optimisation after Frequency Hopping Implementation 2–35. . . . . . . . . . . . . . . . . . . . . . . . . . .

Neighbour List Optimisation 2–37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How to Detect 2–37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Database Optimisation 2–39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Control 2–39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recommendations for hopping systems 2–39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handovers 2–39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RXQUAL Hopping parameters 2–39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RF Hardware Optimisation 2–41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How to detect 2–41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Plan 2–43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 3Deployment of Microcellular 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deployment of Microcellular 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Objectives 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



v

Introduction to Microcellular 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What are microcells? 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The street canyon 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RF considerations 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microcell applications 3–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multi–Layered System 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Deployment Strategies 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combined cell handovers 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hotspots 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hotspots handovers 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handovers to/from hotspot cells 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handovers to the hotspot cell 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Controlling Handovers in Hotspots 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fast moving MSs entering a hotspot 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MSs leaving a hotspot 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Idle Mobile Behaviour 3–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Association of mobiles to micro/macro layer 3–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Methods of controlling reselection into a cell 3–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cell reselection C2 3–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cell reselection C2 – Continued 3–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Selective cell–bar on microcells 3–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C2 reselection exercise 3–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Effects of Broadcasting Separate BA Lists 3–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Broadcasting separate BA lists 3–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Method 1: (see table opposite) 3–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Method 2: (see table opposite) 3–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The layered Approach 3–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

BA Lists Exercise 3–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 4Microcellular Database 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Microcellular Database 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives 4–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Microcellular Handover Criteria 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Macro%Macro 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Macro%Micro 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Micro%Micro 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Micro%Macro 4–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Current Motorola Handover Decision Algorithms 4–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

hreqave and hreqt 4–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pointing Averaging Mechanisms to Decision Processes 4–10. . . . . . . . . . . . . . . . . . . . . . . . . .

use_neighbor_pbgt_hreqave 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neighbour cell : 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Seven Motorola Microcellular Handover Procedures 4–16. . . . . . . . . . . . . . . . . . . . . . . . .

Type 1 Algorithm 4–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PBGT algorithm 4–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Downlink RXLEV only 4–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



vi

Adapted Power Consideration 4–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Uplink Consideration 4–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example One – Equally Sized Cells 4–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Example Two – Large server, Small Neighbour 4–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 1 4–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power budget exercise part 1 4–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power budget exercise part 2 4–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Criteria 1 4–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Criteria 2 4–34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 1 Algorithm 4–36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Uses 4–36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 2 Algorithm 4–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 3 Algorithm 4–40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GSR5 Enhancements 4–40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 4 Algorithm 4–42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 5 Algorithm 4–44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Algorithm Description 4–44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Optimisation of type 5 handovers 4–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 6 Algorithm (Delay PBGT using Dynamic ho_margin) 4–48. . . . . . . . . . . . . . . . . . . . . . . Description of variables 4–48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Algorithm Definition 4–48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Handover Scenario for Adjacent Channels (Both BCCH Carriers) 4–50. . . . . . . . . . . . . . . . . .

Type 7 Algorithm 4–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Algorithm Definition 4–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interference Avoidance Test 4–56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 4–56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Setting of Candidate List 4–58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Handover Margin Per Cause 4–60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handover Margin Per Cause 4–60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Application 4–60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RXQUAL and Microcell Enhancements 4–63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timed Offset upon RXQUAL Handover 4–63. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Micro – Micro Quality Handover 4–65. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ordering 4–65. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Handovers Adaptive 4–67. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overview 4–67. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Handovers 4–69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adaptive Receive Level handovers. 4–69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Receive Quality Handovers 4–71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hopping Parameters 4–71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Power Budget Handovers 4–73. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Outline 4–73. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cumulative Area 4–73. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Example Application Scenarios for Handover Procedures 4–75. . . . . . . . . . . . . . . . . . . . . . . . Imperative handover from microcell to macrocell 4–75. . . . . . . . . . . . . . . . . . . . . . . . . . Hand–down from macrocell to microcell (handover to a type 5 neighbour) 4–75. . . . . Handover to a type 3 neighbour (round the corner handover) 4–75. . . . . . . . . . . . . . . . Handover to a line–of–sight neighbour 4–75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Applying the algorithms 4–75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



vii

Exercise 4–77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Database Parameters 4–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . add_neighbor 4–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Separate BA Lists 4–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 5Capacity Enhancing Database 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Capacity Enhancing Database 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Directed Retry 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Congestion relief 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Congestion Handover Criteria 5–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enabling Directed Retry 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Emergency and EGSM calls 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microcellular purchasable option 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TCH flow control 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Directed Retry and External Handovers 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Congestion relief 5–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Congestion Relief – Standard Parameters 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Database Parameters 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timers 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Congestion Relief – Type 2 Parameters 5–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Associated Congestion Parameters 5–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Concentric Cells 5–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multiband 5–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Based Concentric Cells 5–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handover to Inner Zone 5–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Based Concentric Cells – HO to Inner Zone Power Level 5–22. . . . . . . . . . . . . . . . . . Overview 5–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handover to Inner Carrier 5–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Concentric Cells 5–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handover to Outer Zone 5–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interference Based Concentric Cells 5–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overview 5–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interference Based Concentric Cells 5–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Budget Calculation 5–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mobile Power Factor 5–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interference Based Algorithm – Handover to Inner Zone 5–30. . . . . . . . . . . . . . . . . . . . . . . . .

Direct Inner Zone Threshold and Neighbour Report Timer 5–32. . . . . . . . . . . . . . . . . . . . . . . .

Interference Based Algorithm – Handover to Outer Zone 5–34. . . . . . . . . . . . . . . . . . . . . . . . .

Power Control When Using Interference Algorithm 5–36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Concentric Cells – Channel Allocation Rules 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . outer_zone usage_level 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flow Control 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . intra_cell_handover_allowed 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Emergency call pre–emption 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Immediate Assignments 5–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



viii

Multiband Inter–cell Handover 5–40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multiband Inter–cell Handover 5–41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Multiband Database Parameters 5–44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enhanced SDCCH to TCH (preferred band) Assignment 5–46. . . . . . . . . . . . . . . . . . . . . . . . .

Multiband Neighbour Measurement 5–48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MSC Requirements 5–50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ALM for EGSM Carriers 5–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EGSM Layer Management 5–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Database parameters 5–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neighbour Re–ordering 5–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ALM for EGSM Carriers Examples 5–54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 1 5–54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 2 5–54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Coincident Multiband Handover 5–58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Feature objectives 5–58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cell Definitions 5–58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Configuring Coincident Multiband 5–60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Coincident Multiband External Neighbour Enhancements 5–62. . . . . . . . . . . . . . . . . . . . . . . . . Operation 5–62. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Single BCCH for Dual Band Cells 5–64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Feature Overview 5–64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Single BCCH for Dual Band Cells 5–66. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Feature Overview (Continued) 5–66. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Types 5–68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Primary Band 5–68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Secondary band 5–68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dependancies 5–68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Modification Overview 5–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . inner_zone_alg <value>cell=<cell_desc> 5–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Equipping DRI and RTF groups 5–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Outer zone usage 5–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dual band Inner Zone use Algorithms 5–72. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Propagation Differences 5–72. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power losses 5–72. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dual Band Inner Zone Algorithms 5–74. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dual Band Inner Zone Use Algorithms 5–76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Algorithms 5–76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dual Band Inner Zone Use Algorithms 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BTS Power Control on 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BTS Power Control off 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MS Power Control on 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MS Power Control off 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handovers to n/bours 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enabling the Dual Band Feature 5–80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multiband 5–80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Handover and Power Control 5–82. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



ix

Handover and Power Control 5–83. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Budget Calculation 5–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Budget Mode 5–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Handover Power Level Inner 5–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmit Power Capability 5–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dependancies 5–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EGSM Layer Management Within a Dualband Cell 5–86. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Extended Range Cell 5–88. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Timeslot Allocation 5–90. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Extended Range Cell parameters 5–92. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Extended Range Handovers 5–94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intra–cell Handovers 5–94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inter–cell Handovers 5–94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RF Planning Guidelines 5–96. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maximizing Output Power 5–98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maximizing Receiver Sensitivity 5–100. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 6Adaptive Multi–Rate and Half–Rate 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Multi–Rate and Half Rate 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Half Rate 6–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adaptive Multi–Rate (AMR) 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AMR Full – Rate Channel Mode 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Full Rate Link Adaptation 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AMR Half – Rate Channel Mode 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Half Rate Link Adaptation 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Active Codec Set Values 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AMR Half–Rate Further Considerations 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enabling Half Rate 6–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RTF Change 6–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Channel Allocation for AMR 6–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Speech 6–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Force Half–Rate 6–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reconfiguration of Existing Full–Rate Calls 6–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reservation of Half–Rate Resources 6–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AMR Full – Rate Link Adaptation 6–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AMR Half – Rate Link Adaptation 6–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enabling/Disabling Link Adaptation 6–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AMR FR/HR Commands to Specify ACS and Associated Parameters 6–22. . . . . . . . . . . . . .

AMR FR/HR Commands to Specify ACS and Associated Parameters–Cont’d 6–24. . . . . . . Downlink Adaptation Change Minimum Time Period 6–26. . . . . . . . . . . . . . . . . . . . . . .

MS Monitor Functionality 6–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Downlink Adaptation MS Monitor Parameters 6–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(AMR) Half Rate Handover and Power Control Parameters 6–30. . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



x

AMR or GSM Half–Rate Intracell Handovers 6–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AMR or GSM Half Rate Intra–cell Handover Hop Count 6–34. . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 7Planning of Microcells 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planning of Microcells 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objectives 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Steps in Planning Microcellular Systems 7–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Identification of requirements 7–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quality of Service Targets 7–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traffic capacity enhancement 7–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erlang 7–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erlang per subscriber 7–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Channel Blocking 7–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 7–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traffic Capacity Enhancement Student Exercise 7–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dimensioning of Signalling Channels 7–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planning for Hotspots 7–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Detection of Hotspot cells 7–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Frequency Planning 7–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example 7–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Macro Frequency Reuse 7–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Requirements for Calculating Link Budgets 7–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minimum Coupling Loss Considerations 7–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Designing with Close Proximity Mobiles 7–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modulation Spectrum drop–off with frequency Offset 7–22. . . . . . . . . . . . . . . . . . . . . . .

Designing with Close Proximity Mobiles Calculations 7–24. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Uplink Budget Calculation Comparisons 7–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Link budget with Close Proximity Mobiles 7–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Link Budget without Close proximity Mobiles 7–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusions 7–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Link Budget for Balanced Downlinks 7–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Link Budget with close Proximity Working 7–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Link Budget without Close Proximity Working 7–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The In–Building Solution 7–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction to picocellular 7–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Picocellular Benefits 7–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

In–building Coverage 7–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Propagation from outside to inside 7–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

In–Building RF Repeaters 7–34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RF repeater with cell enhancer 7–35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operation from Tall Buildings 7–36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Antenna Types 7–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Directional antennas 7–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

OMNI antennas 7–40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Version 1 Rev 0



xi

Installation of Microcell Antennas 7–42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diversity 7–42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Horizonmicro2 7–44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M–Cellcity & M–Cellcity+ 7–44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Antenna types for Picocellular 7–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Directional antenna 7–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Omni antenna 7–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation of antennas 7–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Designing with Radiating Cable 7–48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ��

Version 1 Rev 0



xii

Version 1 Rev 0



xiii

List of Figures

Version 1 Rev 0



xiv

List of Tables

Version 1 Rev 0 General information



1

General information

Important notice

If this manual was obtained when attending a Motorola training course, it will not beupdated or amended by Motorola. It is intended for TRAINING PURPOSES ONLY. If itwas supplied under normal operational circumstances, to support a major softwarerelease, then corrections will be supplied automatically by Motorola in the form ofGeneral Manual Revisions (GMRs).

Purpose

Motorola cellular communications manuals are intended to instruct and assist personnelin the operation, installation and maintenance of the Motorola cellular infrastructureequipment and ancillary devices. It is recommended that all personnel engaged in suchactivities be properly trained by Motorola.

WARNING Failure to comply with Motorola’s operation, installation andmaintenance instructions may, in exceptional circumstances,lead to serious injury or death.

These manuals are not intended to replace the system and equipment training offered byMotorola, although they can be used to supplement and enhance the knowledge gainedthrough such training.

ETSI standards

The standards in the table below able are protected by copyright and are the property ofthe European Telecommunications Standards Institue (ETSI).

ETSI specification number

GSM 02.60 GSM 04.10 GSM 08.08

GSM 03.60 GSM 04.11 GSM 08.16

GSM 03.64 GSM 04.12 GSM 08.18

GSM 04.01 GSM 04.13 GSM 08.51

GSM 04.02 GSM 04.60 GSM 08.52

GSM 04.03 GSM 04.64 GSM 08.54

GSM 04.04 GSM 04.65 GSM 08.56

GSM 04.05 GSM 08.01 GSM 08.58

GSM 04.06 GSM 08.02 GSM 09.18

GSM 04.07 GSM 08.04 GSM 09.60

GSM 04.08 GSM 08.06

Figures from the above cited technical specifications standards are used, in this trainingmanual, with the permission of ETSI. Further use, modification, or redistribution is strictlyprohibited. ETSI standards are available from http://pda.etsi.org/pda/ andhttp://etsi.org/eds/

Version 1 Rev 0General information



2

Data encryption

In order to avoid electronic eavesdropping, data passing between certain elements in theGSM and GPRS network is encrypted. In order to comply with the export and importrequirements of particular countries, this encryption occurs at different levels asindividually standardised, or may not be present at all in some parts of the network inwhich it is normally implemented. The manual set, of which this manual is a part, coversencryption as if fully implemented. Because the rules differ in individual countries,limitations on the encryption included in the particular software being delivered, arecovered in the Release Notes that accompany the individual software release.

Cross references

Throughout this manual, cross references are made to the chapter numbers and sectionnames. The section name cross references are printed bold in text.

This manual is divided into uniquely identified and numbered chapters that, in turn, aredivided into sections. Sections are not numbered, but are individually named at the top ofeach page, and are listed in the table of contents.

Text conventions

The following conventions are used in the Motorola cellular infrastructure manuals torepresent keyboard input text, screen output text and special key sequences.

Input

Characters typed in at the keyboard are shown like this.

Output

Messages, prompts, file listings, directories, utilities, andenvironmental variables that appear on the screen are shown likethis.

Special key sequences

Special key sequences are represented as follows:

CTRL–c Press the Control and c keys at the same time.

ALT–f Press the Alt and f keys at the same time.

| Press the pipe symbol key.

CR or RETURN Press the Return key.

Version 1 Rev 0 Reporting safety issues



3

Reporting safety issues

Introduction

Whenever a safety issue arises, carry out the following procedure in all instances.Ensure that all site personnel are familiar with this procedure.

Procedure

Whenever a safety issue arises:

1. Make the equipment concerned safe, for example by removing power.

2. Make no further attempt to adjust or rectify the equipment.

3. Report the problem directly to the Customer Network Resolution Centre, Swindon+44 (0)1793 565444 or China +86 10 68437733 (telephone) and follow up with awritten report by fax, Swindon +44 (0)1793 430987 or China +86 1068423633 (fax).

4. Collect evidence from the equipment under the guidance of the Customer NetworkResolution Centre.

Version 1 Rev 0Warnings and cautions



4

Warnings and cautions

Introduction

The following describes how warnings and cautions are used in this manual and in allmanuals of this Motorola manual set.

Warnings

Definition of Warning

A warning is used to alert the reader to possible hazards that could cause loss of life,physical injury, or ill health. This includes hazards introduced during maintenance, forexample, the use of adhesives and solvents, as well as those inherent in the equipment.

Example and format

WARNING Do not look directly into fibre optic cables or data in/outconnectors. Laser radiation can come from either the data in/outconnectors or unterminated fibre optic cables connected to datain/out connectors.

Failure to comply with warnings

Observe all warnings during all phases of operation, installation and maintenance of theequipment described in the Motorola manuals. Failure to comply with these warnings,or with specific warnings elsewhere in the Motorola manuals, or on the equipmentitself, violates safety standards of design, manufacture and intended use of theequipment. Motorola assumes no liability for the customer’s failure to complywith these requirements.

Cautions

Definition of Caution

A caution means that there is a possibility of damage to systems, software or individualitems of equipment within a system. However, this presents no danger to personnel.

Example and format

CAUTION Do not use test equipment that is beyond its due calibration date;arrange for calibration to be carried out.

Version 1 Rev 0 General warnings



5

General warnings

Introduction

Observe the following specific warnings during all phases of operation, installation andmaintenance of the equipment described in the Motorola manuals:

� Potentially hazardous voltage

� Electric shock

� RF radiation

� Laser radiation

� Heavy equipment

� Parts substitution

� Battery supplies

� Lithium batteries

Failure to comply with these warnings, or with specific warnings elsewhere in theMotorola manuals, violates safety standards of design, manufacture and intended use ofthe equipment. Motorola assumes no liability for the customer’s failure to comply withthese requirements.

Warning labels

Warnings particularly applicable to the equipment are positioned on the equipment.Personnel working with or operating Motorola equipment must comply with any warninglabels fitted to the equipment. Warning labels must not be removed, painted over orobscured in any way.

Version 1 Rev 0General warnings



6

Specific warnings

Specific warnings used throughout the GSM manual set are shown below, and will beincorporated into procedures as applicable.

These must be observed by all personnel at all times when working with the equipment,as must any other warnings given in text, in the illustrations and on the equipment.

Potentially hazardous voltage

WARNING This equipment operates from a hazardous voltage of 230 Vac single phase or 415 V ac three phase supply. To achieveisolation of the equipment from the ac supply, the ac inputisolator must be set to off and locked.

When working with electrical equipment, reference must be made to the Electricity atWork Regulations 1989 (UK), or to the relevant electricity at work legislation for thecountry in which the equipment is used.

NOTE Motorola GSM equipment does not utilise high voltages.

Electric shock

WARNING Do not touch the victim with your bare hands until theelectric circuit is broken.Switch off. If this is not possible, protect yourself with dryinsulating material and pull or push the victim clear of theconductor.ALWAYS send for trained first aid or medical assistanceIMMEDIATELY.

In cases of low voltage electric shock (including public supply voltages), serious injuriesand even death, may result. Direct electrical contact can stun a casualty causingbreathing, and even the heart, to stop. It can also cause skin burns at the points of entryand exit of the current.

In the event of an electric shock it may be necessary to carry out artificial respiration.ALWAYS send for trained first aid or medical assistance IMMEDIATELY.

If the casualty is also suffering from burns, flood the affected area with cold water to cool,until trained first aid or medical assistance arrives.

RF radiation

WARNING High RF potentials and electromagnetic fields are present inthis equipment when in operation. Ensure that alltransmitters are switched off when any antenna connectionshave to be changed. Do not key transmitters connected tounterminated cavities or feeders.

Relevant standards (USA and EC), to which regard should be paid when working with RFequipment are:

� ANSI IEEE C95.1-1991, IEEE Standard for Safety Levels with Respect to HumanExposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz.

� CENELEC 95 ENV 50166-2, Human Exposure to Electromagnetic Fields HighFrequency (10 kHz to 300 GHz).

Version 1 Rev 0 General warnings



7

Laser radiation

WARNING Do not look directly into fibre optic cables or optical datain/out connectors. Laser radiation can come from either thedata in/out connectors or unterminated fibre optic cablesconnected to data in/out connectors.

Lifting equipment

WARNING When dismantling heavy assemblies, or removing orreplacing equipment, a competent responsible person mustensure that adequate lifting facilities are available. Whereprovided, lifting frames must be used for these operations.

When dismantling heavy assemblies, or removing or replacing equipment, the competentresponsible person must ensure that adequate lifting facilities are available. Whereprovided, lifting frames must be used for these operations. When equipments have to bemanhandled, reference must be made to the Manual Handling of Loads Regulations1992 (UK) or to the relevant manual handling of loads legislation for the country in whichthe equipment is used.

Parts substitution

WARNING Do not install substitute parts or perform any unauthorizedmodification of equipment, because of the danger ofintroducing additional hazards. Contact Motorola if in doubtto ensure that safety features are maintained.

Battery supplies

WARNING Do not wear earth straps when working with standby batterysupplies.

Lithium batteries

WARNING Lithium batteries, if subjected to mistreatment, may burstand ignite. Defective lithium batteries must not be removedor replaced. Any boards containing defective lithiumbatteries must be returned to Motorola for repair.

Contact your local Motorola office for how to return defective lithium batteries.

Version 1 Rev 0General cautions



8

General cautions

Introduction

Observe the following cautions during operation, installation and maintenance of theequipment described in the Motorola manuals. Failure to comply with these cautions orwith specific cautions elsewhere in the Motorola manuals may result in damage to theequipment. Motorola assumes no liability for the customer’s failure to comply with theserequirements.

Caution labels

Personnel working with or operating Motorola equipment must comply with any cautionlabels fitted to the equipment. Caution labels must not be removed, painted over orobscured in any way.

Specific cautions

Cautions particularly applicable to the equipment are positioned within the text of thismanual. These must be observed by all personnel at all times when working with theequipment, as must any other cautions given in text, on the illustrations and on theequipment.

Fibre optics

CAUTION Fibre optic cables must not be bent in a radius of less than30 mm.

Static discharge

CAUTION Motorola equipment contains CMOS devices. These metaloxide semiconductor (MOS) devices are susceptible todamage from electrostatic charge. See the section Devicessensitive to static in the preface of this manual for furtherinformation.

Version 1 Rev 0 Devices sensitive to static



9

Devices sensitive to static

Introduction

Certain metal oxide semiconductor (MOS) devices embody in their design a thin layer ofinsulation that is susceptible to damage from electrostatic charge. Such a charge appliedto the leads of the device could cause irreparable damage.

These charges can be built up on nylon overalls, by friction, by pushing the hands intohigh insulation packing material or by use of unearthed soldering irons.

MOS devices are normally despatched from the manufacturers with the leads shortedtogether, for example, by metal foil eyelets, wire strapping, or by inserting the leads intoconductive plastic foam. Provided the leads are shorted it is safe to handle the device.

Special handling techniques

In the event of one of these devices having to be replaced, observe the followingprecautions when handling the replacement:

� Always wear an earth strap which must be connected to the electrostatic point(ESP) on the equipment.

� Leave the short circuit on the leads until the last moment. It may be necessary toreplace the conductive foam by a piece of wire to enable the device to be fitted.

� Do not wear outer clothing made of nylon or similar man made material. A cottonoverall is preferable.

� If possible work on an earthed metal surface or anti-static mat. Wipe insulatedplastic work surfaces with an anti-static cloth before starting the operation.

� All metal tools should be used and when not in use they should be placed on anearthed surface.

� Take care when removing components connected to electrostatic sensitivedevices. These components may be providing protection to the device.

When mounted onto printed circuit boards (PCBs), MOS devices are normally lesssusceptible to electrostatic damage. However PCBs should be handled with care,preferably by their edges and not by their tracks and pins, they should be transferreddirectly from their packing to the equipment (or the other way around) and never leftexposed on the workbench.



1–1

Chapter 1

Introduction to Capacity

Enhancing Techniques and

Multilayer Systems

Version 1 Rev 0



1–2

Version 1 Rev 0 Introduction to Capacity Enhancing Techniques and Multilayer Systems



1–3

Introduction to Capacity Enhancing Techniques and MultilayerSystems

Objectives

On completion of this section the student will have:

� Discussed the reasons why a multi–layer solution would be adopted in a network

� Appreciate the solutions Motorola offers to increase capacity in a network

Version 1 Rev 0Introduction



1–4

IntroductionMotorola has a wide variety of capacity enhancing solutions in RF technology and designapproach

� Macrocellular Technology

� IOS

� Frequency Hopping

� Microcellular Technology

� In–Building Solutions

� Microcellular Handover Algorithms

� Multilayer Technology

� Dualband Technology

� Congestion Relief

� Concentric Cells

� Coincident Multiband

� Single BCCH for Dual Band Cells

� Extended Range Cells

� Adaptive Multi–Rate

All these solutions will be discussed in this course in detail, with the exception ofmicrocellular technology that is reviewed, as it is covered in depth on previousprerequisite courses.

Considerations

These capacity enhancing solutions have there own characteristics and requirements indesign and implementation. To choose the best solution for customer requirements andnetwork specification, the following should be taken into account.

� Available Frequency Spectrum

� Capacity Requirements

� Mobile Handset Availability

� Network Environment

� Ease of Future Expansion

Each network has different drivers for both growth and expansion. National constraintsof frequency, tariffing, subscriber base and competition will determine the cell card.

Every network is different and every network will require different feature deployment.

This course aims to provide the tool box of features to effect growth in a given network.

Version 1 Rev 0 Introduction



1–5

Introduction

GSM900Macro Layer

DCS1800

Micro Layer

Capacity Requirement

Network Environment

– Ease of Future Expansion

– Frequency Hopping

– Concentric Cells

– Dual band Technology (MS Capable)

– In–Building Solutions

– Microcellular Techniques

– Microcellular Handover Algorithms

– Extended range Cells

– IOS

– Congestion Relief

sys12_ch01_01a

Frequency Spectrum Availability

– Coincident mb/Single BCCH

– Multilayer Technology

– Adaptive Multi–Rate

Version 1 Rev 0Frequency Spectrum



1–6

Frequency Spectrum

Re–use Pattern

Each network will have a total number of radio frequencies available. This allocation issplit into a number of channel groups or sets. If the frequency spectrum is contiguousthen guard channels are needed. Each channel group is solely for a particular type ofusage. For example one channel group could be used for the BCCH of macrocells,another for non–BCCH, another for microcells etc. This is a typical single layer withisolated microcells frequency segmenation.

In the case of the multilayer scenario, the segmentation high–rise macrocell, street–levelmacrocell, microcell layer and indoor picocell.

These channel groups are assigned on a per cell basis in a regular pattern that repeatsacross all of the cells. Thus each set may be re–used many times throughout thecoverage area, giving rise to a particular re–use pattern eg, 7 cell re–use pattern.

Frequencies

GSMTx 935 – 960 MHz 124 RF carriersRx 890 – 915 MHz

EGSMTx 925 – 960 MHz 174 RF carriersRx 880 – 915 MHz

DCS1800Tx 1805 – 1880 MHz 374 RF carriersRx 1710 – 1785 MHz

GSM850Tx 869.2 – 893.8 MHz 122 RF carriersRx 824.2 – 848.8 MHz

Version 1 Rev 0 Frequency Spectrum



1–7

Frequency Spectrum

SYS12_Ch01_02

1

2

3

4

5

6

7

1

2

3

4

5

6

7 1

2

3

4

5

6

7

1

2

3

4

5 7

1

3

4

5

6

Frequency Re–use Pattern (omnicell)

7 Cell Re–use

�

�

Version 1 Rev 0Sectorisation



1–8

SectorisationThe capacity of any network is a function of the number of RF channels available and thenumber of times those frequencies can be reused in a given area and the desiredblocking probability. One way to increase the capacity of the network is by frequencyreuse. Frequency reuse can be achieved by sectorisation of existing cell sites.

To increase the coverage and capacity of a network built up of omni–directional cells, theconventional approach is to sectorise the existing cells (i.e. restrict the coverage area ofeach cell to a sector of 120° or 60° of arc thereby allowing increased control of coverageand interference).

In this way, it is possible to reuse frequencies over smaller distances, allowing asignificant increase in network capacity, whilst maintaining the C/I ratio at an acceptablelevel.

4 x 3 Frequency Reuse Pattern

The diagram opposite shows a four site reuse pattern with 120° sectorised cells. This isideal for a new system with moderate subscriber capacity. For the future, if the networkbecomes increasingly dense additional sectorisation and site splitting could be used as amethodology.

If the operator has only 24 carriers allocated for their use, they will be restrictedtheoretically to 2 carriers per cell. This means only 16 channels, which is not a lot if youconsider each cell could contain several office blocks.

A solution to this problem could be the introduction of microcells, which can mean agreater frequency reuse pattern.

Version 1 Rev 0 Sectorisation



1–9

Four Site Pattern

SYS12_Ch01_03

a1

a2

a3

c1

c2

c3

b1

b2

b3

d1

d2

d3

a1

a2

a3

a1

a2

a3

c1

c2

c3

c1

c2

c3

b1

b2

b3

b1

b2

b3

d1

d2

d3

d1

d2

d3

a1

a2

a3

a1

a2

a3

Reuse

120 Sectorso

Version 1 Rev 0Sectorisation



1–10

Sectorisation

2 x 6 Frequency Reuse Pattern

A further solution to network operators capacity problems may be the introduction of sixsector operation.

This technique permits six cells to be controlled from a single base site controller.

Six sector operation can be used to deliver capacity benefits to EGSM900 operators andcoverage benefits to DCS1800 operators.

It employs narrow band antennas which utilize higher transmitted power and a narrowerbeam width coverage than standard antennas. The use of narrow beam antennasresults in a reduction in co–channel interference, which in turn allows tighter frequencyreuse and greater network capacity.

Secondly, it allows a DCS1800 operator to achieve a greater range, due to the hightransmit power and therefore achieve coverage with fewer cell sites. Moreover,penetration into buildings is improved for both EGSM900 and DCS1800.

Version 1 Rev 0 Sectorisation



1–11

Two–Site Pattern

sys12_ch01_04

a1

a2

a3a4

a5

a6

a1

a2

a3a4

a5

a6

b1

b2

b3b4

b6

b1

b2

b3b4

b5

b6

b5

60 Sectors

Version 1 Rev 0Cell splitting



1–12

Cell splittingLater, as the subscriber base grows within a confined area, (usually a town or city), it isnecessary to provide even more capacity in some areas by sub–dividing the cells of thenetwork to position more cells within the same area. This, in turn, reduces the coveragearea of some of the existing cells by introducing antenna tilt techniques.

Finally, after the number of cells has increased, and the area of coverage of each celldecreases to the saturation point, another approach to the provision of increasedcapacity is necessary.

Saturation point

At saturation point investment in expensive rooftop sites has already becomeconsiderable, and any ability to increase capacity further or to cover holes that exist inthe network in areas of already heavy subscriber demand by conventional macrocellularmeans is now exhausted. Subscriber access to the network in these areas is likely tobecome a great deal more problematic, as new subscribers only increase the networkdifficulties. Time of access to the network in these saturation areas will increase steadilyand to aggravate matters further the quality of service as perceived by the subscriber willfall at least as fast.

Worse still, there may be small areas at street level where it is difficult or maybeimpossible to provide adequate coverage because interference restricts further cellreduction. Call continuity for subscribers moving through such areas is likely to be poorand complaints from disappointed subscribers are likely to increase.

Cell size

The number of cells in any geographic area is determined by the number of mobilesubscribers operating in that area. The maximum cell size is mainly determined by thedistance radio waves can travel and the propagation delay this produces.

Large cells

Larger cells are mainly used in remote areas where there are few subscribers, using hightransmission power.

Small cells

Smaller cells cover areas of dense subscriber traffic using low transmission power.These are usually used in urban areas. Some networks may have cells as small as twoor three hundred meters radius in areas of high traffic.

Trade off – large v small

Network operators wish to have their cells as large as possible to keep the cost ofequipment down. They must also ensure that all those wishing to use the cell can gainaccess to it.

The smaller the cell radius, the more handovers required and the chances of co andadjacent channel interference increases. It is harder to find physical locations for cellsand antennas as you increase the number of traditional BSSs. All this has to be taken into consideration when planning a network.

The use of microcells may alleviate some of these problems.

Version 1 Rev 0 Cell splitting



1–13

Network Expansion

sys12_ch_01_05

Version 1 Rev 0Frequency Hopping



1–14

Frequency HoppingFrequency hopping was introduced as a technique to counter jamming and increasesecurity of military communications. It basically operates by changing the frequency usedat regular intervals. It has been adopted in GSM specifications due to being able tocounter two specific problems:

� Multipath Fading: Fading is more apparent at some frequencies and not so muchat others, particularly for slow moving or stationary mobiles. By using differentfrequencies the probability of being continously affected by fading is reduced, sothe transmission link quality is improved. This characteristic is normally referred asFrequency Diversity.

� Interference: If a neighbouring cell is transmitting at the same or adjacentfrequencies then it will cause interference n the source cell. This situation can beavoided by using frequency hopping, because calls will move between differentfrequencies not equally effected by interfering signals.

The frequency is changed on a per timeslot basis, so all bits in a burst are transmitted inthe same frequency.

Version 1 Rev 0 Frequency Hopping



1–15

Frequency Hopping

SYS12_Ch01_07

Multipath Fading

Interference

–Same Channel

–Adjacent Channel

3 7

4

7

3

5

6

3

4 5

7

3 7

4

7

3

5

6

3

4 5

7

(10)

1

(11)

2

(11)

2

(11)

2

1

1

�

�

Version 1 Rev 0Microcellular Techniques



1–16

Microcellular Techniques

Microcellular Systems

As capacity increases, cell size reduces at a rapid rate. The number of cells requiredincreases until saturation point is reached when the available frequency resource andphysical location of equipment limits what can be achieved with traditional cell planningtechniques. Smaller cells also begin to stretch frequency re–use rules and the ability oflocating carriers in close proximity to each other. djacent channel and co–channel criteriaare stretched in a small cell environment, the ability to meet GSM specified levels areseverely tested and restrict what can be achieved without significant degradation ofnetwork performance. These operational limitations restrict the minimum radius of amacrocell to about 500m, which is not enough to meet the capacity and coveragerequirements of dense urban networks.

Microcells have been developed to solve the problems described above. A microcell is acell which is mounted below rooftop level. Radio wave propagation is determined bydiffraction and scattering around buildings, the main rays propagating within streetcanyons. They have a radius of 300m or smaller and exhibit transmission behaviour,which differs from conventional large or small cells. Propagation is primarily “line ofsight” and radio path loss increases sharply as the receiver moves out of sight of thetransmitter. Microcells offer improved propagation properties, experience less severefading and require lower transmitter powers than conventional macrocells.

Motorola PBGT Algorithms

At present there are seven PBGT algorithms that offer an intelligent product able torecognise the needs of the system and direct traffic according to resources andconditions of the network.

To achieve this intelligent functionality, the PBGT algorithm may be configured on aper–neighbour basis, allowing each neighbour to be processed following different criteria.What is configured is not the PBGT formula itself, but its surrounding conditions to triggera handover.

Type 1 : Standard Configuration

Type 2 : Macro Neighbour of a Micro Cell via Imperative Handover

Type 3 : Around the Corner

Type 4 : Line of Sight Configuration

Type 5 : Qualified Neighbour Configuration (Time)

Type 6 : Dynamic Handover Margin Configuration (Time)

Type 7 : Adjacent Channel Neighbours

Version 1 Rev 0 Microcellular Techniques



1–17

Microcellular Handover Algorithms

SYS12_Ch1_08

– LOS primarily

– Less severe fading

– Less transmit power

PBGT Algorithms

Type 1 to type 7

Adaptive handovers

RXLEV

RXQUAL

PBGT

Small Radius Typically100m or less

Version 1 Rev 0Microcellular Techniques, cont.,



1–18

Microcellular Techniques, cont.,

Adaptive Handovers

Normal handovers are triggered by a voting method such that if p from n of the mostrecent rolling averages meet a certain number, then the need for a handover isrecognised. However, this standard method may be too slow to catch a rapidlydeteriorating call. The alternative method of adaptive handovers now exists for Quality,Receive Level and Power Budget handovers. The adaptive handover method causeshandovers to be recognized based on a cumulative area rather than a vote. Theadaptive handover method enables handovers to occur more rapidly when conditions aredeteriorating quickly, but less rapidly when conditions are only marginally poor.

Version 1 Rev 0 Microcellular Techniques, cont.,



1–19

Version 1 Rev 0Multiband Environment



1–20

Multiband Environment

Network operators now have the ability to utilize the GSM900,EGSM, DCS1800,PCS1900 and GSM850 frequency spectrum.

Not only can this environment be supported by multi–band telephones, but also by theability of the Motorola network to support multiband intra–cell and inter–cell handovers.

Multiband inter–cell and intra–cell handovers will provide the BSS with the ability tosupport inter–cell and intra–cell handovers where cells are operating in differentfrequency bands. In addition, the network operator will have the ability to deploy cells ofdiffering frequency bands within the same BTS site(s).

Version 1 Rev 0 Multiband Environment



1–21

Multiband Environment

sys12_ch01_12

GSM 850

GSM 900

DCS 1800

PCS 1900

EGSM

GSM 900 GSM 900

GSM 900

GSM 900 GSM 900

GSM 900

GSM 900 GSM 900

GSM 900

DCS 1800

DCS 1800DCS 1800

DCS 1800

DCS 1800DCS 1800

DCS 1800

DCS 1800DCS 1800

Version 1 Rev 0Half Rate



1–22

Half RateThe GSM Half Rate feature offers enhanced capacity over the air interface,corresponding to the proportion of mobiles within a coverage area that supports HalfRate. An air timeslot is split into two sub–channels, each containing a half rate channel.Speech quality is considered inferior to other speech codecs but has a high penetrationlevel (of GSM HR capable mobiles) due to its early introduction into the standards. Dueto these large penetration levels it is considered a viable option for high density areas.

A GSM HR call can fit within an 8kbps timeslot (an Ater channel) on the terrestrialresource from the BSC to the RXCDR, rather than the 16kbps timeslot required for FRcalls. If a percentage of the active calls can be assumed to be HR, then efficiencies canbe gained by reducing the number of terrestrial resources between the BSC and RXCDR.This is possible only if the BSC can dynamically allocate a timeslot to a CIC on an8kbps/16kbps basis. This dynamic allocation is performed across a trunked interfacebetween the BSC and a remote transcoder (RXCDR). This interface is called the Aterinterface. The dynamic allocation is an enhancement to the existing Auto Connect modefeature, referred to as ”Enhanced Auto Connect mode”. Enhanced Auto Connect is partof the AMR feature and is mentioned here only to point out that GSM HR will enjoy thesame benefit.

The backhaul requirements between the BTS and BSC may also be reduced to 8kbps aslong as subrate (8K) switching is present at the BSC. Both GDP and GDP2 boards willbe enhanced to support GSM HR. GDP will be introduced first, followed by GDP2 in afuture release.

Version 1 Rev 0 Half Rate



1–23

Half Rate

SYS12_ch1_13

432107654321076543210765 432107654321076543210765 5

432107654321076543210765 432107654321076543210765 5

Full Rate Speech

Half rate channel

Half rate channel

Version 1 Rev 0Adaptive Multi–Rate (AMR)



1–24

Adaptive Multi–Rate (AMR)Adaptive Multi–Rate (AMR) is introduced in GSR7 and provides two modes of workingAMR full–rate channel mode (AMR FR) and AMR half–rate channel mode (AMR HR).

AMR Full – Rate Channel Mode

This mode of working provides higher speech quality in areas of poor RF conditions.

Full Rate Link Adaptation

AMR FR link adaption works in conjuction with the rest of the AMR feature set, namelyAMR, Call downgrade on CIC capability mismatch and Enhanced GDP provisioning. Itprovides improved speech quality in poor RF environments by adapting the speech ratesand level of error correction on a call. Speech quality is improved by reducing the speechrate and increasing the level of error correction in poor RF environment.

AMR Half – Rate Channel Mode

This mode of working allows two AMR calls to be placed on a single air interfacetimeslot. This gives an increase in cell capacity with no additional hardware. Howeverextra backhaul is required between BSC and BTS due to there being no 8kbps switchingin release GSR7. There is also a lower QoS provided by AMR half–rate calls.

Half Rate Link Adaptation

AMR HR link adaption operates in a similar way to AMR FR link adaption. Thedifferences are the bit rates of the HR codec modes supported, different initial HR codecmode and differnt associated uplink and downlink codec mode adaption thresholds andhystersis values.

Version 1 Rev 0 Adaptive Multi–Rate (AMR)



1–25

Adaptive Multi–Rate (AMR)

SYS12_amr_01

MSC RXCDR BSC BTS

0

For half rate rtf – two E1 timeslots required

Dependant on:–Enhanced GDP Provisioning–Call downgrade on CIC

capability mismatch

Up to four codecmodes can beincluded in FR and

HR Active CodecSet

Which Codec Modeused depends onRF conditions

Up to 16 AMR half rate calls

Up to 8 AMR full rate calls

Or a combination of the two.

Version 1 Rev 0Concentric Cells



1–26

Concentric Cells

Purpose of Concentric Cells

Concentric cells are a feature that has been developed to allow a regular frequencyreuse pattern, for example 4 x 3. Or to have a super frequency reuse pattern, forexample 2 x 3 or 1 x 3 superimposed upon it. These two groups have a single BCCHfrequency operating in the same coverage area. The BCCH provides coverage to theentire area of the cell, this area is known as the outer zone (zone 0), this zone could alsocontain non–BCCH frequencies. The rest of the non–BCCH frequencies are contained ina smaller area with the overall coverage area, this area is known as the inner zone (zone1). Zone 0 is reserved for carriers that transmit at maximum level. This cell structureprovides increased capacity through more efficient re–use of the inner zone frequencies.

The operator can select between two different use algorithms when defining zone 1 in acell:

� Power based Algorithm

� Interference Based Algorithm

MS assignment to the inner or outer zone is based on the received signal level of theserving cell (power–based algorithm) or a comparison of signal levels from the servingand neighbour cells (interference based algorithms). Transitions between zones iscontrolled using intra–cell procedures.

Concentric cells are described in detail in chapter 5.

Version 1 Rev 0 Concentric Cells



1–27

Concentric Cells

SYS12_Ch01_14

Zone 0 – Outer Zone

Zone 1 – Inner Zone

BCCHBroadcast at max txlevel defined for thatcell

Non – BCCHTransmitting at

lower power thanBCCH or

Having a tighterreuse pattern that

reduces the usefulcoverage area of

the carrier

Power Based Algorithm Interference Based Algorithm

Other non_BCCH carriers




1–28

Implementation of Multiband

Introduction of carriers on different frequency bands

New carriers with a different frequency band can be introduced into an existing network.This effectively means that there are two sets of cells, but the equipment is located in thesame geographical position. The two options below allow for a more refined solution tothe implementation of multiband.

Coincident Multiband

This feature enables operators to install new radios in a different frequency band. Thisinstallation will turn an operator’s network into a multiband network. One obstacle to thistype of upgrade is the investment in time and money already made by the operator inoptimising the existing network. With the addition of a secondary network, with differentpropagation characteristics, this optimisation effort would have to be repeated. This candeter some operators, who want the extra capacity, from installing a multiband network.

To avoid this problem of optimising two networks, it is logical that the new secondarynetwork should complement the existing infrastructure. To achieve this, the softwaremust be configurable enough to allow the new network to use the same cell boundariesestablished by the original network. This can be done by using mobile–reportedmeasurement reports of the primary network while established on the secondarynetwork. This allows the mobile to be handled as if it were on the primary network, usingthe primary’s boundaries and minimizing propagation characteristics differences, whilstnot taking any primary network resources.

This feature requires two BCCH carriers, one for each frequency band.

Single BCCH for Dual Band Cells

This is a feature developed in GSR 5 software release. GSM specifications allow the useof a common BCCH for different bands of operation when resources across all bands areco–located and synchronised. With this feature it is possible for carriers within a cell to beconfigured in different frequency bands.




1–29

Concentric Cells Implementation with Dualband

sys12_ch01_15

Coincident Multiband


Two sets of cells with the equipment in the same geographical position

Version 1 Rev 0Directed Retry and Congestion Relief



1–30

Directed Retry and Congestion Relief

Directed retry and congestion relief are software based techniques which can be used toincrease capacity in very dense cellular systems where there is significant coverageoverlap from neighbouring cells. Calls in the overlap region can be maintained on morethan one cell with sufficiently high quality.

Directed retry

Directed retry allows handover of a mobile station from an SDCCH of one cell directly toa TCH of another cell. A directed retry handover procedure may be initiated when amobile station, which is assigned to a SDCCH, requires a traffic channel at a time whenall TCHs in the same cell are busy. The system queues the traffic channel request andexecutes a selection process to determine whether any neighbouring cell is a validcandidate for receiving a directed retry handover.

Congestion relief

This procedure is activated when a mobile station assigned to an SDCCH requires atraffic channel and none are available.

Two options are offered for deciding how many handover procedures are actuallyinitiated. One option is that the number of handover procedures initiated is at most thenumber of outstanding requests for a TCH. The second option allows for initiation of ahandover procedure for each mobile station that meets the modified criteria to supportthe feature.

Version 1 Rev 0 Directed Retry and Congestion Relief



1–31

Directed Retry and Congestion Relief

SYS12_Ch01_16

Directed Retry

MS establishedon SDCCH, butno TCHsavailable

MS handed over toqualified neighbour

Congestion Relief – Type 1

As many MSshanded out asin queue

Congestion Relief – Type 2

As many MSthat qualify forhandover,regardless ofqueue

�

�

�

Version 1 Rev 0Extended Range Cells



1–32

Extended Range CellsThis feature allows the range of a cell to extend from 35Km for normal range timeslots toan extended range of 121Km. This is used when the extra range is required, for exampleislands situated up to 121km from the coastline, with a low subscriber base.

Version 1 Rev 0 Extended Range Cells



1–33

Extended Range Cells

sys12_ch01_17

35 km Normal range Cells

121 km Extended Range Cells

Version 1 Rev 0Extended Range Cells



1–34



2–1

Chapter 2

Frequency Hopping

Version 1 Rev 0



2–2

Version 1 Rev 0 Frequency Hopping



2–1

Frequency Hopping

Objectives

On completion of this section the student will have:

� Reviewed the implementation of baseband and synthesiser frequency hopping

� Discussed the planning considerations for frequency hopping

� Discussed the capacity gain that frequency hopping gives

� Discussed the optimisation issues relating to frequency hopping

Version 1 Rev 0Introduction



2–2

IntroductionFrequency hopping has been around for many years and was first introduced in militarycommunication systems to help secrecy and combat jamming techniques. The mostbasic explanation is the frequency changes at regular intervals.

It has been adopted into GSM to increase capacity and quality in a network as subscribergrowth continues. In addition to this frequency hopping can be rolled out very easily as italready utilises existing network infrastructure.

Multipath Fading

It is well known that when considering a cellular urban environment in most casesmultipath propagation will be present and, as a consequence of that, important short termvariations in the received level are frequent. This is called Rayleigh fading and results inquality degradation because some of the information will be corrupted.

For a fast moving mobile, the fading situation can be avoided from one burst to anotherbecause it also depends on the position of the mobile so the problem is not so serious,but for a stationary one the reception may be permanently affected resulting in a verybad quality, even a drop call.

Once the information is received by the mobile or the base station, the only ‘weapon’ tocope with the disturbance produced by the fading (errors in the information bits) are thedecoding and deinterleaving processes, with an effectiveness limited by the number oferrors they have to deal with.

Frequency hopping is able to take advantage of the frequency selective nature of thefading to decrease the number of errors, at the same time that they are temporallyspread. If a mobile is stationary (or quasi stationary) at a point where a deep fade existson the frequency in question and the system uses frequency hopping, the call will spendtime on frequencies that are not fading at that point. As a result, the decoding anddeinterleaving processes can more effectively remove the bit errors caused by burstsreceived whilst on the faded frequencies (errors will be randomly distributed instead ofhaving long bursts of errors). This increase in effectiveness leads to a transmissionquality improvement of the same proportion.

Interference

The second effect of frequency hopping is referred as averaging the interferenceexperienced by the calls. Considering a non hopping system, the set of calls on theinterferer cells which can interfere with the wanted call is fixed for the duration of thosecalls and some calls will be found with very good quality (no interference problems) andsome others with very bad quality (permanent interference problems). With hopping, thatset of interfering calls will be continually changing and the effect is that calls tend toexperience an average quality rather than extreme situations of either good or bad quality(all the calls will suffer from a controlled interference but only for short and distant periodsof time, not for all the duration of the call).

Version 1 Rev 0 Introduction



2–3

Introduction

Non hopping

Hopping freq 1

Hopping freq 2

Error burstError burst

Radio selectsburstRadio selectsburst

Radio does notselect burstRadio does notselect burst

Version 1 Rev 0Frequency Hopping Basics



2–4

Frequency Hopping BasicsSynthesiser Frequency Hopping (SFH)

The transceiver unit re–tunes to a different operating frequency set (Tx & Rx) on eachTDMA burst (approx 577µs). The re–tuning will follow the sequence explained in thefollowing section. In theory, there is no restriction on the number of frequencies thetransceiver unit can hop on. However, GSM specifications limit the total number to 64frequencies for a SFH transceiver unit.

Base Band Hopping (BBH)

In this method, the transceiver unit will always transmit at an assigned frequency.Frequency hopping is done by switching the information frame of one call from one radio,to another within a cell, per TDMA burst (approx 577µs). The switching of radios willfollow the sequence defined in FHI, as explained below. The resultant transmitted signalon the air–interface is identical to SFH. Please note that the uplink path will not use BBHand the radio on which the call is established will always receive the uplink signal fromthe MS. All the processing (e.g. coding, interleaving etc) will be carried out by this radioand the processed information will be routed to different radios for transmission.

GSM recommendation defines the following parameters for a frequency hopping systemand they are sent from the BTS to MS in the assignment messages during call set up.

Mobile Allocation (MA): This is the set of frequencies the mobile/BTS are allowed tohop over. Two time–slots on a same radio of a cell may be configured to operate ondifferent MA. MA is the subset of the total allocated spectrum for the GSM operator andthe maximum number of frequencies in a MA list is limited by GSM recommendation to64.

Mobile Allocation Index Offset (MAIO): This is an integer offset that determines whichfrequency within the MA will be the operating frequency. If there are N frequencies in theMA list, then MAIO = {0, 1, 2, … N–1}. The first channel from which to hop, as set in theMA, is set by equip <site> RTF , it can be changed by chg_rtf_freq . Used to set theMAIO, which defines the channel from which the MS is to hop.

Hopping Sequence Number (HSN): This is an integer parameter that determines howthe frequencies within the MA list are arranged. There are 64 HSN defined by GSM. HSN= 0 sets a cyclical hopping sequence where the frequencies within the MA list arerepeated in a cyclical manner.

HSN = 1 to 63 will provide pseudo random hopping sequence. The pseudo randompattern will repeat itself after every hyperframe, which is equal to 2,715,648(26x51x2048) TDMA frames or about 3 hours 28 minutes and 54 seconds.

Motorola defines a Frequency Hopping Indicator (FHI) that is made up of the abovethree GSM defined parameters. Up to 4 different FHI can be defined for a cell in aMotorola BSS and every time–slot on a radio can be assigned one of the defined FHI,independently.

Version 1 Rev 0 Frequency Hopping Basics



2–5

Frequency Hopping Basics

sys12_ch02_02

chg_element hopping_support <*><location>cell=<cell_desc>

* 0 = No Hopping1 = Synthesiser hopping

2 = Baseband hopping

* = 0 disabled

* 0 (cyclic)

1 to 63 (Pseudo random hopping)

chg_hopping<cell_desc><FHI><f1>[<f2>].......[<f64>]

equip<site no>rtf – used to set ARFCN which defines the MAIO, the frequency

from which to begin to hop

chg_element hopping_systems_enabled, <index><*><location>cell=<cell_desc >

index = 0 – 3 (FHI) or 255

chg_element hopping_systems_hsn, <FHI><*><location>cell=<cell_desc>1 enabled

Version 1 Rev 0Base Band Frequency Hopping (BBH)



2–6

Base Band Frequency Hopping (BBH)Its main characteristic is that the transmitting units (radios) are always transmitting afixed frequency and frequency hopping is performed by moving the information for everycall among the available radios on a per burst basis. A call will start in a particulartimeslot of one radio and will move to the same timeslot of the other radios spending thetime associated to a burst (about 577 microsec.) in each radio (and hence in eachdifferent frequency). Changing the frequency implies changing the radio (the call hopsbetween Radios). It must be noticed that although data are transmitted by differentradios, all the processing (coding, interleaving, etc.) is done by the digital part associatedto the radio the call was initially assigned to, and only after that, the information is routedto the corresponding transmitting unit.

Looking at the uplink, MS to BS direction, the call is always processed by the radio thecall was initially assigned to.

The table in the diagram will explain the performance: Assuming a cell with 4 radios and4 frequencies (f1 to f4), doing Base Band Hopping in a cyclic way and a call assigned toradio 3 timeslot 5, the call process will be described.

The first consequence is that as many radios as frequencies in the hopping sequenceneed to be physically equipped in the cell, which means that the restriction in the numberof frequencies to hop over will come from the traffic requirements in the cell (number ofradios equipped in the cell). At the same time, because the radios do not need to retuneeach burst, this type of FH can be used in cells where the combination of transmissionsignals to the antenna is done through Remote Tune Combiners (high capacity cellsusually equip that kind of combiners).

As required by the GSM system, the BCCH frequency must be always on the airtransmitting the maximum power (Power control do not apply for BCCH carriers), andparticularly its timeslot 0 cannot hop (if additional Common Control Channels –CCCH–are allocated in other timeslots –1 to 7–, they will not be allowed to hop as well). Fromthe working philosophy described for BBH there is no problem at all for timeslots 1 to 7 ofthe BCCH carrier to hop (provided that they are not used to allocate CCCHs) since thepermanent presence of this frequency on the air is guaranteed, but the bursts using thisfrequency will be transmitted at maximum power. This is another important point in BBH:The BCCH frequency can be included in the hopping sequence and also the BCCHcarrier can carry hopping calls in timeslots 1 through 7. If Downlink Power Control isenabled in the Base Station it will only take effect for the bursts transmitted in thenon–BCCH frequency.

Version 1 Rev 0 Base Band Frequency Hopping (BBH)



2–7

Base Band Frequency Hopping

sys12_ch0203

BCCH f1

Tx Rx

Call assigned to radio 3 (f3) timeslot 4

Tx Rx Tx Rx Tx Rx

f1

f1

f1

f1

f1

f1

Other control t/s non – hopping

Timeslot 0 non – hopping

f2 f3 f4 f4

Non – BCCH f2 Non – BCCH f3 Non – BCCH f4

Burst number 1 2 3 4 ............................cyclic

Version 1 Rev 0Synthesiser Frequency Hopping (SFH)



2–8

Synthesiser Frequency Hopping (SFH)

In this type of hopping the radio changes the transmitting frequency each burst and thecall always stays in the same radio where it started. Motorola equipment has had SFHavailable since 1992 and a high reliability in implementing this kind of hopping has beenachieved. The radio is able to retune to a different frequency for transmission every 577microsecs., and because such fast frequency changes, Remote Tune Combiners (RTC)must not be equipped if synthesiser FH is to be used. So, Synthesiser FrequencyHopping requires the use of wideband combiner devices such as hybrid combiners.

The main advantage of SFH is that there is no restriction on the number of carriersequipped in the cell. The number of radios will be determined by the traffic needed to behandled, but they can hop up to over 64 different frequencies (limitation coming fromGSM specifications) if they are available according to the planning.

Since with SFH the number of frequencies can be greater than the number of carriers, ifthe BCCH frequency is included in the hopping sequence, its presence on the air wouldnot be guaranteed unless the BCCH carrier transmits it when no other carrier does. Thishas two implications:

� The BCCH frequency can be included in the hopping sequence, (SFH throughBCCH) but timeslots 1 to 7 from BCCH carrier cannot be used to carry trafficbecause they must be reserved to put the BCCH frequency on the air whennecessary (dummy Bursts –DB–). At the same time, for the bursts transmitted inthe BCCH frequency the radios will do it at the same power used by the BCCHcarrier (BCCH power).

� The BCCH carrier will never hop. It will either carry traffic in timeslots 1 to 7 on theBCCH frequency (if not included in the hopping sequence) or transmit dummyframes.

Because of this, BCCH frequency is not included in the hopping sequence, so BCCHtimeslots do not hop and non–BCCH timeslots do. The example below and oppositeshows a more detailed explanation of this.

Assuming a cell with 2 radios and 5 frequencies (fb for the BCCH and f1, f2, f3 and f4 forhopping –fb being the lowest one–), doing Synthesiser Hopping in a cyclic way on radio 2and a call assigned to radio 2 timeslot 5 the call process is described in the diagramopposite.

Transmission and reception are always routed through the same timeslot in the samecarrier (it does not happen for transmission in Base Band Hopping). In this case, fortimeslot 5, depending on the inclusion of BCCH frequency in the hopping sequence ornot, the evolution of the call will be different

Motorola equipment allows the system operator to define the hopping system on a pertimeslot basis. So, allowing different hopping configurations for different timeslots. This isvery useful for the purpose of interference averaging and to randomise the distribution ofthe errors.

Version 1 Rev 0 Synthesiser Frequency Hopping (SFH)



2–9

Synthesiser Frequency Hopping – through BCCH

FHI 0 =fb, f1, f2, f3, f4

BCCH frequency: fb

Hopping frequencies: f1, f2, f3, f4

Call assigned to radio 2 timeslot 5

Burst number 1

Tx Rx Tx RxTx RxTx Rx Tx RxTx Rx

2 3 4 5 6 ..........cyclic

sys12_ch0204

BCCH


Timeslot 0 non – hopping

Non – BCCH

fb

fb

fb

fb

fb

fb

Version 1 Rev 0Synthesiser Frequency Hopping (SFH)



2–10

Version 1 Rev 0 Synthesiser Frequency Hopping (SFH)



2–11

Synthesiser Frequency Hopping – not through BCCH

sys12_ch02_05

BCCH


Timeslot 0non – hopping

Non – BCCH

fb

fb

fb

fb

fb

fb f1

BCCH Frequency fb

Hopping frequencies f1, f2, f3, f4

Tx Rx Tx Rx

Call assigned to radio 2 timeslot 5

Burst number 1 2 3 4 5 ...............cyclic

FHI = f1, f2, f3, f4

Version 1 Rev 0Frequency Hopping Enhancements



2–12

Frequency Hopping Enhancements

chg_hop_params

If any of the hopping parameters are changed, by using the database parameterspreviously discussed in this chapter, the site is reset. By using the chg_hop_paramscommand it allows under most circumstances frequency hopping parameters to bechanged without resetting the site. The exception being if a hopping system is enabled,disabled or changed which is synthesiser hopping through the BCCH frequency. Oncethe system accepts the chg_hop_params command, the system displays a warningmessage that the site will reset. When this parameter was introduced it also allowed bothsynthesiser and baseband hopping in different cells at the same site as well as beingable to mix non–hopping cells and hopping cells.

Multiple hopping parameters can be changed at the site at one time by using thechg_hop_params command but once the system excepts the chg_hop_paramscommand for a particular cell, the system rejects other chg_hop_params command untilthe system reconfiguration due to the first command is complete.

The operator may change hopping support from no hopping to baseband hopping, orfrom no hopping to synthesizer hopping, or vice versa, provided that all FHIs for the cellare disabled.

Version 1 Rev 0 Frequency Hopping Enhancements



2–13

Frequency Hopping Enhancements

sys12_ch02_06

chg_hop_params<site>[<cell_desc>]

hoping systems (FHIs) to be modified: in cell <cell_desc>(return=no change for this cell):<fhi 1>........<fhi n>

hopping support: 0 = no hopping1 = synthesizer2 = baseband

FHI <fhi 1> status: 0=disable 1 = enable

Mobile allocation (ARFCNs) for FHI<fhi 1>:<arfcn 1>......<arfcn n>

HSN for FHI<fhi 1>: 0=cyclic 1– 63= pseudo–random

”warning: The site will reset if the operator enabled, disabled or changed

BCCH RTF. Are you sure (y = yes, n = no)?”hopping system which is synthesiser hopping through the

Version 1 Rev 0Frequency Redefinition



2–14

Frequency RedefinitionThis conforms to the Frequency Redefinition procedure defined in TS GSM 04.08 version4.17.0. Before this feature was implemented an MS assigned to a channel that isaffected by the hopping reconfiguration would either be handed over to a channel notaffected by hopping reconfiguration or dropped if there are no channels available. Withthis feature the MS is able to dynamically adjust to the new hopping parameters, thusavoiding any handovers or dropped calls.

Frequency Redefinition will only occur when certain changes occur. These differ forbaseband and synthesiser hopping in as much as enabling or disabling a FHI, changingthe HSN of an enabled FHI are common for both. But because the actual frequenciesthat are being hopped through are determined by the number of radios actually equippedfor baseband hopping and for synthesiser hopping by the mobile allocation which cancontain up to 64 different frequencies, Frequency Redefinition occurs differently for thetwo types. For baseband if a carrier with hopping timeslots transitions from INS to OOSor vice versa then Frequency Redefinition occurs, changing the mobile allocation whilstbaseband hopping is not allowed. For synthesiser hopping changing the mobile allocation(which is allowed) of an enabled FHI causes Frequency Redefinition to occur. However, iftimeslots are taken OOS they continue to transmit so no hopping reconfiguration needsto be done on corresponding timeslots using the same frequency hopping system. Thesame criteria are imposed when timeslots come back into service.

The feature was designed with the following requirements in mind.

1. Any calls on a channel which are undergoing a hopping reconfiguration will not behanded over or have the call released.

2. Channels that are undergoing a hopping reconfiguration will be made available forintra–cell handovers from another carrier going OOS if there are idle channelsavailable.

3. Any calls trying to establish on a SDCCH or TCH shall not be granted a SDCCH orTCH that is undergoing hopping reconfiguration. Hopping reconfiguration takesbetween 10 – 20s for old gen equipment and milliseconds for newgen.

4. All calls on a channel that is undergoing hopping reconfiguration will be notified ofthe new hopping changes via the Frequency Redefinition message. Basically thismessage includes the new hopping parameters together with a start time in termsof an absolute frame number.

5. Upon an error condition (MS gets MA containing ARFCNs that are not all in oneband) and the start time has NOT elapsed then the MS stays on the currentchannel and sends the RR STATUS message back to the BSS. The RR STATUSmessage will contain the cause value, (Frequency Not Implemented). If the starttime has elapsed then the MS aborts the radio connection and, if permitted,attempts Call Re–establishment.

Version 1 Rev 0 Frequency Redefinition



2–15

Frequency Redefinition

BTSBTSBTS

Hoppingreconfiguration

occurs

Frequency Redefinition messagesent to MS containing:

• Start time (TDMA frame no)

• Mobile allocation

• HSN

• MAIO

MS indedicatedmode

• If there is an error and start time not elapsed MS send RR Statusmessage and no action taken

• If there is an error and start time has elapsed the MS aborts theconnection

Version 1 Rev 0Frequency Hopping to Enhance Network Capacity



2–16

Frequency Hopping to Enhance Network CapacityIn principle, implementation of frequency hopping system will not add extra capacity tothe existing network. Frequency hopping when implemented will enable more aggressivefrequency re–use pattern that leads to better spectrum efficiency. This enables thenetwork operator to add more transceivers in existing sites while maintaining the networkquality. In a congested network with fixed frequency plan, adding radios would meancompromising the carrier – interference ratio (C/I), which may lead to unacceptablequality level that may eventually crash the network if pushed to the limit. Thus, frequencyhopping is effectively “compressing” the available spectrum to make room for extracapacity, without degrading the average C/I as in a fixed frequency system.

In a cellular network, there is always a trade–off between capacity & quality. Maintainingthe current capacity, implementing frequency hopping will improve overall quality. On theother hand, extra capacity could be added by implementing frequency hopping whilemaintaining the current quality. However, realizing maximum gains in both quality andcapacity would not be achievable.

Version 1 Rev 0 Frequency Hopping to Enhance Network Capacity



2–17

Frequency Hopping to Enhance Network Capacity

Capacity

Quality

Capacity

Quality

Capacity

Quality

Capacity

Quality

Non–Hopping Hopping Hopping Hopping

sys12_ch02_08

Version 1 Rev 0Frequency Reuse Patterns



2–18

Frequency Reuse PatternsThe basic principle, cellular systems are based on, is the reuse of the frequencies inorder to obtain the highest capacity with the minimum spectrum. The more thefrequencies are used inside a certain coverage area, the more amount of traffic(capacity) can be carried. The possibilities of reusing the frequencies are limited byinterference problems arising when the same frequency is used in two cells that are tooclose each other (co–channel interference).

It can be considered that a cellular network is made up by a basic unit, in which all thefrequencies are used, repeated all along the area which is intended to be covered. Thisbasic unit (set of cells) is usually known as cluster, and it is the pattern used to deploythe network. The size of the cluster is directly related to the capacity that can beachieved. The smaller the size, the more times will be needed to be reused in thecoverage area, so the higher the reuse ratio and hence, the capacity.

The usual way to refer to a reuse pattern is by giving the number of cells included in thecluster as well as its configuration. In that way, a cluster made up by m sites with n cellsper site, giving a total of p = m*n cells, will be referred as “mxn reuse pattern”. Anyfrequency will be used once and only once inside the cluster.

As an example, a 12 cell cluster made up by 4 three–cell sites, known as 4x3 reusepattern, meaning that one frequency will be reused once each 12 cells or, equivalently,that 12 frequencies (one per carrier) will be needed to configure this cluster (a 4x3 reusepattern with, for instance, 3 carriers per cell would require up to 36 different frequencies).

Considering a conventional fixed frequency system in GSM, it has been agreed that a4x3 reuse pattern is the best compromise solution taking into account the co–channelinterference and the reachable capacity.

Higher capacity goals, without allocating more spectrum, lead to different techniques ableto control the interference and allow the system operator to use smaller clusters (tighterfrequency reuse patterns). Frequency hopping is the most efficient one, considering thevery small cluster size that can be achieved. As it will be described later in the document,a 3x3 reuse pattern can be successfully implemented in a system working with BaseBand Hopping.

More aggressive reuse patterns such as 1x3 (all the sites reuse the same set offrequencies) are possible in a system working with Synthesiser Frequency Hopping,although it must be noticed that with SFH more than one frequency can be assigned toeach carrier. This reduction in the size of the cluster, respect to the 4x3 one, can be usedto increase capacity. The results achieved in the systems already implemented using thatconfiguration prove its effectiveness to allow a very high capacity increase.

It is important to notice that, either for a fixed system or a Base Band Hopping system,the ratio Number of Frequencies/Number of carriers is always 1, whereas for aSynthesiser Frequency Hopping system, it can be higher than one. It is common to referto a SFH system as having a mxnxt reuse pattern, being t the number of frequenciesused to hop over. Sometimes, the ratio is intended to be noticed and they are named asmxn r/t reuse patterns (r carriers hopping over t frequencies). The number of frequenciesneeded to implement a cluster with that reuse pattern would be m*n*t.

As an example, the 1x3 2/4 reuse pattern uses 12 frequencies separated into threegroups of four frequencies each, and two carriers hop over these four frequencies. (A50% reduction in the number of frequencies required, respect to the fixed system thatcommonly uses a 4x3 reuse pattern).

Version 1 Rev 0 Frequency Reuse Patterns



2–19

Frequency Reuse Patterns

3x3 Frequency Reuse Pattern implemented with BBH

1x3 2/4 Frequency ReusePattern implemented with SFH

12 frequencies separated into three groups of fourfrequencies each, two carriers hop over these fourfrequencies – 50% reduction on 4x3 reuse pattern

Version 1 Rev 0Loading Factor



2–20

Loading FactorLoading Factor (or sometimes termed as Fractional load factor) is an importantparameter in SFH systems. It is calculated as:

loading factor = (highest non BCCH transceiver count in a cell)

(Number of hopping channels)

Since the number of frequency channels is always higher than the radio count in a cell,some channels will be idle at one time. Thus, loading factor is equivalent to the maximumchannel–occupancy to total–channel ratio in a cell at any given instant. The lower thevalue the lower is the channel loading, which indicates fewer collisions of frequencies andhence better quality.

A theoretical maximum of 50% is permitted in 1X3 SFH. Any value higher than 50%practically, results in unacceptable quality. Some commonly used loading factor are 40%,33%, 25% etc. In 1X1 SFH, a practical tested loading factor is 1/6 or 16.7%. For a roughcomparison, this is about equivalent to a 33% loading in 1X3 SFH or a well–planned4X3Xn fixed re–use network, as far as average quality is concerned. In terms ofspectrum utilization or capacity, 1X1 at 16.7% loading is equivalent to 1X3 at 50%loading.

Version 1 Rev 0 Loading Factor



2–21

Loading Factor

Loading Factor = (highest non BCCH radio count in a cell

(number of hopping channels)

non_ bcchbcch non_ bcchbcch

3 = 0.5 = 50%

6

sys12_ch02_09

Version 1 Rev 0Aggressive Frequency Reuse in SFH System



2–22

Aggressive Frequency Reuse in SFH SystemRe–use plan in a frequency hopping network is different and more aggressive than it is ina fixed frequency network for both BBH and SFH.

Most of the SFH networks employ two different re–use plans for the BCCH and TCHlayers. Since the BCCH will not be hopping, conventional fixed frequency re–use planssuch as 4X3 or 5X3 are normally used. It is always a design goal to have the cleanestfrequencies in the BCCH layer. As for the TCH layer, the common methodology would be1X3 (1 site 3–sector) re–use pattern. This is a much more efficient spectrum utilization,which is not possible in a fixed frequency system as the resultant C/I would be degradedbadly beyond � of the cell radius. An even more aggressive re–use plan 1X1 (1 site 1sector) is feasible in networks where the operating environment permits it. 1X1 is by farthe most efficient and yet practical aggressive re–use plan tested and proposed byMotorola. Nevertheless, careful planning has to be practiced to achieve good results. Theguidelines are outlined below.

Planning Guidelines for SFH

The ultimate goal of frequency planning in a GSM network is attaining and maintaining ahighest possible C/I ratio everywhere within the network coverage area. A generalrequirement is at least 12dB C/I, allowing tolerance in signal fading above the 9dBspecification of GSM.

The actual plan of a real network is a function of its operating environment (geography,RF etc) and there is no universal textbook plan that suits every network. Nevertheless,some practical guidelines gathered from experience can help to reduce the planningcycle time.

� Strongly recommended to have separate bands for BCCH and TCH. If micro cellsare included in the frequency plan then they also should have a separate band too.

� This makes planning simpler

� Allows better control of interference

� The use of IOS would be the most efficient way of working out a frequency plan,this means the frequencies would not be in separate bands but would be used intheir most efficient permutation.

Version 1 Rev 0 Aggressive Frequency Reuse in SFH System



2–23

Aggressive Frequency Reuse in SFH System

n channels m channels

BCCH TCH

Guard band

Macro BCCHMicro TCH

Macro TCH(SFH)

MicroBCCH

Version 1 Rev 0Planning Guidelines for SFH using 1x3 Frequency Reuse



2–24

Planning Guidelines for SFH using 1x3 Frequency ReuseThis page deals with some general guidelines for SFH using 1x3 frequency reuse plan,followed by an example.

� BCCH re–use plan: 4X3 or 5X3, depending on the bandwidth available andoperating environment.

� Divide the dedicated band for TCH into 3 groups with equal number of frequencies(N). These frequencies will be the ARFCN equipped in the MA list of a Hoppingsystem (FHI).

� Use equal number of frequencies in all cells within the hopping area. The allocationof frequencies to each sector is recommended to be in a regular or continuoussequence.

� Number of frequencies (N) in each group is determined by the design–loadingfactor (or carrier–to–frequency ratio).

� For example: mixture of 4–4–4 and 5–5–5 site configurations and loading factor of33%. Then N = 5 – 1/(0.33) = 15 frequencies in the MA list. As loading factor hasdirect effect on the overall network quality and its setting is highly dependent onthe RF environment, a smaller scale trial is recommended to obtain the necessarydata and experience before larger scale deployment. As a general rule, SFH with33% loading is equivalent to a well–planned 4X3 fixed frequency system.

� Use same HSN for sectors within the same site. Use different HSN for differentsites. This will help to randomise the co channel interference level between thesites.

� Use different MAIO to control adjacent channel interference between the sectorswithin a site.

SFH 1x3 Frequency Reuse Example

The example on the diagram opposite has a bandwidth of 10 Mhz, giving us 49 channelsof which the first and last are used as guard channels, so 47 usable channels. TheBCCH has 12 channels allocated to it in a 4x3 reuse pattern. It is a multilayerenvironment with 8 channels being allocated for the Micro layer.

The site configuration consists of a mixture of 2–2–2, 3–3–3 and 4–4–4 sites, with aloading factor chosen of 33%.

Version 1 Rev 0 Planning Guidelines for SFH using 1x3 Frequency Reuse



2–25

Planning Guidelines for SFH using 1x3 Frequency reuse

sys12_ch02_12

Bandwidth: 10Mhz(49 Channels – 2 Guard)Site configuration mixture of 2– 2– 2, 3– 3– 3 & 4– 4– 4.Loading factor 33 %Multi layer environment (micro & macro co–exist)

(highest non BCCH radio count in a cell) = No of hopping channels

loading factor4 – 1 = 9 hopping channels

0.33

Macro BCCHMicro TCH

MicroBCCH

Marco TCH(SFH)

8 channels

12 channels 27 channels

0, 2, 4Same as above23, 26, 29, 32, 35, 38, 41, 44, 47Sector C

1, 3, 5Same as above22, 25, 28, 31, 34, 37, 40, 43, 46Sector B

0, 2, 421, 24, 27, 30, 33, 36, 39, 42, 45Sector A

MAIOHSNARFCN

0, 2, 423, 26, 29, 32, 35, 38, 41, 44, 47Sector C

1, 3, 522, 25, 28, 31, 34, 37, 40, 43, 46Sector B

0, 2, 4Any from(1,2…63)21, 24, 27, 30, 33, 36, 39, 42, 45Sector A

MAIOHSNARFCN

The MAIO settings ensure that adjacent channel interference isavoided between sectors within the same site.

Co and adjacent channel interference between sites will exist,but the effect is reduced by the randomisation effect of thedifferent HSN

Version 1 Rev 0Planning Guidelines for SFH using 1x1 Frequency Reuse



2–26

Planning Guidelines for SFH using 1x1 Frequency Reuse1x1 frequency reuse is usually practical in rural areas with low traffic density, where theaverage occupancy of the hopping frequencies is low. With careful planning it can also beused in high traffic areas as well.

� BCCH reuse plan: 4x3 or 5x3, depending on the bandwidth available and operatingenvironment

� The allocation of TCH frequencies to each sector is recommended to be in aregular or continuous sequence

� Use a different HSN to reduce interference (co and adjacent channel) between thesites

� Use the same HSN for all carriers within a site and use MAIO to avoid adjacentand co–channel interference between the carriers. Repeated or adjacent MAIO arenot to be used within the same site to avoid co–channel and adjacent channelinterference respectively

� Maximum loading factor of 1/6th or 16.7% is inherent in a continuous sequence offrequency allocation. Since adjacent MAIO is restricted, the maximum permitted is:

Max MAIO = � x (Total allocated channel)

SFH 1x1 Frequency Reuse Example

In this example the configuration is 4/4/4 with a loading factor of 16.7%. Therefore thenumber of frequencies to hop through is 18. There are no repeated or adjacent MAIOand the HSN is the same within the site. Other sites would have a different HSN toreduce interference.

Version 1 Rev 0 Planning Guidelines for SFH using 1x1 Frequency Reuse



2–27

Planning Guidelines for SFH using 1x1 Frequency Reuse

sys12_ch02_14

Available Channels : 18Site configuration : 4–4–4.Loading factor : 16.7%

(highest non BCCH radio count in a cell) = No of hopping channelsloading factor

= 18 hopping channels0.167

4 – 1

sys12_ch02_15

1 7 13

3 9 15 5 11 17

HSN = 1

HSN = 1HSN = 1

Non adjacent MAIO toavoid adjacent–channel

Different MAIO to avoid co–channel

MA = 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38

MAIO restricted to 18/2 = 9

Version 1 Rev 0Comparisons between 1x3 and 1x1 Frequency Reuse Patterns



2–28

Comparisons between 1x3 and 1x1 Frequency Reuse PatternsBoth alternatives should be considered when SFH deployment is decided. The followingimportant aspects should be considered for comparison purposes:

Quality : The improvement in quality is the consequence of the frequency diversity andthe loading factor (ratio Frequencies/Carriers). Under the same conditions, the quality ofboth systems will be similar, but 1x3 reuse is more affected by irregularities in thenetwork. For an irregular network 1x1 system will perform with better quality.

Capacity : Considering the limitation of MAIO planning in a 1x1 system, and the loadingfactor, two situations can be found:

Totally regular network: If the implementation of 1x3 pattern is possible with 50% ofloading (good performance must be guaranteed), the capacity increase is the same thatcan be achieved with 1x1 pattern.

Irregular network: If 1x3 reuse pattern requires less than 50% of loading (40%, 33%, orlower), the 1x1 reuse pattern will permit higher capacity increase.

Frequency Planning : Frequency Hopping leads to a simplification in planning issue, anda reduction of manpower. In both cases, only BCCH planning requires a significant effort.For TCH planning with SFH the regularity of the network is very important . For regularones, 1x3 reuse is very simple because the three groups can be easily andsystematically assigned to the sectors without problems of interference. When thesectors are not evenly distributed omni or two–sector cells are present, etc. 1x3 reuserequires more effort to avoid interference, whereas 1x1 system does not require anyplanning effort at all.

Flexibility : The main advantage of Synthesiser Hopping appears at the time ofintegrating a new site, because of the simplicity of this task: Only a clean frequency isneeded for BCCH purposes, and the same frequencies used in all the sites will be reusedin the new one, following the reuse pattern. Provided that the network is regular, there isno difference between a 1x3 and 1x1 environments. For irregular networks it is easier tointegrate a new site in a 1x1 environment.

Expansion : When a new carrier needs to be added to an existing site, it is an easier taskin a 1x1 than in a 1x3 system. For the 1x3 system there will be a higher increase in theloading factor for the cell, so probably it is required a modification in the frequency groupsto tolerate the addition of the carrier without impacting the quality. For 1x1 case, providedthat the maximum number of carriers in the site was not reached before, it is easy toexpand the capacity with an extra carrier.

Version 1 Rev 0 Comparisons between 1x3 and 1x1 Frequency Reuse Patterns



2–29

Comparisons between 1x3 and 1x1 Frequency ReusePatterns

sys12_ch02_16

Quality– Regular

– Irregular

Capacity

Frequency Planning

Flexibility

Expansion

– Regular

– Irregular

– Regular

– Irregular

– Regular

– Irregular

Version 1 Rev 0Frequency Reuse in Baseband Hopping



2–30

Frequency Reuse in Baseband HoppingFor Base Band Hopping, since the number of frequencies to use in the hoppingsequence is determined by the number of carriers equipped, in order to be able toachieve the advantages of hopping, a system with high number of carriers per cell isrecommended (4 carriers per cell is a good value), and the higher this ratio the better theperformance enhancement achieved.

Alternative reuse patterns have been suggested to be implemented combined with BaseBand frequency hopping operation:

Progressive Reuse Patterns

Each new carrier added to a cell is equipped with the frequency reused in a more tightway:

1st TCH carrier: 4x3 reuse pattern

2nd TCH carrier: 3x3 reuse pattern

3rd TCH carrier: 2x3 reuse pattern

Homogeneous Reuse Pattarn

A more tight reuse pattern than the conventional 4x3 is used for all the TCH carriers,leading to the same gains achieved with the progressive reuse patterns for high loadedsystems. It also saves frequencies (available for other purposes, microcellular layer forinstance) in systems with few carriers per cell. Homogeneous 3x3 reuse pattern is theoption widely chosen to implement in some systems with very good performance results.

For comparative issues, considering a highly loaded system (4 or 5 carriers per cell)where BBH is expected to give more benefits, since all the calls spend part of its time ineach carrier, no difference should be noticed between both ways of reusing, buthomogeneous 3x3 reuse has the advantage that all the frequencies contribute equally tothe interference experienced by the calls (for Progressive Reuses the most tightly reusedfrequencies contribute more to the quality degradation), so, the effect of one carrier goingout of service is different for each TCH radio in a Progressive Reuse than in anHomogeneous one.

Planning Rules for BBH

The rules outlined for synthesiser hopping are generally applicable for baseband hopping.However as the BCCH is usually in the hopping frequency list, a dedicated bandseparated from the TCH band may not be essential. An example of a frequencyspectrum is shown on the PPT slide opposite.

Version 1 Rev 0 Frequency Reuse in Baseband Hopping



2–31

Frequency Reuse in Baseband Hopping

sys12_ch02_17

BBH channels & micro TCH

Micro BCCH

2nd TCH (2x3)

1st TCH (3x3)

BCCH (4x3)

Progressive re–use

2nd TCH (3x3)

1st TCH (3x3)

BCCH (3x3)

Homogeneous re–use

Version 1 Rev 0Capacity Gains for SFH and BBH



2–32

Capacity Gains for SFH and BBHTo give the reader a guide has to how frequency hopping can increase gain in a networkthe following examples to show the theoretical capacity gains for different frequencyreuse plans have been included. Of course these maybe different in the actual networkand the operating environment may restrict direct implementation of the re–use plan.

Example

In this example the operator has 7.2Mhz (or 36 GSM channels) of spectrum to use. Thetable on the PPT slide shown opposite shows the capacity per site for a fixed plan, BBHand SFH with different loading and frequency reuse. In all cases the calculations arebased on 2% blocking with 2 timeslots used for control channels in each sector.

Fixed Frequency: 22 TCH = 14.8959 from Erlang B tables3 sectors so 14.8959 x 3 = 44.7 Erlangs4x3 re–use with 9 channels per site so 9x4=36 channels

BBH: 30 TCH = 21.9316 from Erlang B tables3 sectors so 21.9316 x 3 = 65.8 Erlangs3x3 re–use with 12 channels per site so 12x3=36 channels

SFH (37.5%): 30 TCH = 21.9316 from Erlang B tables3 sectors so 21.9316 x 3 = 65.8 Erlangs12 channels for BCCH (4x3)Hopping channels = (highest non BCCH radio in a cell)

loading factor

8 = 3/0.375

1x3 re–use for SFH so 3x8 = 24 Total channels 12 + 24 = 36

SFH (50%): 38 TCH = 29.1661 from Erlang B tables3 sectors so 29.9316 x 3 = 87.5 Erlangs12 channels for BCCH (4x3)Hopping channels = (highest non BCCH radio in a cell)

loading factor

8 = 4/0.5

1x3 re–use for SFH so 3x8 = 24 Total channels 12 + 24 = 36

SFH (16.7%): 38 TCH = 29.1661 from Erlang B tables3 sectors so 29.9316 x 3 = 87.5 Erlangs12 channels for BCCH(4x3)Hopping channels = (highest non BCCH radio in a cell)

loading factor

24 = 4/0.167

1x1 re–use for SFH so 24 channels to hop throughTotal channels = 12 + 24 = 36

Version 1 Rev 0 Capacity Gains for SFH and BBH



2–33

Capacity Gains for SFH and BBH

97%87.55–5 –

4x3 (BCCH)1x1 (TCH)

SFH(16.7%loading)

97%87.55 –5– 54x3 (BCCH)1x3 (TCH)

SFH(50% loading)

47%65.84 –4 –4

4x3 (BCCH)1x3 (TCH)

SFH(37.5%loading)

47%65.84 –4 – 43x3BBH

44.73 – 3 –34x3Fixedfrequency

Capacity gainover fixed plan

Capacity per

97%87.55

4x3 (BCCH)1x1 (TCH)

SFH(16.7%loading)

97%87.54x3 (BCCH)1x3 (TCH)

SFH(50% loading)

47%65.84x3 (BCCH)1x3 (TCH)

SFH(37.5%loading)

47%65.83x3BBH

44.74x3Fixedfrequency

Capacity gainover fixed plan

Capacity perConfigurationReuse plan site ( Erlang )

Version 1 Rev 0Optimisation after Frequency Hopping Implementation



2–34

Optimisation after Frequency Hopping ImplementationAny modification to a network is initially accompanied by a performance change. Soimplementing a frequency hopping plan in a network that is already optimised wouldcertainly shift its overall performance, probably for the worse. Therefore postimplementation optimisation is crucial and necessary.

There are several methods of measuring network performance and comparing thembefore and after implementation:

� OMCR statistics – including key and health statistics

� CTP – analyse of measurement reports using call trace

� Speech quality – assess the received speech quality with subjective scores

� Drive test – drive around the test area and monitor the RF environment with a

test phone

Eliminate Non RF related issues

Optimisation

Neighbour List

dBase RF Hardware Frequency Plan

Version 1 Rev 0 Optimisation after Frequency Hopping Implementation



2–35

Optimisation after Frequency Hopping Implementation

MonitorPerformance

MonitorPerformance

Frequency HoppingImplementation



MeetsExpectationsMeetsExpectations

Take thecredit!!

Not meetingexpectationsNot meetingexpectations

Don’tpanic!

OptimisationOptimisation

Version 1 Rev 0Neighbour List Optimisation



2–36

Neighbour List OptimisationNeighbour list is a list containing all the information regarding the relationship that thesource cell has with its surrounding neighbour cells. It is the backbone of a GSM cellularnetwork and it forms the basis of mobility. Without a correct set of neighbour list, a GSMnetwork would collapse as many handover failures would occur and most calls would bedropped when the RF condition in the serving cell deteriorates beyond the limits.

There are 3 types of neighbour lists:

� Correct neighbour list.

� Incomplete neighbour list – neighbour cells that ought to be in the list are missing.This will eventually lead to high handover failure and dropped–call rate.

� Over complete neighbour list – Extra or weak neighbour cells being added orpresent in the neighbour list. This usually happens when the neighbour lists are notupdated after cells are added/removed or sites configuration (e.g. bore angle) arealtered. A call may be handed temporarily to a weak neighbour due to signal fadingand handed back to the original cell, seconds later. This creates a ping–ponghandover and some calls may be lost because the weak neighbour cell cannotmaintain them.

How to Detect

New valid neighbours can be added to an incomplete neighbour list by adding dummyneighbours to the cell dBase and analyse the Measurement reports (MR) using CTP orother equivalent tools. The mobiles served by this cell will be instructed to monitor thedummy neighbours’ frequencies and report the associated Rxlev in the MR. If there is avalid neighbour with BCCH frequency that is among the dummy frequencies, valid Rxlevand BSIC will be reported. The “Neighbour Analysis” function of the CTP can beconfigured to generate neighbours’ information (e.g. total number of MR reporting aparticular neighbour, % of MR reporting this neighbour with Rxlev exceeding certainconfigurable margin etc). If a neighbour is reported in significant % of MR with Rxlevexceeding preset margin, it may be considered a new valid neighbour and added in theneighbour list.

Weak neighbours can be detected with the “Neighbour Analysis” function of the CTP.With sufficient call trace data, the statistical analysis of the Rxlev of all the neighbourscan be studied. For example, the “Neighbour Summary” function generates summaryreport of all the serving cell/neighbour combinations. This summary gives:

The servers LAC, CI and its reported neighbours’ BCCH frequency and BSIC.

The total number of MR’s of the server and the number of MR’s reporting one particularneighbour.

The number of MR reporting each neighbour exceeding 3 preset thresholds and theassociated % figures.

Based on these statistics, neighbours that are not reported or reported with very weakRxlev or reported with low occurrence may be considered as extra neighbour and deletedfrom the dBase.

Version 1 Rev 0 Neighbour List Optimisation



2–37

Neighbour List Optimisation

sys12_ch02_20

Neighbour List Correct

Incomplete

Over complete

Dummy neighbours MR’s analysed by CTP

Version 1 Rev 0Database Optimisation



2–38

Database OptimisationThere are two important operations that are critical in a cellular system.

� Power control for MS and BTS

� Handovers

Power ControlPower control is the mechanism where the MS/BTS dynamically changes its transmitpower in order to maintain the receive level within certain pre–set limits. A closed loopmethodology is used base on:

� Receive level at MS/BTS

� Quality based, measures BER at MS/BTS

Recommendation s for hopping systems

alt_qual_proc = 0 (uses BER for receive quality processing)

decision_alg_type = 1 (Enables power increase based on quality)

mspwr_alg = 1 (uses enhanced PC algorithm for oscillation prevention)

pwrc = 1 (Do not include BCCH measurement for rxlev calculations)

As a result of frequency hopping and specifically interference averaging the overall BERwill be higher than non–hopping systems at the same perceived speech quality. Thus, theRxqual upper thresholds for PC may be set to values higher than they were in anon–hopping system.

HandoversIn a hopping system, handovers due to Rxqual and interference (intra–cell) behavedifferently from a non–hopping system. Due to the interference averaging effect, theaverage interference level in a hopping system is usually higher than before hopping isturned on. Therefore once hopping is turned on the number of handovers due to Rxqualmay increase significantly immediately after hopping is turned on and subsequentlyincrease the handover failure rate. So the handover thresholds and hreqave, hreqt haveto be modified to suit the new RF environment.

RXQUAL Hopping parametersThe hop_qual_enabled parameter enables or disables the use of specific rxqualthresholds for hopping call handovers.

chg_cell_element hop_qual_enabled [<lacation>] [,index] [,index] <value><cell_desc_opt>

System then prompts for

l_rxqual_dl_h_hopping

l_rxqual_ul_h_hopping

l_rxqual_dl_p_hopping

l_rxqual_ul_p_hopping

Values entered between 0 and 1810

Version 1 Rev 0 Database Optimisation



2–39

Database Optimisation

Interference averaging has an effect on:

Rxqual – Power control settings

Handover control settings

chg_cell_element hop_ qual_enabled [<location>] [,index]<value> <cell_ desc_opt>

l_rxqual _dl_h_hopping

l_rxqual _ul_h_hopping

l_rxqual _dl_p_hopping

l_rxqual _ul_p_hopping

Values 0 –1810

Version 1 Rev 0RF Hardware Optimisation



2–40

RF Hardware OptimisationAlterations to the physical RF hardware are sometimes the unavoidable actions neededin cellular optimisation. There are in general four types of cell coverage that areundesirable in a cellular network:

� Umbrella cell – a very high site (e.g. on a hill) that has a very wide coverage areaand has “line of sight” (LOS) to cells that are located far away. It poses seriousinterference problem, especially in a 1X3 or 1X1 SFH system that has high radiocount.

� Splash or island – Spilt–over or over–shot coverage of one cell to itsneighbouring cells and usually not reciprocal. This is similar to umbrella cell butsplash–over is usually localised within a few spots instead of a continuous largearea.

� Overlap – undesirable high level of reciprocal coverage overlap between 2neighbouring cells.

� Void – coverage holes that exist due to no dominant cell.

In a frequency hopping system, all of the above cell coverage affect RF quality and ifexist must be rectified as soon as possible. This is especially critical in SFH system withirregular sector orientation, where the re–use pattern is much tighter and collisionprobability is higher.

How to detect

To detect an umbrella cell is straight forward as it is always a very high site (e.g. on asmall hill) and simple drive test will prove its “over stretched” coverage into other cells.

Splash or island interference is usually localized within small spots. It is alsonon–reciprocal, meaning the interference effect is one way, i.e. from the interfering cell toits neighbours and not the other way round. CTP or drive test can be used to detectisland or splash. The distinctive characteristics are:

Sudden emergence of the interfering cell as a strong neighbour and may temporaryserve a call.

A dual–peak distribution of timing advance may be observed in the interfering cell. Thepeak at higher end can be attributed to the island of splash spots located distant awayfrom serving area of the cell.

Overlapping is reciprocal interference where the effect on the overlapped cells ismutual. CTP or drive testing can be used to detect overlaps with the following distinctivecharacteristics:

The overlapped neighbours will be reported within low margin from the server Rxlev, in asignificant high number of measurement reports (MR).

High occurrence of HO between the cells within the overlapped area.

Drive testing or CTP can easily detect void in coverage. In any case, there will be aconsiderable number of MR reporting very low Rxlev of the server and its neighbour.

Version 1 Rev 0 RF Hardware Optimisation



2–41

RF Hardware Optimisation

sys12_ch02_21

SuggestionProblem

Umbrella cell

Island/splash

Overlapping

Void

Replace siteReduce number of carriersModify frequency planDown tilt, antenna type, transmit power.

Antenna heightDown tilt, antenna typeTransmit power

Frequency planAntenna heightDown tilt, antenna typeTransmit power

Add siteSector orientationTransmit power, antenna type

Version 1 Rev 0Frequency Plan



2–42

Frequency PlanAfter a frequency plan has been designed there maybe times when for various reasons itwill need to be modified. On this page are a three examples of different situations wherea change is required.

An umbrella cell with high transceiver count. If some spare channels are available, theymay be added to or used to replace a few channels in the existing MA. This in effectreduces the channel occupancy of the original frequency plan, and hence lowers thefrequency collision rate.

Cells at the boundary of hopping and non–hopping systems. There are usuallyinterference problems at the boundary of two different frequency plans. As explainedabove, some spare channels will be handy in reducing the interference. If no channelsavailable for spare, swapping the frequency between the sectors within a hopping sitemay be a 2nd alternative.

Areas with no dominant server and served by several cells. This is critical especially in anetwork with irregular sector orientation. Introducing spare channels or swappingchannels between cells, as explained above, may be effective in reducing the averageinterference level.

Version 1 Rev 0 Frequency Plan



2–43

Frequency Plan

InterferenceInterference34,10,14

24, 2, 5, 8,11

28, 3, 6, 9, 12

20,1, 4, 7,10

Non Hopping Hopping Spare Channel 18

34,10,14

24, 2, 5, 8,11

28, 3, 6, 9, 12

20,1, 4, 7,10

34,10,14

24, 2, 5, 8,11

28, 3, 6, 9, 12

20,1, 4, 7,10

34,10,1434,10,14

24, 2, 5, 8,11

28, 3, 6, 9, 12

20,1, 4, 7,1024, 2, 5, 8,11

28, 3, 6, 9, 12

20,1, 4, 7,10

Non Hopping Hopping Spare Channel 18

Swap with 11 or replace with 18Swap with 11 or replace with 18




2–44

Version 1 Rev 0 Frequency Plan



2–45

Frequency Plan

ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ

24, 2, 5, 8,11

28, 3, 6, 9, 12

20, 1, 4, 7,10

24, 2, 5, 8,11

28, 3, 6, 9, 12

24, 2, 5, 8,11

28, 3, 6, 9, 12

20, 1, 4, 7,10

Main Road

ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ

Interferencearea

20 1, 4, 7,10




2–46



3–1

Chapter 3

Deployment of Microcellular

Version 1 Rev 0



3–2

Version 1 Rev 0 Deployment of Microcellular



3–3

Deployment of Microcellular

Objectives

On completion of this chapter the student will have:

� Discussed the deployment of microcells.

� Discussed idle mobile behaviour in microcells.

� Discussed the techniques employed in microcells.

� Discussed the principles employed in providing in–building coverage.

Version 1 Rev 0Introduction to Microcellular



3–4

Introduction to Microcellular

At present, 80% to 90% of the current GSM subscribers fall into one category, that ofslow moving and stationary mobile stations.

Microcells address this category of subscriber by providing increased quality of servicethrough reduced blocking and greater coverage in built up areas.

What are microcells?

The microcell is a reduced power cell intended for use in dense traffic environments,such as cities or possibly within public buildings. The microcell has its antenna(s) belowrooftop level and usually at least 5m above street level. The main region of operation forthe microcell is the street canyon.

Microcells typically have a radius of 200–300 metres and exhibit transmission behaviour,which differs from conventional large or small cells. Propagation is primarily “line of sight”and radio path loss increases sharply as the receiver moves out of sight of thetransmitter.

Microcells differ greatly from the conventional macrocell, which provides ‘umbrella’coverage over a wide area, by providing focused coverage and capacity over all or partof the macrocell coverage area. Microcells offer improved propagation properties,experience less severe fading.

The street canyon

Radio signals from a microcell to a hand portable unit of street level travel by reflectionand diffraction from buildings and other street furniture, but principally by line of sight.Usually the antennas of microcells are so positioned that only negligible amounts ofradiation escape over the rooftops. The microcell’s functions are almost isolated withinthe street canyon. Propagation loss rises steeply when the hand portable moves out ofthe line of sight (around the street corner). The street canyon is effectively a sealedenclosure, albeit with somewhat different propagation characteristics.

RF considerations

By using microcells areas that have previously been unreachable by macrocells can nowhave RF coverage. Microcells also allow a much tighter reuse of the available RFspectrum.

Microcell applications

Microcellular is a system that has applications in:

� Hotspots

� Dense urban areas (contiguous coverage)

� In–building systems.

Version 1 Rev 0 Introduction to Microcellular



3–5

The Street Canyon

sys12_ch02_01

RF SignalStreet Canyon Effect

Microcells provide RF coverage previously unreachable by Macro

Allows tighter reuse of frequencies

Antenna(s) situated below rooftop levels

Propogation primarily line of sight

Version 1 Rev 0Multi–Layered System



3–6

Multi–Layered SystemIn the Motorola multi–layer network approach, a complete microcellular network isdeployed under the existing macrocell network. Cells of different sizes are overlaid, andbase stations with different transmit power levels co–exist in close proximity.

The wide coverage area with high–powered macrocells is considered as the Overlaynetwork. The macrocells will provide wide coverage and act as a “safety net” for mobilesmoving between microcellular areas. The low powered microcells that are installed withinthe high traffic areas of the network can be considered as the Underlay network.

Through the right choice of the microcell site locations, an improved and flexiblecoverage may be provided, increasing the capacity through tighter frequency re–use andsmaller cell sizes. This is possible due to the street canyon effect dominating the RFpropagation. With a proper location of the antennae (6 metres to 2/3 the height of thebuilding) the coverage provided is constrained by the surrounding buildings and there–use pattern can be much tighter as the inter–micro interference can be controlled.

Re–use patterns of 3 x 1 (three frequency sets for the whole two carriers system) havebeen implemented in some systems over the entire microcellular portion of the network,by making use of the flexibility Motorola’s software provides.

When planning for our multi–layered system we have to plan that micro/picocells willcover the large majority of subscriber density. The mobiles will be slow moving. Thereforewe could have a three–layered system.

Macro: Supporting fast moving mobiles. Also support for congestion in micro/pico layers and for bad quality in micro/pico layers.

Micro: Supports slow moving mobiles down at street level (outdoor environment), therefore reducing congestion where large subscriber density is found. For inbuilding coverage using micro cells can give better coverage using external penetration.

Pico: Where good coverage and good quality of signal is needed within a building containing a large subscriber density, then pico cells can be set up as a third layer to support this.

Version 1 Rev 0 Multi–Layered System



3–7

Multi–Layered System

sys12_ch02_03

Macro Layer: Fast moving mobiles

and umbrella coverage

Micro Layer: Support of slow

moving mobiles at street level

Pico Layer: Support of inbuilding

solution

Version 1 Rev 0Deployment Strategies



3–8

Deployment StrategiesAfter many systems deployed, it has been easy to identify in which situations weimplement microcells and what are the configurations to cope with them. There aretypical situations where microcells are deployed:

Capacity relief in hot–spot locations :

Traffic is concentrated and produces blocking in certain cells. In this situation microcellsare planned to put the capacity where needed. At the same time, coverage and qualityare improved to the high number of subscribers generating the traffic, without introducinginterference to the rest of the system, as it would be done by adding new radios to themacrocells (assuming this would be possible).

Capacity relief in saturated areas (business areas, commercial centres, etc.)

Macrocellular expansions are difficult to plan there as the system has reached itsminimum cell size. There are not frequencies available for adding new radios in macrostations and even if that would be possible, they would not provide the erlang densityrequired.

In–building coverageIncreasing the coverage area does not necessarily imply increasing the geographic areaof coverage. Improving in–building coverage within the existing coverage area is one ofthe uses of microcells. A picocell could be designed to cover a specific buildinginternally.

Easy capacity expansion system wide as the number of subscribers increases

The system is mature, and the cell radius is minimum. High capacity solutions must beused. Other solutions are short term, as they do not provide the same capacity andquality. Sometimes they are difficult to implement, more expensive, and do not haveextra values added as the quality and coverage improvement, the better in buildingpenetration, the lower interference added, the longer mobile battery life, etc.

In a Macro–Micro Layered System these are the typical configurations implemented tocope with the situations exposed above:

Isolated microcellsDeployed in hotspot locations coping with specific capacity requirements in a certainarea. These microcells would re–use frequencies from the macro layer, and microcellularalgorithms are only used to go down from the macro layer.

Sparsely connected microcellsThese are loosely interconnected microcells. This is the natural system growth fromhot–spot configuration. This configuration covers capacity problems in a certain area. Inthis configuration microcellular algorithms are used not only to go down from the macrolayer but also to perform handovers between microcells.

Contiguous microcellular network underlaying the standardmacrocellular system.In this case a dedicated part of spectrum for the microcellular network is desired, even ifnot entirely necessary. Microcellular algorithms will be needed to maintain the call in themicro layer and to address specific scenarios that appear in the new propagationenvironment (antennas below roof level and street canyon propagation effect).

Version 1 Rev 0 Deployment Strategies



3–9

Deployment Strategy

sys12_ch02_04

HighSubscriberArea

ContiguousSystem

Hotspots

Cluster

Version 1 Rev 0Combined cell handovers



3–10

Combined cell handovers

Within a combined cellular network the microcellular layer is biased to be dominantbecause the majority of calls will take place on the microcells that offer a much higherquality of service. Only under certain conditions when that normally high level of servicecannot be maintained does control pass to the macrocellular part of the combinednetwork.

The macrocellular network functions separately from, but in conjunction with, themicrocellular network. As long as a mobile moves at relatively low speeds within thearea served by the microcellular network, communication is via the microcell offering thebest quality of service. As long as a faster moving unit continues to move above acertain speed, communication is via the overlaying macrocell, because in this instanceonly the macrocellular part of the network can offer the higher quality of service underthese conditions.

However, when a signal level from the mobile subscriber equipment at a microcellindicates that a better quality of service can be offered by an overlaying macrocell (suchas when a subscriber moves towards X in the diagram opposite), and this conditionpersists, handover to the overlying macrocell occurs.

This condition would also occur on emergence from microcellular coverage, atmicrocellular blackspots and with rapid increase of speed, (such as a car starting fromtraffic lights at Y and accelerating towards Z. In these cases the macrocell acts as asafety net for the overlaid microcells.

Version 1 Rev 0 Combined cell handovers



3–11

Combined Cell Handovers

SYS102_ch04_05

X

Hand upto macrolayer

Y

Z

Hand upto macrolayer

Macrocell

Version 1 Rev 0Hotspots



3–12

Hotspots

Hotspots are easier to implement than contiguous microcell coverage. Hotspots can beimplemented in areas of high traffic density where the use of either a microcell or theutilization of existing hardware and software is purely employed to relieve the loading ofthe macrocell.

As the coverage is non–contiguous and the RF hardware employed is effectively astandalone cell, the frequency planning is relatively easy.

Hotspots handovers

As a hotspot is in an area of high traffic density then presumably most of the subscriberswould be very slow moving or stationary. It would be unwise to place a microcell as ahotspot if its coverage extends onto a road or railway. Cell location is critical to ensureefficient use of carrier resource.

Handovers to/from hotspot cells

There are a number of possibilities open to the planner when configuring hotspot cells.Two basic considerations are whether handovers into the cell are allowed from themacrocells, or they are disabled.

Handovers to the hotspot cell

If desired, it is possible to disable hand–ins to the hotspot cell in order to tailor the cell foroptimal handling of local mobiles. Consider the case, for example, where the hotspot cellprovides extra coverage (and hence picks up extra traffic) compared to the macrocell(e.g. with an in–building hotspot cell).

There is always the danger that the hotspot cell coverage will extend out of the buildingand maybe onto a busy road. This cell will then pick up traffic from the road that couldotherwise have been handled by the macrocell serving that area. This traffic is served atthe expense of in–building capacity. The traffic carrying capacity of the cell is thereforenot being used optimally.

Additionally, if fast moving mobiles successfully hand in to the hotspot cell, there is adanger that due to their speed the hand out may fail causing the call to be dropped.

If there is no danger, due to spurious coverage, of the hotspot cell picking up mobileswhich should have been handled by the macrocells then hand–ins and hand–outs to thehotspot cell should be enabled.

Care should be taken with the use of adjacent channels in the hotspot cell and theoverlying macrocell. Potentially, there are situations where this may work, for example, ifthe area contains only slow moving traffic. Then, handovers may be fast enough toprevent adjacent channel interference from happening (disabling hand–ins would not beallowable in this case).

Version 1 Rev 0 Hotspots



3–13

Hotspots

SYS102_ch04_06

MacroMacro

High TrafficDensity

Micro orutilisation ofexisting hardwareand software

Frequency Planning Simple

Used for Slow Moving Traffi

Handovers Not Allowed for Fast Moving Traffic

RoadRoad

Handovers Allowed for Slow Moving Traffic

�

�

�

�

Version 1 Rev 0Controlling Handovers in Hotspots



3–14

Controlling Handovers in Hotspots

The microcellular handover procedures developed for use in the combined cellarchitecture (see microcellular database parameters) can also be used to controlhandovers to/from hotspot cells. However, there is also scope for using the parametersin the “standard” algorithms to adjust the handovers as required.

Two methods may be:

� Make the hotspot cell difficult to hand into or reselect by fast moving MSs.

� Ensure that fast handover from MS leaving the hotspot cell is encouraged.

Fast moving MSs entering a hotspot

Fast moving MSs selecting the hotspot cell run the risk of dropped calls should theyoriginate a call. There is also a risk of fast MSs dropping calls should they enter the cellin dedicated mode.

To discourage fast moving MSs from handing into the hotspot cell in dedicated mode,there are 2 mechanisms (apart from disabling incoming handovers). These options areto increase the handover margin and/or to increase the averaging time in the macrocell.

The handover margin is definable on a per neighbour basis and therefore can beincreased for handovers to the hotspot cell, and left as it was for the macrocell’s otherneighbours.

The averaging time defined by hreqave is now definable on a per cell and per neighbourbasis and therefore increasing it will affect handovers into the hotspot cell.

MSs leaving a hotspot

Given the typical environment of a hotspot microcell, MS leaving the cell will oftenattempt to hand out of the cell after they have turned a corner. There is often a veryrapid drop of signal strength (20dB or more) on turning the corner. The system designshould be such that;

� this drop is recognized and a handover command generated.

� the hotspot signal strength should be sufficient for the MS to receive the handovercommand correctly.

It is highly likely that, at the point where the hotspot cell signal experiences a rapid drop,the macrocell will be significantly stronger after the drop. Therefore a high value ofho_margin can be used. The averaging period, defined by hreqave , however, should beset to a short value, allowing a fast handover. Another possibility is to trigger thehandover on downlink rxlev , again with a short averaging period.

Version 1 Rev 0 Controlling Handovers in Hotspots



3–15

Controlling Handovers in Hotspots

sys12_ch03_08

Macrocell

Hotspot Cell

Fast moving MS Fast moving MSFast moving MS

Fast

moving MS

hreqave (high value)

Macrocell (per neighbour) Hotspot cell (per neighbour)

ho_margin (high value)

rxlev_min_cell (high value)

hreqave (low value)

Version 1 Rev 0Idle Mobile Behaviour



3–16

Idle Mobile Behaviour

Idle mobiles are constantly listening to the BCCHs of its serving and surrounding cells toenable it to setup a call on the most appropriate cell when required. How a mobile unitbehaves in idle mode is more loosely specified by the GSM recommendations. This hasthe consequence that mobiles from different manufacturers may behave differently.

Association of mobiles to micro/macro layer

A basic philosophy may be to keep all idle mobiles camped onto the macrolayer and thento drop them to the microlayer on call setup.

The problems which can occur if this is not done, are caused by the fact that the mobilescell reselection process may be too slow to avoid loss of service. A fast moving mobilecamped on a microcell will, if it does not reselect quick enough, experience downlinkinterference and loss of the downlink CCCH. Slow reselection and interference on thedownlink can result in lost pages.

There is also the option of doing nothing. Letting the mobiles originate on their bestserver, micro or macro, will result in most mobiles originating on the microlayer. This willincrease system capacity but will cause problems with fast mobiles.

The operator must decide which gives the best overall system performance:

Maximizing capacity with freely allowed origination

OR

Best performance for fast mobiles with restricted originations.

Of course the problem of fast moving mobiles may not occur.

Version 1 Rev 0 Idle Mobile Behaviour



3–17

Idle Mobile Behaviour

sys12_ch02_09

Macrocell

Hotspot Cell

Fast moving MS Fast moving MSFast moving MS

Fast moving mobiles in idle mode may:

Originate or reselect onto hotspot cell, or

Excluded unless fulfilling criteria

FastMovingMS

Version 1 Rev 0Methods of controlling reselection into a cell



3–18

Methods of controlling reselection into a cellBefore considering the use of separate BA lists to control reselection into a cell we shalllook at the effect of changing the database parameters rxlev_access_min andcell_reselect_hysteresis. The example opposite shows the effect of increasing thevalue of rxlev_access_min in the hotspot cell. The obvious disadvantage of increasingthis parameter is that the MS will be discouraged from selecting into the cell until it isquite near the antenna. Another possibility would be to use cell_reselect_hysteresis todiscourage reselections. The disadvantage would be having set the hotspot as aseparate location area.

C1 is calculated by MS P1 and P2 are broadcast on BCCH.

C1= (A – MAX (B, 0))

A:= Rxlev Average – P1

B:= P2 – Max RF Power of Ms

P1 = rxlev_access_min=<*>

0= –110 dBm1= –109 dBm..63= –47 dB

P2= ms_txpwr_max_cch= <*>

0= 43 dBm1= 41 dBm..15= 13 dBm

Note:+A – Good downlink–A – Poor downlink+B – Poor uplink–B – Good uplink

A brief description of C1 would be:

– for selection the MS chooses the best positive C1 value.

– for reselection the C1 value of the neighbour must be greater than that of the server.

cell_reselect_hysteresis= <*>

* 0= 0dB RXLEV1= 2dB RXLEV..7= 14dB RXLEV

Altering this parameter will make reselection into other macros delayed.

Version 1 Rev 0 Methods of controlling reselection into a cell



3–19

Cell Reselection for Fast Moving Mobile Units

sys12_ch02_10

Macrocell

rxlev_access_min = 6 ( –104 dBm)ms_txpwr_max_cch = 5 (33 dBm)cell_reselec_hysteresis = 4 (8 dB)

Hotspot Cell

rxlev_access_min = 40 ( –70dBm)ms_txpwr_max_cch = 5 (33dBm)

–70 dBm

– 60 dBm

P = 4 (33dBm)P = 4 (33dBm)

C1 calculation for macro cell

C1 = (A – MAX(B,0)

A = –70 – (–104) = 34

B = 33 – 33 = 0

C1 = 34 – 0 = 34dB (if reselection + 8 = 42 dB)

C1 calculation for micro cell

C1 = (A – MAX(B,0)

A = –60 – (–70) = 10

B = 33 – 33 = 0

C1 = 10 – 0 = 10dB

Loc B

Loc A

Loc B

Loc A

Version 1 Rev 0Cell reselection C2



3–20

Cell reselection C2

C2 can be used to control mobiles from reselecting into the microcell by setting a timethat the mobile must be in receipt of the microcell or macrocell neighbours BCCH beforeit can camp on, it could also reduce the number of reselections. This parameter is onlyapplicable to phase 2 mobiles, phase 1 mobiles use C1.

C2 is an optional GSM feature which can only be used for cell reselection, it can beenabled or disabled on a cell basis. If C2 parameters are not being broadcast the C1process is used for reselection. The formula below shows that C2 is firmly based on theoriginal C1 calculation.

C2= C1 + Cell_reselect_offset – Temporary offset * H (for penalty_time <31)

C2= C1 – Cell_reselect_offset (for penalty_time= 31)

H = 0 for (penalty_time – T) < 0

H = 1 for (penalty_time – T) > 0

Whilst idle the mobile will maintain a list of the strongest 6 neighbours being monitoredfrom the idle ba list. This will be constantly updated and reselection parameters regularlychecked. At least every 5 seconds the MS will calculate C2 for the server and C2 forneighbours, if the C2 for the best neighbour exceeds that of the server for a period of 5seconds then reselection will take place. If the neighbour is in a different location areathen cell_reselection_hysteresis is also considered for the same period.

The parameters affecting C2 are broadcast on BCCH system information to an idlemobile and are described below:

cell_reselect_param_ind = <*>

This parameter is used by the MS to determine if C2 parameters are being broadcast ornot. If set the MS will use the C2 process for reselection, otherwise C1 controlsreselection as well as selection.

<*> 0 – C2 parameters not broadcast

1 – C2 parameters broadcast

cell_reselect_offset = <*>

An integer code specifies the cell_reselect_offset in dBs. This offset could be eitherpositive or negative depending on the value of penalty_time .

<*>0 = 0dB

1 = 2dB

.

63 = 126dB

Version 1 Rev 0 Cell reselection C2



3–21

Cell reselection C2

sys12_ch02_11

Macrocell

C1 = 20dB

Hotspot Cell

C1 = 30dB

cell_reselect_param_ind = 1penalty_time = 1 (40s)cell_reselect_offset = 10 (20dB)temporary_offset = 4 (40dB)

MS passesthrough cell in

T = 30s

C2 = C1 + cell_reselection_offset – temporary_offset x H

Unless penalty_time = 31 then

C2 = C1 – cell_reselection_offset

H = 1 as penalty_time – T > 0 (40 – 30 = 10)

C2 = 30 + 20 – 40 x 1 = 10dB

If the mobile is stationary

H = 0 as penalty_time – T < 0 (40 large = neg)

C2 = 30 + 20 – 40 x 0 = 50dB

Will not select as less than macro C1Will select as more then macro C1

Version 1 Rev 0Cell reselection C2 – Continued



3–22

Cell reselection C2 – Continued

A brief description of C2 would be:

� For reselection to take place within a location area.

C2 (server)<C2 (neighbour) for penalty_time

� For reselection to take place to another location area.

C2 (server)<C2 (neighbour) for penalty_time (note: C1 calculation for theneighbour will still take cell_reselect_hysterisis into account)

temporary_offset = <*>

This negative temporary_offset is imposed only for the duration of the penalty time,then it is disregarded.

<*>0 = 0dB

1 = 10dB

.

7 = infinity

penalty_time = <*>

penalty_time is the duration for which the negative temporary_offset is considered, andis compared with Time T in the algorithm. Time T is the length of time the MS hasmaintained the neighbour in its top six measured cells. If penalty_time is set to 31 thetemporary_offset is ignored and the cell_reselect_offset becomes constantly negative.

<*>0 = 20 sec

1 = 40 sec

.

30 = 620 sec

31 = temporary_offset ignored, cell_reselect_offset is negative

cell_bar_qualify = <*>

cell_bar_qualify is used only in cell selection to prioritise a cell as being “normal” or“low” priority. The MS will always select cells with normal priority providing their C1calculation is greater than zero. Only if a “normal” priority cell cannot be found will a“low” priority cell (providing C1 > 0) be selected. This is a phase 2 mobile function.

<*>0 – normal

1 – low

Version 1 Rev 0 Cell reselection C2 – Continued



3–23

Version 1 Rev 0Selective cell–bar on microcells



3–24

Selective cell–bar on microcells

An alternative approach is to selectively cell–bar the microcells. This means that mobilesin idle mode may only camp on the macrocells. Origination would occur on the macrocell,followed by hand–down to the microcell if appropriate.

This approach, however, has the disadvantage that any extra geographical coveragewhich barred microcells offer over and above that of the macrocells would be lost as faras originations were concerned. This situation could be alleviated to some extent by notbarring indoor and pedestrian area microcells or areas of macrocell deep fade.

Selective cell bar is set in add_cell and is set by the prompt cell_bar_access_switch .

cell_bar_access_switch= 0

– cell is not barred

cell_bar_access_switch= 1

– cell is barred

Emergency calls (user class 10) are not, and cannot be, barred.

An MS decodes the BCCH data to determine if it is allowed access to the system. BCCHdata includes information which indicates that the cell transmitting the data is part of theselected PLMN (unbarred) or not (barred).

Version 1 Rev 0 Selective cell–bar on microcells



3–25

Selective Cell–Bar

Macro

cell_bar_access_switch = 0

Micros

cell_bar_access_switch = 1

MS selects ontomacro

sys12_ch02_12

Version 1 Rev 0Selective cell–bar on microcells



3–26

C2 reselection exercise

The parameters and levels specified on the facing page are typical values experiencedby a mobile in the reselection process. Use these values to determine whether themobile will reselect to the neighbour cell. The mobile has been in the server well overone hour, and the best neighbour has been in the top six measured cells for exactly 4minutes.

WORKING AREA

SERVING (working out C1 first)

A= Rxlev Av – P1 P1= rxlev_access_min = dBm)

A= – = dB

B= P2 – Max RF Power of MS (P2= ms_txpwr_max_cch = dBm)

B= – = dB

C1= – = dB

C2= + = dB

NEIGHBOUR

A= Rxlev Av – P1 (P1= rxlev_access_min = dBm)

A= – = dB

B= P2 – Max RF Power of MS (P2= ms_txpwr_max_cch = dBm)

B= – = dB

C1= – = dB

C2= + – = dB

� ��

��

Version 1 Rev 0 Selective cell–bar on microcells



3–27

C2 Reselection Example

� SERVING CELL DATABASE PARAMETERSCELL IDENTITY= 234 10 255 038

rxlev_access_min= 20 (–90dBm)

ms_txpwr_max_cch= 7 (29dBm)

cell_reselect_param_ind=1

cell_reselect_offset= 3

temporary_offset= 3

penalty_time= 5

� BEST NEIGHBOUR CELL DATABASE PARAMETERSCALL IDENTITY = 234 10 262 042

rxlev_access_min= 20

ms_txpwr_max_cch= 5 (33dBm)

cell_reselect_param_ind=1

cell_reselect_offset= 2

temporary_offset= 1

penalty_time= 12

� �&��$ �$� ��

�� $��

�!" ��# � ��

� �� !��"��'!"� �!�!� �

� �� %� ��!!� � ��% ≈ ��

Version 1 Rev 0Effects of Broadcasting Separate BA Lists



3–28

Effects of Broadcasting Separate BA Lists

Broadcasting separate BA lists

The separate BA lists feature allows the operator to select neighbours to be included inthe BCCH allocation on the SACCH and the BCCH.

� BA BCCH: This list is the BA sent in the System Information Message Type 2 onthe BCCH. It is the list of BCCH frequencies in use by a PLMN in a givengeographical area. It is used by the MS in cell selection and re–selection.

� BA SACCH: This list is the BA sent in the System Information Message Type 5 onthe SACCH. It indicates to the MS which BCCH frequencies are to be monitoredfor handover purposes.

By maintaining two distinct BA lists, the operator is given the flexibility to vary thefrequencies the MS monitors in idle mode independant of the frequencies the MSmonitors as potential neighbours in active mode.

Method 1: (see table opposite)

With this arrangement, there is no restriction on handovers, they can occurmacro–macro, macro–micro, micro–macro, and micro–micro. However, when a mobilewhich is camped on a microcell moves out of this cell, it can only reselect a macrocellsince this is all there is in its BA(BCCH) list.

Method 2: (see table opposite)

Method 2 is similar to method 1 except that the microcells are removed from themacrocell BA(BCCH), resulting in there being no reselection mechanism to return to themicrocells once the macro layer is entered. This would place a large amount of idlemode traffic on the macrolayer. This traffic would place call originations on themacrolayer and hand down to the microlayer would then follow where appropriate.

This strategy could be used in the case where there are fast moving mobiles and theslow reselection process and downlink interference would cause lost CCCH – lost pages.

Version 1 Rev 0 Effects of Broadcasting Separate BA Lists



3–29

Broadcasting Separate BA Lists

sys12_ch02_14

Method 1

Method 2

Microcell BA(BCCH) Overlying macrocell

Microcell BA(SACCH)Overlying macrocellsNeighbour microcells

Macrocell BA(BCCH)Neighbour macrocellsUnderlying microcells

Macrocell BA(SACCH)Neighbour macrocellsUnderlying microcells

Broadcast Broadcast candidates listed

Microcell BA(BCCH) Overlying macrocell

Microcell BA(SACCH)Overlying macrocellsNeighbour microcells

Macrocell BA(BCCH) Neighbour macrocells

Macrocell BA(SACCH)Neighbour macrocellsUnderlying microcells

Broadcast Broadcast candidates listed

Version 1 Rev 0The layered Approach



3–30

The layered ApproachLet us compare the picocellular environment with that of the microcellular solution.

Within the microcellular area of coverage we had a small cell of less than 500m radius,with the antenna mounted below rooftop. This enabled the RF to be contained withinstreet canyons. This provided additional capacity, as well as efficient reuse of the portionof the frequency spectrum allocated to operators.

The picocellular area of coverage is a small cell of less than 100m radius with theantenna mounted inside a building. However, the RF environment is now containedwithin the building, thereby providing additional capacity as well as a high frequencyreuse.

Picocellular can be considered as the third layer within a multi–layer network.

The picocellular solution provides this functionality of a seamless service within theexisting infrastructure by utilising the same phone, same features, as well as the samemethod of accessing these features in all environments.

There must also be the seamless service between the three layers:

Layer 1 – macrocell

Layer 2 – microcell

Layer 3 – picocell

as well as the support of the mobile in both the idle and dedicated mode.

Version 1 Rev 0 The layered Approach



3–31

The Layered Approach

Macrocell

Microcell Picocell

Version 1 Rev 0BA Lists Exercise



3–32

BA Lists ExerciseIf it was decided that we would like the mobile just to camp on to the macro layer in idlemode, and not on the micro cell layer (handovers to take place between layers) howwould we set up the neighbour list in the micro and macro serving cells?

For the in–building solution we want the mobiles to reselect to the pico cell in the lobbyfrom the macro when entering the building, but once in the building, we do not want toreselect back to the macro. How would we set the neighbour list for the pico cells andmicro cells?

Version 1 Rev 0 BA Lists Exercise



3–33

BA Lists Exercise

sys12_ch02_15

Macro

Cell 1

Macro

Cell 1

Micro

Cell 2

Micro

Cell 2

Pico

Cell 6

Pico

Cell 6

Pico

Cell 5

Pico

Cell 5

Pico

Cell 4

Pico

Cell 4

Pico

Cell 3

Pico

Cell 3

Macrocell 1

BA list

BCCH SACCH

Microcell 2

BA list

BCCH SACCH

Picocell 3

BA list

BCCH SACCH

Version 1 Rev 0BA Lists Exercise



3–34



4–1

Chapter 4

Microcellular Database

Version 1 Rev 0



4–2

Version 1 Rev 0 Microcellular Database



4–3

Microcellular Database

Objectives

On completion of this chapter the student will have:

� Reviewed the principles of handovers in multilayer systems.

� Discussed the seven Motorola microcellular handover algorithms.

� Discussed the use of adaptive handovers.

� Discussed the add_neighbor command.

� Written an add_neighbor database for a given execise

Version 1 Rev 0Microcellular Handover Criteria



4–4

Microcellular Handover CriteriaWhen planning a microcellular handover strategy, there are some basic criteria thatshould be employed. These criteria detail a strategy for handovers between:

Macro ⇒ MacroThis is the standard power budget or imperative type of handover.

Macro ⇒ MicroWhen the environmental conditions are well known, to ensure that the micro cell is goingto provide a good service to a particular mobile, its level will be measured and when itexceeds a certain value (rxlev_min ) for a given period (delay time), and power budgetconditions are met, this mobile will be allowed to be passed between the macro and themicro.

This period must be long enough to ensure that this mobile is not a fast mobile.

Micro ⇒ MicroLine of sight – Algorithm incorporates a delay timer to limit the handover rate (ping–ponghandovers) and to force fast moving mobiles to hand up to the macro layer before qualityof service is degraded. This is because microcells have a small radius and as the mobiletravels towards the edge of the cell it will suffer interference, also the number ofhandovers generated would cause and unacceptable loading on the system processors.

Around the corner – In this configuration, the signal level is monitored and handoverswill be prevented to the neighbour microcell unless the server level goes below athreshold. This is extremely useful when the topology of the streets can create problemssuch as rapid drop in signal level when turning a corner.

Micro ⇒ MacroIt is necessary to keep the call as long as possible in the micro layer, this effectivelydisables the use of power budget considerations to trigger the handover to the macrolayers. However power budget is still calculated for candidate ordering purposes forimperative handovers such as Rxqual and Rxlev.

System behaviour is dependant on mobile speed. If the speed is low enough themicrocellular system will take the call, but if the speed increases the call will be handedup to the macrocellular layer. For example a car may stop at traffic lights and be locatedin a micro. When the vehicle starts to move faster, the timer of the serving micro cell willprevent handover to further micro and this mobile will be forced to hand up to a macro.

Another reason to hand calls up to the macrocell is when the microcell capacity isexceeded and directed retry or congestion relief is being used. The macrocell cell couldthen be used to take the congested calls.

The main design target can thus be stated as:

“Keep the mobiles on the microcells except when their speed is high enough todegrade their service quality, in which case they are to be served by themacrocells. If their speed reduces such that they can be adequately served by themicrocells, then hand them back to the microcells”.

Motorola defines a number of handover procedures each tailored to a particular scenario,these procedures can be selected on a per–neighbour basis.

Version 1 Rev 0 Microcellular Handover Criteria



4–5

Microcellular Handover Criteria

sys12_ch05_01

Macro Macro

Delay timePbgt

Fast moving MS

Line of sight (micro ormacro)Round the corner

Slow moving MS

Line of sight (micro ormacro)Round the corner

Imperative handoversMS speed

Congestion Relief

Pbgt or Imperativehandovers

Acceptable rxlev

Combat adj chan int

Micro Micro

Version 1 Rev 0Current Motorola Handover Decision Algorithms



4–6

Current Motorola Handover Decision AlgorithmsThe HDPC in the RSS software constantly monitors measurement reports from themobile during a call. The mobile is capable of monitoring up to 64 neighbours, that can bemade up of a maximum 32 SACCH and 32 BCCH neighbours. During a full SACCHmultiframe a total of 104 or 100 measurements (12 for serving cell measurements if DTXon) can be made. These measurements report on the neighbours receive level and alsodecode the BSIC of the neighbours. The mobile also reports on the serving cells receivelevel, receive quality, timing advance, power level, whether DTX is enabled and which BAlist is in use. Once the measurement reports reach the HDPC then they are subject toaveraging, the level of averaging is set by hreqave and hreqt .

The HDPC then makes decisions on handovers, power level changes and timingadvance changes.

Handover triggers are currently based on the following criteria:

1. Receive Quality (Uplink and downlink)

2. Interference level (Uplink and downlink)

3. Receive Signal Strength (Uplink and downlink)

4. Distance (Timing Advance)

5. Power Budget

A decision has to made by the BSC as to what priority should be given to each of the fivecriteria. They are in fact placed in order of priority, Receive Quality being the mostimportant and Power Budget being the least. Therefore, if there are more handover bidsto a cell than free channels, then the bids with cause Receive Quality shall take highestpriority.

Cells that the MS is being handed over to, can also be placed in priority levels. Thesepriority levels are considered together with the list of candidates and the interferencelevels in the choice of new cell. If there are then two cells, which meet the criteria forhandover, then the cell with the highest priority shall be used. This enables umbrella cellsfor instance to be given a lower priority and therefore only handle calls when no other cellis available.

Channel congestion in the best cell shall cause the choice of the second cell. If no cell isavailable and call queuing is employed then the MS will be placed in the queue until therelevant cell becomes available. MS placed in queue for handover purposes take priorityover new calls.

Version 1 Rev 0 Current Motorola Handover Decision Algorithms



4–7

Current Motorola Handover Decision Algorithm

SYS12_Ch5_03

n1

n3

n2

Rxlev

BSIC

Freq

Rxlev

BSIC

Freq

Rxlev

BSIC

Freq

Rxlev (s)Rxqual (s)

Timing AdvPower Level

DTX usedBA used

nCell(1 to 6)

RxQual (ul)RxQual (dl)

Interference (ul)Interference (dl)

Rxlev (ul)Rxlev (dl)

Timing advPbgt

Power ChangesTiming adv changes

Neighbours evaluatedby:

Criteria 1Criteria 2

To BSC (handover_rec)

Cause Value

Qualified n/bours(ranked1 up to 6)

Version 1 Rev 0hreqave and hreqt



4–8

hreqave and hreqtTo set the bin values of the parameters hreqave and hreqt the following commands areused. Two types of algorithm are available, those being unweighted and weighted (forrxqual only) algorithms.

chg_cell_element <alg_name>,<bin_num><alg_num> cell <cell_desc>hreqave =hreqt =

alg_name

The algorithm name specifies the averaging mechanism to be enabled.

surround_cell neighbour Rxlev

rel_tim_adv timing advance

rxlev_dl_ho downlink handover

rxlev_ul_ho uplink handover

rxlev_dl_pc downlink power control

rxlev_ul_pc uplink power control

rxqual_dl_ho downlink handover

rxqual_ul_ho uplink handover

rxqual_dl_pc downlink power control

rxqual_ul_pc uplink power control

bin_num

Is the bin for data storage, range 0 to 1

alg_num

Is the number for weighting if used. The range is from 0 to 255

cell_id

Is the GSM cell id or cell to be affected by the change

The two parameters points to hreqave and hreqt .

hreqave (0 to 31)

hreqt (0 to 31)

Note:

The product of hreqt and hreqave can, at maximum equal 32, as only 32 averages canbe stored at any moment in time.

Version 1 Rev 0 hreqave and hreqt



4–9

hreqave and hreqt

chg_cell_element

<alg_name>

<cell_id>

<bin_name>

surround_cell

rel_tim_adv

rxlev_dl_ho

rxlev_ul_ho

rxlev_dl_pc

rxlev_ul_pc

rxqual_dl_ho

rxqual_ul_ho

rxqual_dl_pc

rxqual_ul_pc

range 0 to 1

<alg_num>

hreqave (0 to 31)

hreqt (0 to 31)

quality_weighting 0 to 255

Version 1 Rev 0Pointing Averaging Mechanisms to Decision Processes



4–10

Pointing Averaging Mechanisms to Decision ProcessesEach averaging mechanism produces at least one set of averages every SACCHmultiframe, these averages are used by decision processes controlling handover andpower control. The software bin where each set of averages is stored, has to be directedto the decision process utilising them. This pin–pointing is specified in add_cell .

n and p voting

The averages can be further processed, by using a voting mechanism. A number ofaverages are taken (n value), these averages are compared to a threshold (set inadd_cell ). The averages are then compared to a threshold (also set in add_cell ), if anumber of these averages (p value) exceeds the threshold then a decision is made. Thisdecision could be for a handover or power increase or decrease.

Averaging Bin Pointer

chg_cell_element....

n and pnumbers

Threshold Comment

ul_rxlev_av_p

dl_rxlev_av_p

n1/p1

n2/p2

l_rxlev_ul_p

u_rxlev_ul_p

l_rxlev_dl_p

u_rxlev_dl_p

Power increase/decrease uplink due to level

Power increase/decrease downlink due tolevel

ul_rxqual_p

dl_rxqual_p

n3/p3

n4/p4

l_rxqual_ul_p

u_rxqual_ul_p

l_rxqual_dl_p

u_rxqual_dl_p

Power increase/decrease uplink due toquality

Power increase/decrease downlink due toquality

ul_rxlev_av_h

dl_rxlev_av_h

n5/p5

n5/p5

l_rxlev_ul_h

l_rxlev_dl_h

Uplink handover due to rxlev

Downlink handover due to rxlev, theseaverages are also used for the serving part ofthe Pbgt calculation for criteria 2.

ul_rxqual_av_h

dl_rxqual_av_h

n6/p6

n6/p6

l_rxqual_ul_h

l_rxqual_dl_h

Uplink handover due to rxqual

Downlink handover due to rxqualul_rxlev_av_ih

dl_rxlev_av_ih

n7/p7

n7/p7

l_rxlev_ul_ih

l_rxlev_dl_ih

Uplink handover due to interference

Downlink handover due to interference

tim_adv_av_alg n8/p8 ms_max_range Handover due to distancencell_rxlev_av_h_calc –––––––

––––––––––––––––––––––––––

Used to access per cell averaged neighbourmeasurements to be used to calculate validneighbour candidates for handovers (criteria1and 2)

p_bgt_rxlev_av_h –––––––––––

––––––––––––––––––––––

Used to calculate averages for neighbour cellmeasurements to be used for power budgetcalculation, when the calculation is done todetermine if the cell qualifies for powerbudget handover.

Version 1 Rev 0 Pointing Averaging Mechanisms to Decision Processes



4–11

Pointing Averaging Mechanisms to Decision Processes

SYS12_Ch4_04

chg_cell_element rxlev_ul_ho, 0 0 <cell id>

Averaging Mechanism

Decision Mechanism

BIN 0

–47dBm

–110dBm

l_rxlev_ul_h = 30

–80dBm

decision_1_n5 = 4

decision_1_p5 = 2

ho_recognised

CV rxlev ul

<n1.....n6>

decision_1_ul_rxlev_av_h = 0

hreqave = 4

hreqt = 4

Measurementreports/averages

every 480ms fromradio

hreqave = 4hreqt = 1

Version 1 Rev 0use_neighbor_pbgt_hreqave



4–12

use_neighbor_pbgt_hreqaveIn order that the sites unaffected by the microcellular deployment can use their existingPBGT calculation the chg_element use_neighbor_pbgt_hreqave flag can be used.This can be used in the PBGT calculation for the neighbour rxlev_dl

Neighbour cell :

The hreqave used for pbgt handover decision and depends upon the source cellparameter use_neighbor_pbgt_hreqave .

– If use_neighbor_pbgt_hreqave is set to 0, hreqave used is the onedefined in surround_cell (in chg_cell_element ).

– If use_neighbor_pbgt_hreqave is set to 1, hreqave is retrieved from theper_neighbor_hreqave which is defined per neighbour (in add_neighbor ).When the per neighbour hreqave value is used, a value of 1 is always usedfor hreqt and the averages are stored in the microcell_av area .

For pbgt handovers, the decision is made for the source cell with hreqave defined inrxlev_dl_ho , and for the neighbour cell with hreqave either defined in per cellsurround_cell , or the per_neighbor_hreqave if use_neighbor_pbgt_hreqave is set to1.

For pbgt neighbour ordering, the decision is made for the source cell with hreqavedefined in rxlev_dl_ho , and for the neighbour cell with hreqave always defined in the percell surround_cell regardless of use_neighbor_pbgt_hreqave .

Note: For pbgt handovers, the parameter decision_1_p_bgt_rxlev_av_h is used tospecify which bin is used, for rxlev_dl_ho and surround_cell , for the purpose of makinga Better Cell (pbgt) handover decision.

For candidate ordering, the parameter decision_1_ncell_rxlev_av_h_calc is used tospecify which bin is used for surround_cell for the neighbour cell averages and for theserving cell averages the parameter decision_1_dl_rxlev_av_h specifies the bin.

Version 1 Rev 0 use_neighbor_pbgt_hreqave



4–13

use_neighbor_pbgt_hreqave (example 1)

Serving Neighbour

PBGThandoverdetected

use_neighbor_pbgt_hreqave = 0

chg_cell_element rxlev_dl_ho, 0 0 <cell id> (hreqave = 8, hreqt = 1

chg_cell_element surround_cell, 0 0 <cell id> (hreqave = 8, hreqt = 1)

decision_1_p_bgt_rxlev_av_h = 0

Candidate ordering uses the same hreqave as for pbgt handover decisionsdecision_1_ncell_rxlev_av_h_calc = 0

sys12_ch05_06

Version 1 Rev 0use_neighbor_pbgt_hreqave



4–14

Version 1 Rev 0 use_neighbor_pbgt_hreqave



4–15

use_neighbor_pbgt_hreqave (example 2)

Serving

Surround cell hreqave

(Per neighbour)PBGThandoverdetected

Neighbour

chg_cell_element rxlev_dl_ho, 0 0 <cell id> (hreqave = 8, hreqt = 1)

Per neighour hreqave set in add_neighbour by surround cell hreqave

Only one bin, hreqt always = 1 (hreqave = 4)

decision_1_p_bgt_rxlev_av_h = 0

For Pbgt neighbour ordering uses per cell hreqave

decision_1_ncell_rxlev_av_h_calc = 0

use_neighbour_pbgt_hreqave = 1

chg_cell_element surround_cell, 0 0 <cell id> (hreave = 8, hreqt = 1)

For Pbgt handovers uses per neighbour hreqave

Version 1 Rev 0The Seven Motorola Microcellular Handover Procedures



4–16

The Seven Motorola Microcellular Handover ProceduresWhen the microcellular feature is enabled and the need for a power budget handover isdetected, the handover process checks the CM database to see if there are any furtherpower budget restrictions, these are set in the neighbour cells description(pbgt_alg_type ) and have a valid range from 1 to 7. These algorithms are describedbriefly on this page, but in greater detail later. Another important point is candidateordering which is a key component of the algorithms used. Once again these aredescribed later.

Algorithm Title pbgt_alg_type

Conventional GSM PBGT 1

Restricted PBGT for macrocells

2

PBGT with RXLEV as qualifier 3

PBGT with time in cell asqualifier

4

PBGT with delay sinceneighbour level exceedsthreshold as qualifier

5

Delayed power budget usingdynamic handover margin

6

PBGT algorithm to avoidadjacent channel interference

7

Version 1 Rev 0 The Seven Motorola Microcellular Handover Procedures



4–17

The Seven Motorola Microcellular Handover Procedures

� Specified on a per neighbour basis by pbgt_alg_type

� Each neighbour cell is classified by an algorithmranging from 1 to 7

Version 1 Rev 0Type 1 Algorithm



4–18

Type 1 Algorithm

PBGT algorithm

Algorithm 1 is simply the standard GSM power budget algorithm. The difference from theprevious implementation is that the averaging period (hreqave ) can be set on aper–neighbour basis,

The power budget formula can be considered in two parts, the left handside the servingcell and the right handside the neighbour cell. The power budget calculation is carriedout every 480ms (SACCH multiframe). For each reported neighbour of all mobilesengaged in traffic the aim of the formula is to afford the mobile the lowest uplink pathloss(not subject to N & P voting).

SYS12_Ch4_08

PBGT(n)=

For handover to take place it is usual for: PBGT(n)>ho_margin

– (min(ms_txpwr_max,P) – rxlev_dl)

NEIGHBOUR

(min(ms_txpwr_max,P) – rxlev_dl – PWR_C_D)

SERVER

Version 1 Rev 0 Type 1 Algorithm



4–19

Type 1 – Power Budget Assessment

SYS12_Ch4_09

Min(ms_txpwr_max,P) – rxlev_dl – PWR_C_D Min(ms_txpwr_max,P) – rxlev_dl

PBGT(n) = [Min(ms_txpwr_max,P) – rxlev_dl – PWR_C_D] – [Min(ms_txpwr_max,P) – rxlev_dl]

PBGT(n) > ho_margin

Serving neighbour

All values in dBm




4–20

Downlink RXLEV only

Probably the most important factor in any handover decision and selection processshould be the mobiles perception of its serving downlink level as compared to neighboursdownlink level. This is accounted for in the power budget expression:

SYS12_Ch4_09a

PBGT(n)=

NEIGHBOUR

( – Rxlev_DL ) –

SERVER

( – Rxlev_DL)

As can be noted, all the other inputs to the formula have been removed and this levelcomparison can be easily seen. PBGT(n) will become a value greater than 0 if thereported neighbour level becomes greater than the server.

The rxlev_dl averages for the neighbour can come from two sources. This is coveredlater in the course.




4–21

Considering RXLEV Only

SYS12_Ch4_10

Serving

43dBmNeighbour

43dBm

PBGT(n) > 0

PBGT(n) = [ –rxlev_dl ] – [ –rxlev_dl]

<server> <neighbour>

Version 1 Rev 0Adapted Power Consideration



4–22

Adapted Power ConsiderationA direct level comparison is not always correct because the mobile is potentially reportingadapted power on the serving cell where as, the neighbour is being measured at its fullBCCH power level. A correction factor must therefore be considered:

SYS12_Ch4_11

PBGT(n)=

NEIGHBOUR

( – Rxlev_DL – PWR_C_D ) –

SERVER

( – Rxlev_DL)

Where PWR_C_D = max_tx_bts – Actual BTS output power.

PWR_C_D will always equal a positive value, or zero. In the example shown opposite thedownlink serving receive level is –80dBm and the downlink neighbour receive level is–72dBm. At first glance it appears that the neighbour cell has the better level. However,this does not take into account the transmit level of the BTSs. The server has a transmitpower of 35dBm and the neighbour has a transmit power of 43dBm. But is the server onfull power? Well in this case no, as the maximum transmit power that the server canoutput is 43dBm. So by applying the correction faction the system can take adaptedpower into consideration and compare like for like. Therefore the power budget calculatesto 0, the same case as before. If the mobile moved towards the neighbour, its receivelevel would increase and the servers receive level would decrease and hence the powerbudget of the neighbour would become more positive and hence a likely candidate forhandover.

Version 1 Rev 0 Adapted Power Consideration



4–23

Adapted Power Correction Factor

sys12_ch05_12


= 0

Serving

35dBm

max_ tx _bts = 0(43dBm)

Neighbour

43dBm

PBGT(n) > 0

– 72 dBm– 80 dBm

PBGT(n) = [ –rxlev_dl – PWR_C_D] – [ –rxlev_dl]

Where PWR_C_D = max_tx_bts – Actual BTS output power

= [80 – (43 – 35)] –[72]

Version 1 Rev 0Uplink Consideration



4–24

Uplink ConsiderationRemember that the aim of this formula is to provide the mobile with the lowest uplinkpathloss, so far the uplink path has not been considered. The first part of each side ofthe formula provides this comparison.

min (ms_txpwr_max, P)

ms_txpwr_max of the neighbour can be specified in add_neighbor for an external celland for an internal neighbor the ms_txpwr_max is read from the neighbour cell area ofthe database (add_cell ). The value of ‘P’ equates to the maximum power of the mobileconcerned.

The power budget formula is designed for a mobile suited to the PLMN being used, thatis that the mobile always has sufficient power to support all cells within the PLMN. In thiscase the P value is never used and the ms_txpwr_max is always the deciding uplinkfactor. The following examples illustrate this ideal.

Note:

ms_txpwr_max of the server equates to the value specified in max_tx_ms in add_cell .

In the next three examples we have two equally sized cells, large server – smallneighbour, and small server – large neighbour. For each, example values of relevantdatabase settings have been shown. Please bear in mind that every situation hasdifferent needs and these are only examples designed to show the principle and not to betaken as defaults.

Example One – Equally Sized Cells

When the cells are of equal size the values of max_tx_ms (server) equalsms_txpwr_max (neighbour). This gives neither cell advantage when calculating powerbudget. Therefore for the mobile would have to move towards the neighbour for its powerbudget to increase and hence overcome the handover margin for a handover to takeplace.

Version 1 Rev 0 Uplink Consideration



4–25

Example One – Equally Sized Cells

SYS12_ch05_13

Serving35dBm

Neighbour43dBm

<server>

<neighbour>

= 0

PBGT(n) > 0

Power Class = 4

PBGT(n) = [Min(ms_txpwr_max,P) –rxlev_dl – PWR_C_D]

–[Min(ms_txpwr_max,P) –rxlev_dl]

=[33+80 –(43 – 35)] –[33+72]

ms_txpwr_max = 33max_tx_bts =0max_tx_ms = 33

– 80dBm–72dBm

Version 1 Rev 0Example Two – Large server, Small Neighbour



4–26

Example Two – Large server, Small NeighbourIn this case the value of ms_txpwr_max (neighbour) is a less than max_tx_ms (server)by a margin of 6 dBm. With the same receive levels as before the neighbours powerbudget has a value of 6 dB, hence making it more attractive for handover. This can takeplace because the actual size of the neighbour cell is smaller than the server, so theactual distance travelled on the uplink is less so the mobile power required in that cell canbe less than the server.

Version 1 Rev 0 Example Two – Large server, Small Neighbour



4–27

Example Two – Large server, Small Neighbour

sys12_ch05_14

Serving35dBm

Neighbour37dBm

<server>

<neighbour>

PBGT(n) > 0

Power Class = 4

PBGT(n) = [Min(ms_txpwr_max,P) – rxlev_dl –PWR_C_D]

– [Min(ms_txpwr_max,P) –rxlev_dl]

= [33 + 80 – (43 – 35)] – [27 +72]

= 6dB

max_tx_bts =0max_tx_ms =33

– 80dBm

–72dBm

ms_txpwr_max =27

Version 1 Rev 0Example Two – Large server, Small Neighbour



4–28

Example Three – Small Server, Large NeighbourIn this case the value of max_tx_ms is less than ms_txpwr_max by 6 dBm. If thereceive levels are the same as in the previous examples, then the power budget of theneighbour is 0 dBm. This has the effect of the smaller cell retaining the mobile for as longas possible and the receive level of the larger neighbour will have to exceed the server by0 dBm plus the handover margin.

Version 1 Rev 0 Example Two – Large server, Small Neighbour



4–29

Example Three – Small Server, Large Neighbour

sys12_ch05_14a

Server35dBm

Neighbour43dBm

<server>

<neighbour>

PBGT(n) > 0

Power Class = 4

PBGT(n) = [Min(ms_txpwr_max,P) –rxlev_dl – PWR_C_D]

– [Min(ms_txpwr_max,P) –rxlev_dl]

= [27 + 80 – (37 – 35)] – [33 + 72]

= 0dB

max_tx_bts = 0max_tx_ms = 27

ms_txpwr_max = 33

–80dBm–72dBm

Version 1 Rev 0Type 1



4–30

Type 1

Power budget exercise part 1

The figures specified on the facing page can be used by the HDPC to calculate thePower budget assessment. Use the working area to calculate PBBT (n).

SERVING (macro)

serving= min (ms_txpwr_max,P) – rxlev_dl – PWR_C_D

serving= – –

serving=

NEIGHBOUR (micro)

neighbour= min (ms_txpwr_max(n),P) – rxlev_ncell (n)

neighbour= –

neighbour=

PBGT (n) = Serving – Neighbour

PBGT (n) =

PBGT (n) =

Power budget exercise part 2

If the measured parameters remain the same and the neighbor was a microcell whatwould you change if you wished the PBGT(n) figure to equal at least 8. Note: the uplinkof the microcell does not require 33 dBm. It would only require 25 dBm.

Parameter ......................... could be altered to equal ......................

Version 1 Rev 0 Type 1



4–31

Type 1– Power Budget Example� SERVING CELL DATABASE PARAMETERS

Cell identity= 234 10 255 038

max_tx_ms= 33 dBm

max_tx_bts= 0 (43dB)

ms_txpwr_max_def = 33dBm

add_neighbour external 234 10 256 039

ms_txpwr_max_cell= 33dBm

� BEST NEIGHBOURS DATABASE PARAMETERS

Cell identity= 234 10 256 039

ms_txpwr_max_def= 33

ms_txpwr_max_cell= 33

� RXLEV AVERAGE

SERVING (Reported)= –90dBm

NEIGHBOUR= –75 dBm

� SERVING CELL DL OUTPUT POWER= 31dBm

� MOBILE= CLASS 4

CLASS MAX POWER dBm� ��

� � �

� ��

� ��

� ��

Version 1 Rev 0Criteria 1



4–32

Criteria 1Criteria 1 ensures that the mobile is perceiving each neighbours Rxlev at a power levelgood enough for the downlink path to support a ‘good call’, criteria 1 is as follows:

rxlev_ncell > rxlev_min(n) + Max (0, Pa)

rxlev_ncell is the latest averaged average processed for that neighbour. rxlev_min (n)is the database parameter set in the add_neighbor command. For internal cellsrxlev_min_cell is optional and if not specified then rxlev_min_def in the add_cellcommand of the server is used.

The last part of this calculation tempers the perceived downlink rxlev average with thepotential uplink path.

Max (0, Pa) where Pa = ms_txpwr_max(n) – P

P = max power of ms

If the MS is suited for the PLMN in question Pa will always equal either zero or a negativevalue and will therefore not be considered.

The value of ms_txpwr_max (n), can be set by ms_txpwr_max_def in add_cell forundefined adjacent cells and ms_txpwr_max_cell in add_neighbor .

If the MS is not suited to that neighbour, ie its maximum power can not support thatrequired by that cell then the averaged rxlev_ncell would have to become a greatervalue to overcome this handicap. Criteria 1 would therefore prevent such a handoveruntil the MS was deeper into that neighbour.

Any neighbour failing Criteria 1 is not further considered in any handover decisionprocess.

The software bin and hence averages used for criteria 1 are created in the averagingmechanism “chg_cell_element surround cell ” for per cell averaging or fromadd_neighbor per neighbour surround_cell hreqave which in both cases is pointed toby “decision_1_ncell_av_h_calc ” in “add_cell ”.

In the example shown opposite the neighbour receive level minimum has been set to–80dBm and the actual receive level is –70dBm. Even after the mobile power has beentaken into consideration criteria 1 allows the neighbour to be taken into consideration forfurther processing by criteria 2.

Version 1 Rev 0 Criteria 1



4–33

First Criteria

sys12_ch05_17

ServingNeighbour

MS PowerClass 4 (P)

– 70 > – 80 + 6

– 70 > – 74

Pa = ms_txpwr_max – P

6 = 39 – 33

rxlev_min_cell = 30ms_txpwr_max = 39

– 80dBm

–70dBm

rxlev_ncell > rxlev_min(n) + max (0,Pa)

Version 1 Rev 0Criteria 2



4–34

Criteria 2Each neighbour, for that mobile, that satisfies criteria 1 is then subjected to criteria 2.criteria 2 specifies that:

PBGT(n) – ho_margin

ho_margin for both external and internal cells can be specified in the add_neighborcommand. For internal cells this parameter is optional and if not specified then theho_margin_def in the add_cell of the neighbour is used.

Criteria 2 will produce a result for each neighbour, which has got to be greater than zerofor consideration by the specific handover procedure to follow.

For microcellular the neighbours are then ranked by algorithm type.

The neighbour software bin and hence the averages used in criteria 2 are set inchg_cell_element surround_cell which is pointed to bydecision_1_ncell_rxlev_av_h_calc in add_cell .

The server averages used in criteria 2 are again set in chg_cell_element rxlev_dl_howhich in this case is pointed to by decision_1_p_bgt_rxlev_av_h in add_cell .

In the example shown the power budget calculates to 2dB. The ho_margin is set to 6dB,once criteria 2 is applied, it gives a value of – 4dB.

Version 1 Rev 0 Criteria 2



4–35

Second Criteria

sys12_ch05_18

Serving

35dBm Neighbour43dBm

MS PowerClass 4 (P)


PBGT(n) = [Min(ms_txpwr_max,P) –rxlev_dl – PWR_C_D] – [Min(ms_txpwr_max,P) – rxlev_dl]

2 = [33 + 80 – (43 – 35)] – [33 + 70]

Criteria 2 specifies PBGT(n) – ho_margin 2 – 6 = – 4dB

rxlev_min_cell = 30ms_txpwr_max = 33max_tx_bts = 0max_tx_ms = 33

ho_margin = 6ms_txpwr_max = 33

– 80dBm– 70dBm




4–36

Type 1 Algorithm

Uses

This is an extension of an existing algorithm to a per neighbour basis. As this is the case,it will still mainly be used in its traditional role, that of macro to macro handovers.




4–37

Type 1 Algorithm

sys12_ch05_19

Uses

Preferred handover mechanism for macro to macro handovers

Trigger mechanism is PBGT

Macrocell (Type 1) Macrocell (Type 1)

Serving cell is a macrocell

Ordering for microcell algorithm




4–38

Type 2 AlgorithmIf a neighbour is defined as a type 2 in the database, that means that a handover to thatcell will only be triggered imperative causes. Normally used to defined macro neighboursin microcells.

This algorithm type is used for Macrocells neighbours and any other neighbours to whichpower budget handovers are not allowed. The element pbgt_ho_needed shall always beset to FALSE for neighbours of this type.




4–39

Type 2 Algorithm

sys12_ch05_20

MicrocellMicrocell

To retain traffic in a microcellular layer, the marcocell is made atype 2 neighbour.

Additionally if an type 3 (round the corner neighbour)generates a handover cause and the handover fails then a type2 neighbour will be next in the candidate list

If an imperative handover takes place (rxlev/rxqual), type 2neighbour gets priority.

Macrocell (type 2 neighbour)

HO fails MS hands up to macrocell

This algorithm type is used for macrocells neighbours and anyother neighbours to which power budget handovers are not allowed.




4–40

Type 3 AlgorithmThe operator has the option to select a power budget algorithm where once the standardGSM power budget conditions have been met, an additional restriction must be overcomebefore a power budget handover will be initiated to that neighbour cell. The additionalrestriction being that of the serving cell uplink and downlink RXLEVs must be belowspecified thresholds. These thresholds are defined on a per neighbour basis. Thisalgorithm prevents power budget handovers to neighbours located around a corner untilthe receive levels of the serving cell has dropped below the thresholds, indicating that theMS has moved around the corner.

This guards against the case where the threshold is crossed only due to a temporaryfade. The probability of this happening both in the uplink and downlink is low due to the45Mhz frequency separation.

Signal losses of as much as 20–30 dBs in the space of 10–40 metres can be measuredwhen turning a street corner. With this in mind, it is imperative that the handoveralgorithm reacts quickly enough to maintain the call.

In the diagram opposite, a mobile is using Micro 1. When it reaches the area A, the signallevel of Micro 2 will be higher but if the mobile does not turn the corner it is not necessaryto hand–over to Micro 2 as this cell would experience a high drop in rxlev around thecorner 4. This scenario could lead to drop calls when the speed of the mobiles is high.Using the type–3 algorithm with this configuration will avoid the potential problems bymaintaining the call on micro 1.

Another feature implemented in this configuration is an alternative ordering in thehandover candidate list. When a handover is generated for an around–the–corner type–3neighbour but the microcell is blocked as the corner is turned, all macro neighbours willbe considered as candidates, ordered by PBGT. This will avoid problems in the scenariowhere the mobile turns the corner, as the server signal level is expected to drop abruptlyand a handover to the macro layer is triggered.

An other application for this algorithm would be where there is a serving microcell and anin building microcell.

GSR5 Enhancements

An optimised type 3 pbgt handover algorithm has been introduced since GSR 5. Thismakes use of relative thresholds (path loss) instead of absolute level thresholds. Thistakes into account that the BTS maybe using adaptive power control and preventshandovers occurring at different points for different carriers.

For a handover to take place

[Pbgt(n) > ho_margin] and [dl path loss > dl threshold] and [ul path loss > ul threshold]

Generate handover cause

Note: ul path loss = ul transmit pwr – ul rxlev

dl path loss = dl transmit pwr – dl rxlev




4–41

Type 3 Algorithm

sys12_ch05_21

sys12_ch05_21

When mobile passesthrough A, it wouldbe undesirable tohand over to Cell 2

A Cell 1

Cell 2

900 Cell – type 3neighbour

1800 Cell – serving

PBGT (n) criteria met for 900 cell

Rxlev on 1800 server has to fall below preset level

ul_rxlev_serv_l and dl_rxlev_serv_l (add_neighbour)

If the mobile follows thisdirection, Cell 2 would notonly have to meet powerbudget requirements, butthe rxlev both on the uland dl would have to fallbelow a preset level onthe server.

If microcell isblocked after thecorner is turned,

all macrocellsare considered

as neighbours bypower budget.

ul_rxlev_serv_l

dl_rxlev_serv_l




4–42

Type 4 AlgorithmThis configuration is typically (but not exclusively) used between micro neighbours thatare near LOS related. The algorithm incorporates a delay timer to limit the handover rateand to force fast moving mobiles to hand up to the macro layer before quality of service isdegraded. This configuration is identified as type 4 in the database definition.

System behaviour is dependent upon mobile speed. If the speed is low enough themicrocellular system will take the call, but if the speed increases the call will be handedup to the macrocellular layer. The algorithm contains the additional restriction that the MSmust have been on the current channel for at least the number of SACCH periods definedby the per neighbour parameter qualify_time . This value is compared to a counterqualify_count , which is initially set to zero when the MS enters that cell and incrementedevery time a measurement report is received for that channel until the value reaches amaximum value of 255. If the mobile qualifies for the standard power budget handover,the quality_count is compared to the qualify_time. If the qualify_count is greater thanqualify_time , then that neighbour is set to true for a power budget handover.

qualify_time 0 to 255 SACCH multiframes

In the example opposite, a mobile located in a car handed into the microcellular system(Microcell 1) when it was stopped at a traffic light: the system considered it was a slowmoving mobile. If the vehicle speed subsequently increases such that the mobile isconsidered fast moving by the system, the timer of the serving microcell will prevent thehandover to Microcell 2 and this mobile will be forced to hand up to the macro layerthrough an imperative handover.

Note: The timer can be set to zero and then can be used as the standard power budgethandover mechanism between microcells due to candidate ordering.




4–43

Type 4 Algorithm

Mobile handed up to Macro

layer because it has not

been in the cell long enough

for power budget reasons

qualify_time = 100

Approx time 50s

Mobile handed over to

microcell 2 as it meets

power budget requirements

and qualifies for time

because it has been

stationary at the traffic lights

for more than 50s

Mobile handed over to

microcell 2 as it meets

power budget requirements

and qualifies for time

because it has been

stationary at the traffic lights

for more than 50 s

to handover to mircrocell 3

Time spent in microcell 2 = 10s

Microcell 3 Microcell 2 Microcell

sys12_ch05_22

qualify_time = 0

time = 0s

Candidate ordering places type 4 neighbours at the top of list

A Pbgt handover is triggered from microcell 1 by type 4 neighbour

Time is not a factor for microcell 2 as qualify_time = 0

Microcell 3 = type 4 Microcell 2 = type 4 Microcell 1 = type 4




4–44

Type 5 AlgorithmIn this case the trend of the neighbour signal level is monitored. To allow a handover to aneighbour defined to use this configuration, its level has to exceed a threshold for adefined period of time. This configuration may be used to hand down from the macro tothe micro layer when a microcell neighbour is deemed to have a high signal levelcontinuously for a period of time. The period and threshold may be configured to controlthe handover rate between layers and to identify the mobiles whose speed is over thedesired limit and therefore should remain in the macro layer.

Algorithm Description

The rxlev threshold (rxlev_ncell_h ) is set in add_neighbor as is the qualify_delay timerwhich is set in SACCH multiframes. This delay is stored in the elementqualify_delay_count and is initialised to the value set in qualify_delay. Once the callqualifies for the standard GSM power budget algorithm and the neighbour exceeds therxlev threshold, the qualify_delay_count is decremented. If the neighbour goes belowthe rxlev threshold the qualify_delay_count is reset to the qualify_delay value. Thepower budget need is only set to true once the qualify_delay_count reaches 0.

qualify_delay 0 to 255 SACCH multiframes

rxlev_ncell_h 0 to 63

In the example opposite, a fast moving mobile is identified by the serving macrocell andis never handed down to the micro layer. It did not report the microcell signal level asexceeding the required threshold for long enough.




4–45

Type 5 Algorithm

sys12_ch05_24

Macro

Time in secs = 10

MS qualifies forPbgt handover

Microcell C

Rxlev = –70dBm

qualify_delay = 30 (approx 15s)

rxlev_ncell_h = 40 (–70dBm)

Version 1 Rev 0Optimisation of type 5 handovers



4–46

Optimisation of type 5 handoversType 5 handovers are intended for hand–down calls from macrocells to microcells. Aproblem occurs though with the indoor environment. This is because good quality mightexist with relatively low RXLEV. As hand–downs are based on relatively high threshold(based on outdoor situation) a hand–down to macrocell to microcell might not take place,even when the microcell is the correct cell for the call to be in. To avoid this problem,optimisation of this procedure causes type 5 handover algorithm to ignore the levelthreshold when the power budget between the serving cell and the neighbour cell meetsa settable handover margin.

ho_margin_type5 –63 to 63

def = 63

(set in modify_neighbor )

If rxlev(n) > rxlev_ncell_h or pbgt(n) > ho_margin_type5(n)

Then decrement qualify_delay_count

or else reset qualify_delay_count

if rxlev(n ) < rxlev_ncell_h or pbgt(n) < ho_margin_type5 (n)

If qualify_delay_count = 0 and pbgt(n) > ho_margin_type5 (test only)

Then handover maybe generated if

pbgt(n) – ho_margin_cell > 0

Version 1 Rev 0 Optimisation of type 5 handovers



4–47

Optimisation of type 5 handovers

Serving Cell (Macro)

Neighbour Cell (Pico)

ho_margin_type5 = –10

or

Decrement qualify_delay_count (10 SACCH)

rxlev (n) > rxlev_ncell_h pbgt (n) > ho_margin_type5 (n)

– 81> – 80 No –6 > –10 Yes

rxlev_ncell_h = 30

qualify_delay = 10

– 75dBm

– 81dBm

Pbgt (n) = –6dB

ho_margin(n) = –8

Genrate handover if pbgt(n) – ho_margin(n) > 0 –6 – (–8) = 2 Better Cell handover triggered

Version 1 Rev 0Type 6 Algorithm (Delay PBGT using Dynamic ho_margin)



4–48

Type 6 Algorithm (Delay PBGT using Dynamic ho_margin)This configuration is designed to penalise the handover margin for a defined period oftime. When the PBGT calculation exceeds the ho_margin , the penalty will be appliedand when a timer expires a different value will be subtracted from the ho_margin .Effectively it attempts to limit the handover rate and may be used to hand down to themicrocellular layer as fast mobiles may be identified via this mechanism as well. It mayalso be used between microcells to force the fast mobiles to hand up to the macro layer.

In addition, the algorithm has the flexibility to allow the handovers during the penalty timein the scenario where rxlevs of the cells change very fast and the PBGT calculationexceeds the dynamic ho_margin requirements.

The algorithm makes use of a dynamic handover margin. It also makes use of threedatabase parameters set in add_neighbor .

ho_static_offset 0 to 127

ho_dynamic_offset 0 to 127

delay_time 0 to 255

Description of variables

ho_margin(n) Per neighbour handover margin.

ho_margin _dyn Local variable used within this procedure only

qualify_delay_count(n) Value stored per neighbour in the active data block

Algorithm Definition

Initially if the pbgt(n) is greater than ho_margin(n) , then the count ofqualify_delay_count is set to delay_time . For each measurement report received, thePBGT(n) is checked and criteria 1 and 2 calculated.

If:

qualify_delay_count(n) > 0

then

qualify_delay_count(n) = qualify_delay_count(n) – 1 (SACCH Multiframes)

and

ho_margin_dyn = ho_margin(n) + ho_static_offset

If qualify_delay_count(n) = 0 then

ho_margin_dyn = ho_margin(n) + ho_static_offset(n) – ho_dynamic_offset(n)

If pbgt(n) > 0 and pbgt(n) > ho_margin_dyn

Then a power budget handover reason is set to true for this neighbour.

Version 1 Rev 0 Type 6 Algorithm (Delay PBGT using Dynamic ho_margin)



4–49

Type 6 Algorithm

Diagram number

ServCell

Timer expires

PBGT(n) > ho_margin......Timer startsho_margin_dyn = ho_margin(n) + ho_static_offset(n)

ho_margin_dyn = ho_margin(n)+ho_static_offset – ho_dynamic_offsetIf PBGT(n) > 0 and PBGT(n) > ho_margin_dyn PBGT handover need

N/bourCell

ho_static_offset = 4

ho_dynamic_offset = 2

delay_time = 60 (30s)

Time taken 30s

PBGT(n)(10dBm) > ho_margin_dyn

(2 + 4 – 2 = 4)

Yes – so the indoor cellset to true for thisneighbour

PBGT(n)(4dBm)>ho_margin(2dBm)

Count = 60 SACCH

ho_margin_dyn = 2+4 = 6

Too much for PBGT to indoor cell

PBGT(n)(0dB)>ho_margin_dyn

(2 + 4 – 2) = 4

No so the indoor cell is set false as a neighbour

Version 1 Rev 0Handover Scenario for Adjacent Channels (Both BCCH Carriers)



4–50

Handover Scenario for Adjacent Channels (Both BCCH Carriers)

Ideally there should be separation between the micro and macro layer frequency bands.If the frequency spectrum is limited in a particular network it may be necessary to assignadjacent channel frequencies.

The GSM recommendations indicate that degradations occur at an adjacent channelinterference level of about –9dB in a fading channel (no shadowing). This means that fora mobile moving from one microcell to another, where the channels assigned areadjacent (see diagram), there is a limited window in which handover can occur.

Only as the neighbour cell’s signal gets within 9dB of the serving channel does theneighbour BSIC become decode–able. The MS can then start reporting this neighbourchannel and the BSS can start the averaging process. If the handover command is notsent before the target channel exceeds the serving channel by 9dB, the handover mayfail because the handover command becomes corrupted.

The other constraint on the handover is that the handover process itself will only startwhen the power budget expression exceeds the ho_margin .

The handover success rate is largely dependent on mobile speed and adjacent channelhandover parameters.

To minimise problems the following recommendations should be adopted;

� Use as large a frequency set as possible in the microcell layer. As far as possibleavoid the use of adjacent channels in adjacent cells.

� Wherever possible, avoid the use of adjacent channels in neighbour cells whichare “round the corner” from each other. The rapid signal changes in a “round thecorner” scenario make the window in the diagram smaller in terms of distancetravelled.

� Avoid the use of adjacent channels in neighbour cells which may encounter fastmoving mobiles.

� Use short averaging periods and low ho_margins for adjacent channel handovers.

� In cases where micro/macrocell frequencies are separated only by a narrow guardband, (one channel), the microcell frequency which is nearest to the macrocellfrequency, should be assigned to the microcells furthest away (in distance) fromthe macrocell.

� If none of the above recommendations can be adopted then use of the 7thalgorithm type may be utilised.

Version 1 Rev 0 Handover Scenario for Adjacent Channels (Both BCCH Carriers)



4–51

Handover Scenario for Adjacent Channels (Both BCCHCarriers)

sys12_ch_03_09

Power

Distance

9dB 9dB

AdjacentBSIC isdecode – ablehere

TargetPBGTbeatsho_margin

ho_commandbecomesunreliable

Serving

Neighbour

Large micro frequency set

Avoid adj channel frequencies for round the corner neighbours

Avoid the use of adj channels which are likely to encounter fast handovers

Use short averaging periods and low ho_margins for adj channel

Distance adj channel micros from macro

Alternatively use the type 7 handover algorithm

�

�

�

�

�

�




4–52

Type 7 AlgorithmIn large microcellular deployments where frequency spectrum for micros is limited, thereare situations where it is impossible to avoid deploying adjacent microcells with adjacentBCCH frequencies. As a mobile being served by one of these cells approaches theinterfering neighbour cell, the quality of the call degrades perhaps to the point of droppingaltogether. Assuming that both cells have only a single carrier, neither an intra–cellhandover nor a handover to the interfering neighbour improves the situation.

This algorithm allows a third Cell, which is not on an adjacent channel, to be the preferredtarget for handover even though an interfering neighbour may have the strongest signal.When Power budget – adj_chan_ho_margin > 0

a handover will be generated before the neighbour signal strength (and thus interference)becomes too strong to drop the call.

Algorithm Definition

During the handover detection phase the type 7 algorithm computes the power budgetequation using rxlev averages from the bin dl_rxlev_av_h_dec for the serving cell andncell_rxlev_av_h_calc for type 7 neighbour cells and evaluates the equation

Power budget – adj_chan_ho_margin > 0

If any of the type 7 neighbours pass the above equation, a handover cause ofADJ_CHAN_INTF is detected, this is an imperative handover even through the powerbudget equation is used to detect the handover. The relative priority of this handover isjust above that of the power budget handover. The handover is performed to a celldifferent from this neighbour. This is managed because we delete the neighbour thatactivated this condition from the candidate list as it will be explained in the candidate listgeneration section.

Any neighbours that satisfy criteria 1 will be a candidate for handover. If no neighbourssatisfy criteria 1 then no handover will be generated.

A database parameter is included to detect the risk coming from neighbours in adjacentfrequencies, when defined as type 7, this is adj_chan_ho_margin .

adj_chan_ho_margin– 63 to 63 (set in add_neighbor )




4–53

Type 7 Algorithm

sys12_ch05_26

ARFCN 10 ARFCN 11

ARFCN 21

Cell A Cell B

Cell C

Serving cell

Type 7

Cell B satisfies criteria for PBGT handover but fails additional

Cell C passes criteria 1 so handover generated to it

pbgt – adj_chan_ho_margin > 0 (for cell B)

constraint of adj_chan_ho_margin




4–54




4–55

Type 7 Algorithm Example

sys12_ch05_27

ARFCN = 10

Micro (Serving)

ARFCN = 11

Micro

Macro

ARFCN = 21

Handover to Macro

Handover toMicro when pbgtallows – use adj

adj_chan_ho_margin = 9

pbgt(n) Micro = 10

pbgt(n) – pbgt_adj_chan_ho_margin > 0

10 – 9 > 0 PBGT handover changed to imperative

Use long hreqave so changes take longertime to alter outcome

ho_margin(n) = 6

channel int test

Version 1 Rev 0Interference Avoidance Test



4–56

Interference Avoidance TestAnother problematic situation could appear when calls are handed over to a cell that hasa neighbour with adjacent (BCCH) frequency. It is possible to enable the BSS to performan interference avoidance test on the neighbour candidate before handing it over a call.This test can be done regardless of which of the seven types is used for this neighbour.

If adj_chan_intf_test enabled in NEIG1and any other valid neighbour NEIG2 (of thecurrent cell) has an adjacent channel frequency with the candidate neighbour (NEIG1)then perform following check:

Candidate neighbour rxlev – rxlev of neighbour on adj chan < adj_chan_rxlev_diff

If check fails then delete neighbour N1 from candidate list.

adj_chan_intf_test0 = no 1 = yes

adj_chan_rxlev_diff – 63 to 63 (both set in add_neighbor )

Example

A mobile is on a serving cell and detects a neighbour with an adjacent channel frequency,the candidate neighbour rxlev is –70dBm and the adjacent channel neighbour rxlev is–75dBm.

adj_chan_rxlev_diff = 9dB

So

Candidate neighbour rxlev – rxlev of neighbour on adj chan < adj_chan_rxlev_diff

–70 –(–75) < 9

5 < 9

The check has failed as the rxlev difference between the two neighbours is only 5dBwhich would cause a interference problem to the MS.

Version 1 Rev 0 Interference Avoidance Test



4–57

Adjacent Channel Interference Avoidance Test

sys12_ch05_28

ARFCN 20 ARFCN 10

ARFCN 11

Cell A Cell B

Cell C

Serving cell

For Cell B and Cell C

Cell B and Cell C is a valid neighbour of the serving cell A

Cell B rxlev – Cell C rxlev < adj_chan_rxlev_diff

If test fails remove candidate neighbour from candidate list

adj_chan_intf_test = 1

Version 1 Rev 0Setting of Candidate List



4–58

Setting of Candidate ListUsing the microcell implementation, each neighbour is assigned a power budgetalgorithm to be used for that neighbour. Upon receipt of each measurement report theBSS uses the assigned algorithm for each neighbour reported by the MS to determine ifthe MS qualifies for a power budget handover to that neighbour. The BSS then evaluatesthe number of neighbours that qualify for a power budget handover. These neighboursare then prioritised based on the algorithm used to determine the power budget handoverqualification and the value of the power budget calculation.

The BSS will then manipulate the list of candidate cells based on the flow chart opposite.

Further to this process there are a number of alternative functions that are defined incourse SYS03 Database Applications. Specifically these are:

worse_neighbor_ho Allows handovers to a neighbour with a lower rxlev than the currentserving cell.

ho_only_max_power For uplink handovers, the MS must be at full power. For downlinkhandovers, the base must be at full power to take place.

neighbor_journal =1 No warm up period for neighbours, all neighbour informationpadded with zeros. Averaging and power budget calculation will begin immediately.If apreviously reported neighbour is missing in the measurement, a zero rxlev is used for theneighbour. Stored neighbour information will be removed when the disuse count is equalto the surrounding cell hreqave (set in add_neighbor ) or 8 depending on the setting ofdisuse_cnt_hreqave.

neighbor_journal = 0 There is a warmup period for the surround cell hreqave beforepower budget calculations begin. The last received rxlev for the unreported neighbour willbe used for missing data. Stored neighbour information will be removed when the disusecount is equal to the surrounding cell hreqave (set in add_neighbor ) or 8 depending onthe setting of disuse_cnt_hreqave.

disuse_cnt_hreqave 0 Use max count which equals 8

1 Use surround cell hreqave (set in add_neighbor )

In case of a mobile missing reports, attention should be paid to the parametermissing_rpt in the add_cell:

If missing_rpt = 0

The last measurement value is repeated and the averaging, voting and handoverdecisions will still be done. One limiting factor in time to go on repeating measurements islink_fail , when this counter expires then the link will be broken down under control ofT3109.

If missing_rpt = 1

No averaging or handover will happen and this measurement report will be forgotten. Nodl handover or power control decisions will be made. The uplink ones will continue asnormal.

Version 1 Rev 0 Setting of Candidate List



4–59

Setting of Candidate List

SYS12_Ch4_29

Remove any neighbours that failthe interference avoidance test

Remove any neighbour that does not satisfyadditional requirements of its algorithm (NA type 1 and 2)

Evaluate Criteria 1, then all that pass evaluate byCriteria 2 so all candidates sorted in order of PBGT with

The strongest neighbour first

Handover triggered bytype 3 neighbour

Neighbour candidate list:–All algorithm 3 neighbours–All algorithm 1 and 2 neighbours–Any algorithm 4,5 and 6 neighboursPrefers type 3 neighbours, uses type 2neighbours as default candidates, then othersas last resorts

yes

no

In

Out

Handover triggered bytype 4,5 or 6 neighbour

Neighbour candidate list:–Remove algorithm 2 neighbours–Any algorithm 4,5 and 6 neighbours–Any algorithm 1 neighbours

Handover triggered by

imperative handovers or adj chan int

Neighbour candidate list:–Remove any algorithm 7 neighbours

which fail test:–All algorithm 1 and 2 neighbours–Any other neighbours

Out

yes

yes

no

no

Version 1 Rev 0Handover Margin Per Cause



4–60

Handover Margin Per Cause


Two handover margins have been configured per neighbour, specific to the cause of thehandover being performed. This cause specific handover margin will always be used indetermining if the neighbour should be excluded from the candidate list. The valueassigned is set by using the modify_neighbor command.

ho_margin_rxqual[n] (–63 to 63): The value to be applied to the PBGT calculation whenhandover cause is RXQUAL.

If PBGT – ho_margin_rxqual[n] < 0 , the neighbour will be excluded.

ho_margin_rxlev[n] (–63 to 63): The value to be applied to the PBGT calculation whenhandover cause is RXLEV.

If PBGT – ho_margin_rxlev[n] < 0 , the neighbour will be excluded

A per cell flag is used to determine if the cause specific margin should be used in thecandidate ordering procedure.

ho_margin_usage_flag = 0ho_margin[n] value (standard handover margin) will be used for sorting the candidatelist for RXLEV and RXQUAL handovers.

ho_margin_usage_flag = 1ho_margin_rxqual[n] or ho_margin_rxlev[n] will be used for sorting the candidate listfor RXQUAL or RXLEV handovers.

Individual neighbours can be guaranteed to not be the target of a particular type ofhandover by setting the cause specific margin to the highest value. The margin can beset to control the level at which the neighbour must be at before considering it as acandidate for a specific handover cause.

Application

With this feature, there is more flexibility since it gives the possibility to:

– Avoid the handover to unwanted neighbours where the call will be at risk.

– Sort the neighbours in the desired order, for going to the less congested cells or to the less interfered neighbours.

– Handover the calls only to good neighbours. For some of them this condition will be satisfied, even with negative PBGT to the server and for others, it will be necessary to have positive PBGT.

Version 1 Rev 0 Handover Margin Per Cause



4–61


SYS12_Ch4_30

Exclusion procedure:

Remove neighbor from candidate list if:PBGT– ho_margin(n)<0– _(Better Cell Handover)

Remove neighbor from candidate list if:PBGT– ho_margin_rxqual(n)<0– _ _

(UL/DL RXQUAL Handover)

Remove neighbor from candidate list if:PBGT– ho_margin_rxlev(n)<0– _ _

(UL/DL RXLEV Handover)

ho_margin_flag =0?

Sort neighbours based on:Pbgt – ho_margin_rxqual(n)

(ul/dl RXLEV Handovers)

Sort neighbours based on:Pbgt –ho_margin_rxlev(n)

(ul/dl RXQUAL Handovers)

Sort neighbours based on:Pbgt –ho_margin(n)

(All other handover causes)

Sort neighbours based on:Pbgt – ho_margin(n)

(All other handover causes)

Sorting Procedure

noyes

Version 1 Rev 0RXQUAL and Microcell Enhancements



4–62

RXQUAL and Microcell Enhancements

Timed Offset upon RXQUAL Handover

This feature addresses a particular situation that normally happens in the systems: it ispossible for the serving cell to have a much better RXLEV than a neighbour when a call ishanded over to the neighbour for RXQUAL reasons. This situation would likely result in apower budget handover back to the original serving cell. If the poor RXQUAL conditionstill exists, the call may experience a continuous bouncing between cells.

The ping–pong protection mechanism is implemented to help in this situation.

– When a channel is activated as the target channel of a RXQUAL handover,the bounce_protect_qual_tmr is started. Its value is the number of SACCHperiods during which bounce_protect_margin is applied.

– When a channel is activated as the target channel of a congestion handover,the bounce_protect_cong_tmr is started. Its value is the number ofSACCH periods during which bounce_protect_margin is applied.

– bounce_protect_margin : additional value added to the configuredho_margin of the source cell

An interference handover cause which results in an intercell handover due to lack ofresources on the serving cell will be treated in the same way as a RXQUAL handover.

bounce_protect_qual_tmr 0 to 127 SACCH periods Default = 0 (disabled)

bounce_protect_cong_tmr 0 to 127 SACCH periods Default = 0 (disabled)

bounce_protect_margin 0 to 127 (decibels) Default = 0

Version 1 Rev 0 RXQUAL and Microcell Enhancements



4–63

Handover for quality reasons

SYS12_Ch4_31

Serving Neighbour

Handover for quality reasons

GoodRXLEV

bounce_protect_qual_tmr = 20 (10s)

bounce_protect_margin = 20 (20dB)

20dB is added to the ho_margin for 10s to prevent the mobile beinghanded back to the original server for power budget reasons

Version 1 Rev 0Micro – Micro Quality Handover



4–64

Micro – Micro Quality HandoverWhen a RXQUAL handover condition exists, a layer indication for the serving cell and thetype of neighbour within the environment (identified by the PBGT algorithm utilised by thatneighbour) will be used to prioritise the microcell neighbours, thereby attempting tohandover, as well as maintain, the call within the microcellular layer. The lower thenumber for the layer indication, the larger the layer. Currently, this means that cell level 0is the macro layer, cell level 1 is the micro layer and cell level 2 is the pico layer. RXQUALhandovers can effectively be disabled to a specific neighbour by setting theho_margin_rxqual[n] for that neighbour to 63. Prioritisation and ordering of handovercandidates will only be performed if the functionality is enabled via theprioritize_microcell flag, and the bounce_protect_qual_tmr is not active.

Commands:

Element Min Max Default Value Definition Comments

layer_number 0 2 0 0 = Macrocell

1 = Microcell

2 = Picocell

per cell element

prioritize_microcell 0 1 1 0 = Disabled

Layer of serving cell will not impactsorting of candidate list.

1 = Enabled

Layer of serving cell will impactsorting of candidate list.

per cell element

Ordering

The following ordering will only be performed if the functionality is enabled via theprioritize_microcell flag , and the bounce_protect_qual_tmr (Timed Offset uponRXQUAL Handover) is not active. The dependency on bounce_protect_qual_tmr is toprevent a call from ping–pongs between two microcells if bad RXQUAL exists in both.

RXQUAL condition with call in microcell layer :

All neighbours which exceed rxlev_min[n] + Max (0,Pa)

All neighbours remaining after exclusion procedure considering handover margin percause

Neighbour types prioritized : (a)4,5,6 sorted by PBGT – ho_margin followed in the list by (b)3 sorted by PBGT – ho_margin followed in the list by (c)1,2 sorted by PBGT – ho_margin

RXQUAL condition with call in macrocell layer:

All neighbours which exceed rxlev_min[n] + Max (0,Pa)

All neighbours remaining after exclusion procedure considering handover margin percause

Neighbour types prioritised : (a)1 sorted by PBGT – ho_margin followed in the list by (b)2,3,4,5,6 sorted by PBGT – ho_margin

Version 1 Rev 0 Micro – Micro Quality Handover



4–65

Micro – Micro Quality Handover

sys12_ch05_35

layer_number = 0

layer_number = 1layer_number = 1

layer_number = 0

Neighbour types 4, 5, 6 followed by 3

Neighbour types 1 and 2Neighbourtype 5

Neighbour types 1 – Followed by 2,3,4,5 and 6Prioritize_microcell = 1

Version 1 Rev 0Handovers Adaptive



4–66

Handovers Adaptive

Overview

Normal handovers are triggered by a voting method such that if p from n of the mostrecent rolling averages meet a certain number, then the need for a handover isrecognised. However, this standard method may be too slow to catch a rapidlydeteriorating call. The alternative method of adaptive handovers now exists for Quality,Receive Level and Power Budget handovers. The adaptive handover method causeshandovers to be recognized based on a cumulative area rather than a vote. The adaptivehandover method enables handovers to occur more rapidly when conditions aredeteriorating quickly, but less rapidly when conditions are only marginally poor.

To achieve this, a cumulative total of the measurements are maintained. For Quality andReceive level adaptive handovers, this total is only maintained if the latest measurementexceeds the handover trigger threshold specific to that type of handover. The total is resetto zero any time there is no marginal need for a handover.

For adaptive Power budget handovers, the total is not reset, but maintained using a leakybucket criterion. This means the total will be incremented when the latest measurement(Pbgt(n)) exceeds the handover trigger threshold (ho_margin ), and decremented by thedifference, if it does not exceed the trigger level. A handover need is recognized in allcases when the cumulative total value exceeds the cumulative total trigger level, which isindependently set for each type of handover.

This enhancement to adaptive handovers allows for a third option to the previous twodescribed. With this enhancement, the operator has the option of setting the cumulativearea for adaptive power budget handovers on a per cell or per Neighbour basis. Thisoption is provided by modifying adap_ho_pbgt .

Version 1 Rev 0 Handovers Adaptive



4–67

Adaptive Handovers

� Quick reaction to fading calls

� Reacts less rapidly when conditions are onlymarginally poor

� Based on accumulated report measurements

� Types:

� Rxlev

� Rxqual

� PBgt: Per cell

Per neighbour

Version 1 Rev 0Adaptive Handovers



4–68

Adaptive HandoversThe three types of handover that are controlled by adaptive procedure are rxlev, rxqualand pbgt. For the latter type of handover, pbgt may be recognised on a per cell or perneighbour basis.

Adaptive Receive Level handovers .

Controlled by the parameter adap_ho_rxlev.

adap_ho_rxlev specifies whether the system allows adaptive receive level handovers.At each measurement report the cumulative area are updated and compared to acumulative trigger. If the area is greater than the cumulative power adaptive receive level(rxlev) trigger a need for a handover is recognized.

0 Disables adaptive receive level handovers at the location.

1 Enables adaptive receive level handovers at the location.

The level set in the parameters adap_trigger_rxlev_dl and adap_trigger_rxlev_ultriggers the handover. Range of both is 0–255, which refers to a cumulative total ofsequential measurements from the HDPC process. At each new measurement reportaverage (hreqave period) the rxlev of the server is compared against the lower handoverthreshold for uplink (or downlink).

If the level of the server goes below the threshold (in dBs) then:

rxlev_cumulative_area = rxlev_cumulative_area + (l_rxlev_xx_h – rxlev_xx )

xx = ul or dl

If the level of the server goes above the threshold (in dBs) then:

rxlev_cumulative_area is reset to zero.

If the rxlev_cumulative_area exceeds the adap_trigger_rxlev_xx then a handovercause of rxlev is generated for that call.

Version 1 Rev 0 Adaptive Handovers



4–69

Adaptive Receive Level Handovers

SYS12_Ch4_37

l_rxlev_xx_h = 20 (–90dBm)

xx = ul or dl

adap_trigger_rxlev_xx = 24

0

–47dBm

–110dBm

63

–90dBm20

rxlev_xx = 15 (–95dBm)

1st Av measurement report, acc area = 0

Cumulative area = 0 + (20 – 15) = 5

2nd Av measurement report, acc area = 5


Cumulative area resets to 0 asserver gone above the threshold

3rd Av measurement report, acc area = 0


Cumulative area = 0 + (20 – 5) = 15

4th Av measurement report, acc area = 15


Cumulative area = 15 + (20 – 10) = 25

Cumulative area exceeds adap triggerhence handover CV rxlev generated

Server Neighbour

Version 1 Rev 0Adaptive Receive Quality Handovers



4–70

Adaptive Receive Quality HandoversControlled by the parameter adap_ho_rxqual.

adap_ho_rxqual (0 Disables, 1 Enables) specifies whether the system allows adaptivequality handovers. At each measurement report the cumulative area is updated andcompared to a cumulative trigger. If the area is greater than the cumulative poweradaptive quality (rxqual) trigger a need for a handover is recognized.

The adap_trigger_rxqual_xx parameter specifies the cumulative trigger level foradaptive rxqual handovers. When the threshold set by this parameter is exceeded, thesystem performs a quality handover. The range is 0 – 65535.

(where xx = ul or dl )

The adaptive handover technique has an alternative set of parameters for use in hoppingcells:

adap_trigger_hop_rxqual_xx , which specifies the trigger threshold fordownlink rxqual for calls that are frequency hopping.

At each new measurement report average (hreqave period) the rxqual of the server iscompared against the lower handover threshold for uplink (or downlink).

If the rxqual of the server goes below the threshold (either by quality bands or BER) then:

rxqual_cumulative_value = rxqual_cumulative_value + (rxqual_xx – l_rxqual_xx_h)

If the rxqual of the server goes above the threshold (in dBs) then:

rxlev_cumulative_area is reset to zero.

If the rxlev_cumulative_area exceeds the adap_trigger_rxqual_xx then a handovercause of rxqual is generated for that call.

Hopping Parameters

When the cell is frequency hopping two parameters exist so the rxqual adaptivehandovers can be optimised. For non hopping carriers the dasebase parametersadap_trigger_rxqual_xx is used. But for hopping carriers where a lower level of BERcan be tolerated two other database parameters exist.

chg_element adap_trigger_hop_rxqual_dl <value> <location>

chg_element adap_trigger_hop_rxqual_dl <value> <location>

The range is 0 – 65535

Version 1 Rev 0 Adaptive Receive Quality Handovers



4–71

Adaptive Receive Quality Handovers

sys12_ch05_38

Server Neighbour

1st Av measurement report, acc area = 0

rxqual_xx = 453

Cumulative area 0+(453 – 400) = 53

2nd Av measurement report, acc area = 53

rxqual_xx = 226

Cumulative area resets to 0 asserver gone above threshold

3rd Av measurement report, acc area = 0

rxqual_xx = 905

Cumulative area = 0 + (905 – 400) = 505

4th Av measurement report, acc area = 505

rxqual_xx = 905

Cumulative area = 505 + (905 – 400) = 1010

Cumulative area exceeds adap triggerhence handover CV rxlev generated

7

0.14

18.1

0

1

2

3

4

5

6

0.57

1.13

2.26

4.53

9.05

0.28

adap_trigger_rxqual_xx = 1000

alt_qual_proc = 0

400

Version 1 Rev 0Adaptive Power Budget Handovers



4–72

Adaptive Power Budget Handovers

Outline

Controlled by the parameter adap_ho_pbgt.

� 0 = Standard power budget algorithm enabled

� 1 = Adaptive handover algorithm enabled using per–cell cumulative area

� 2 = Adaptive handover algorithm enabled using per–neighbour cumulative area

Adaptive power budget handovers are enabled by the parameter adap_ho_pbgt , whichallows a choice between a per cell basis where the same trigger values are set for allneighbour cells (trigger set by adap_trigger_pbgt (0–255)), or on a per–neighbour basisset by adap_trigger_pbgt_nbr (0 –255) which sets the trigger level neighbour byneighbour.

When measurement reports exceed the trigger, the total is not reset, but maintainedusing a leaky bucket criterion. This means the total will be incremented when the latestmeasurement (Pbgt(n) ) exceeds the handover trigger threshold (ho_margin ), anddecremented by the difference, if it does not exceed the trigger level.

A handover need is recognized in all cases when the cumulative total value exceeds thecumulative total trigger level.

Cumulative Area

The Cumulative area is a calculation made by comparing the pbgt(n) with ho_margin(n)for every average. If pbgt(n) > ho_margin(n) then (for both per cell and per neighbouroptions):

The pbgt_cumul_area = pbgt_cumul_area + (pbgt(n) – ho_margin )

Or else if ho_margin(n) > pbgt(n)

The pbgt_cumul_area = pbgt_cumul_area – (ho_margin(n)– pbgt(n) )

Note: pbgt_cumul_area cannot be less than 0.

Per Cell: A handover need is recognised if:

pbgt_cumul_area > pbgt_trigger

Per Neighbour: A handover need is recognised if:

pbgt_cumul_area > adap_trigger_pbgt_nbr

Version 1 Rev 0 Adaptive Power Budget Handovers



4–73

Adaptive Power Budget handovers

SYS12_Ch4_39

Example

adap_trigger_pbgt_nbr = 10

ho_margin = 5

adap_trigger_pbgt_nbr = 20

ho_margin = 5

S

n1 n2

4

1

Cumulativearea n1

0

0

0–1348

0–3126

0–5–104

0–7–3–22

Cumulativearea n2

Pbgt (n2) –ho_margin

Pbgt (n1) –ho_margin

pbgt

(n2)

pbgt

(n1)

25

16

9

9591014

437812

115610

Handover

pbgt_cumulative_area = pbgt_cumulative_area + (pbgt(n) –ho_margin)

Pbgt_cumulative_area > adap_trigger_pbgt_nbr

Pbgt(n) > ho_margin

Version 1 Rev 0Example Application Scenarios for Handover Procedures



4–74

Example Application Scenarios for Handover ProceduresOpposite is an application example for handovers between microcells with variousrelationships. The table gives an example of how the Motorola algorithms might beapplied in these cases.

Imperative handover from microcell to macrocell

The macrocell is a type 2 neighbour for each of the microcells. This means that if animperative handover is generated whilst in one of the microcells, the macrocell will alwaysbe given high priority (see handover candidate ordering list).

Hand–down from macrocell to microcell (handover to a type 5 neighbour)

The 3 microcells are all specified as type 5 neighbours of the macrocell. This allows thepossibility of delaying the hand–down from the macrocell until the mobile has seen aconsistently high signal level from the microcell for a specified time. In this way, fastmobiles will not stay in a microcell long enough to trigger a hand–down.

Handover to a type 3 neighbour (round the corner handover)

Microcell 2 is specified to be a type 3 neighbour of microcell 1. This means that a mobiletravelling along route A will satisfy the condition for handover because the serving cellRXLEV threshold is crossed as the mobile turns the corner. A mobile travelling alongroute B, however, will not satisfy the condition for handover because the serving cellRXLEV will remain above the threshold.

Handover to a line–of–sight neighbour

Microcells 1 and 3 are line–of–sight neighbours,and in this case algorithm 4 is applied.This is used in preference to algorithm 1 since type1 neighbours would have an equalweighting with type 2 neighbours in the event of an RXQUAL handover.

Applying the algorithms

Care must be exercised in the application of these algorithms since the relations betweenthe microcells (LOS or round the corner) depends upon the path taken between them.Depending upon the RF planning, it may be possible to arrange that, having specified analgorithm tailored to one particular route between the cells, then any other route goes viaother cells. For example, this could be done to isolate possible areas of adjacent orco–channel interference in the network.

Version 1 Rev 0 Example Application Scenarios for Handover Procedures



4–75

Application Scenarios for Handover Procedures

1

2

3A

B

Microcells1,2 and 3

Macrocell AMacrocell B

sys12_ch05_46

CELL NEIGHBOUR ALGORITHM

Macro B 1

Macro A 1 5

2 5

3 5

Macro 2

1 2 3

3 4

Macro 2

2 1 3

3 3

Macro 2

3 1 4

2 3

Version 1 Rev 0Exercise



4–76

Exercise� The aim of this exercise is to complete a database with suitable levels (for

add_neighbor ) using the microcellular principles considered in the course. Thestrategy for all mobiles is that when idle, they are to be served by the macrocelllayer. Fast moving mobiles are to be discouraged from handing into the microcells.Slow moving mobiles in dedicated mode are to be served by the microcell layer.As well as using add_neighbor you may use add_cell of the neighbour if it is aninternal neighbour.

� The following information is to be considered:

� All cells are on separate sites

� Rxlev on street:MACROCELL –60dBmMICROCELL –75dBmIn building –80dBm

� Fast moving mobiles spend no more than ten seconds in the microcells (A SACCHmultiframe period is 480 msecs).

� Slow moving pedestrians move past the building containing cell 5 after 10s.

� All microcells are under the control of a separate BSC from that of the macrocell.

� All cells are in the same location area.

� The system is GSM 900.

� Consider the in–building microcell may radiate through the walls to the street.

� NCC for your network has number (0,4). You can choose a value of BCC for theBSIC.

– Serving Cell 0 frequency 45

– Macrocell 1 frequency 20

– Microcell 2 frequency 43



– Inbuilding Cell 5 frequency 42

� Complete the information you would enter for the neighbors add_cell (notprompted for external neighbours).

� hreqave is to be set on a per neighbour basis for rxlev(n) averages.

� ho_margin to be set on a per neighbour basis.

� Neither directed retry or congestion relief are enabled

� Concentric cells are not enabled

� Extended range cells are not enabled

� Assume for the purposes of this exercise that PBGT adaptive handovers are notemployed.

Version 1 Rev 0 Exercise



4–77

Microcellular Exercise

sys12_ch05_MicEx

PEDESTRIAN WALKWAY

FAST MS

MACROCOVERAGE(CELL 1)

INBUILDINGCELL 5

FAST MS MICROCELL 2 SERVER 0 MICROCELL 3

= ANTENNA

MICROCELL 4




4–78

add_neighbour

srccell_id xxx xx xxx xx0

neighbor_cell_id xxx xx xxx xx1

Placement _ _ _ _

list type _ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

add_cell (frequency)

frequency_type =

BSIC =

max_tx_ms =

rxlev_min_def =




4–79

add_neighbour



Placement _ _ _ _

list type _ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _


frequency_type =

BSIC =

max_tx_ms =

rxlev_min_def =




4–80

add_neighbour



Placement _ _ _ _

list type _ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _


frequency_type =

BSIC =

max_tx_ms =

rxlev_min_def =




4–81

add_neighbour



Placement _ _ _ _

list type _ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _


frequency_type =

BSIC =

max_tx_ms =

rxlev_min_def =




4–82

add_neighbour



Placement _ _ _ _

list type _ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _


frequency_type =

BSIC =

max_tx_ms =

rxlev_min_def =

Version 1 Rev 0 Database Parameters



4–83

Database Parameters

add_neighbor

The current add_neighbor command includes all parameters on the command line. Themicrocell feature will change the add_neighbor command to prompt for the necessaryinformation to enable the microcellular types.

Separate BA Lists

The separate BA lists allows the operator to select neighbours to be included in theBCCH Allocation on the SACCH and the BCCH. The BSS maintains two separate lists

ba_bcch This list is the BA sent in system information message type 2 on the BCCH. It is the list of frequencies in use by a given PLMN in a given geographical area. It is used by the MS for cell selection and reselection.

ba_sacch This list is the BA sent in system information message type 5 on the SACCH. It indicates to the MS which BCCH frequencies are monitored for handover purposes.

By maintaining two distinct BA lists, the operator is given the flexibility to vary thefrequencies the MS monitors in idle mode independent of the frequencies the MSmonitors as potential neighbours in dedicated mode.

It is possible to set a combined total of 64 distinct frequencies in the ba_bcch andba_sacch lists. Each of these frequencies can be included in one or both of these lists.However, the number is restricted to 32 frequencies in the ba_sacch . This limit isconsistent with the number of different frequencies the MS can report on in measurementreport messages based on the format of the messages. The ba_bcch may contain up tothe total of 64 distinct frequencies only if all the frequencies included in the ba_sacch areincluded in the ba_bcch .

Note 1:

The neighbor_cell_id may be placed with the string “test#” where “#” is a numberbetween 1 and 64. The addition of test neighbours are to add frequencies to theba_sacch and/or ba_bcch lists. Therefore, for test neighbours the placement will be anoptional parameter and ignored if entered and the frequency will be the only promptedparameter.

Note 2:

If the list_type is “ba_bcch ” and placement is “internal”, no data will be prompted.

Version 1 Rev 0Database Parameters



4–84

add_neighbor

Command name: add_neighbor

Security Level: 2

Function: Used to add one neighbour cell to another a source cell neighbour list

Parameters:

<src_cell_id> Cell identity of the cell to which a neighbor is being added.

<neighbor_cell_id> Cell identity of the cell specified as a neighbour to the source cell.

<placement> “internal” Specifies that the neighbour cell is inside the BSS.

“external” Specifies that the neighbour cell is outside of the BSS.

<list_type> “ba_bcch” Put neighbours frequency on the ba_bcch list.

“ba_sacch” Put neighbours frequency on the ba_sacch list.

“both” Put neighbours frequency on the ba_bcch and ba_sacch lists.




4–85

Add Neighbor Prompts TablePrompt Range Default Notes

Enable synchronization: 1 (Yes)

0 (No)

0 N/A for external neighbours

N/A if source cell is at aHorizonoffice BTS

Enter the neighbour cellfrequency type:

pgsm

egsm

dcs1800

pcs1900

gsm850

None N/A for internal neighbours.

Enter the BCCH frequencynumber:

1 to 124 for GSM900

0, 1 to 124, 975 to1023 for EGSM900

512 to 885 forDCS1800

512 to 810 forPCS1900

None

A value MUSTbe entered at thisprompt.

N/A for internal neighbours

EGSM BCCH frequencies 0,975 to 1023 are notavailable when theegsm_bcch_sd parameter isdisabled.

Enter base station identity code(bsic):

0 to 63 None



Enter MS transmit powermaximum:

5 to 39 (odd valuesonly) for PGSM andEGSM

0 to 30 (even valuesonly) for DCS1800

0 to 32 (even valuesonly) and 33, forPCS1900

None



Enter neighbour receive levelminimum:

0 to 63 rxlev_min_def ofneighbour cell

Required for externalneighbours

Enter neighbour handovermargin:

–63 to 63 ho_margin_defof neighbor cell

Required for externalneighbours

Refer to the description ofthe ho_margin_defparameter.

Does this neighbour have acarrier with an interferingfrequency?

0 (No)

1 (Yes)

0 (No) Only prompted ifinner_zone_alg for thesource cell is set to 2, andthe neighbour is beingadded to the SACCH list


Enter the threshold for inner zonehandover

0 to 63 0 Only prompted if “Does theneighbour have a carrierwith an interferingfrequency?” = 1 (yes).

Version 1 Rev 0Database Parameters



4–86

Prompt Range Default NotesEnter the margin for inner zonehandover

0 to 63 0 Only prompted if “Does theneighbour have a carrierwith an interferingfrequency?” = 1 (yes).

Enter the power budgetsurrounding cell hreqave:

1 to 31 8

Enable adjacent channelinterference avoidance test?:

0 (No)

1 (Yes)

0 (No) NA if microcell is notpurchased

Enter rxlev difference foradjacent channel interferenceavoidance test:

–63 to 63 0 NA if microcell is notpurchased

This prompt only applies ifthe previous answer was “1”

Enter the power budget algorithmtype:

1 to 7 1 N/A if microcell is notpurchased

Enter the adjacent channelinterference detection handovermargin:

–63 to 63 ho_margin_cell This prompt only appears ifpbgt_alg_type = 7.

Enter the uplink receive levelthreshold of the serving cell:

0 to 255 None


N/A if multi–layer handoversis not purchased and pbgt_alg_type � 3

Enter the downlink receive levelthreshold of the serving cell:

0 to 255 None N/A if multi–layer handoversis not purchased and pbgt_alg_type � 3

Enter the qualifying timethreshold:

0 to 255 0 SACCHperiods

N/A if multi–layer handoversis not purchased andpbgt_alg_type � 4

Enter the qualifying delay time: 0 to 255 0 SACCHperiods

N/A if multi–layer handoversis not purchased andpbgt_alg_type � 5

Enter the neighbour cell receivelevel threshold:

0 to 63 None



Enter the delay time: 0 to 255 0 SACCHperiods


Enter the handover static offset: 0 to 127 0 N/A if multi–layer handoversis not purchased and pbgt_alg_type � 6

Enter the handover dynamicoffset:

0 to 127 0 N/A if multi–layer handoversis not purchased andpbgt_alg_type � 6




4–87

Prompt Range Default NotesEnter neighbour congestionhandover margin:

–63 to 63

To disable congestionhandovers to thisneighbour, set thevalue to 63

ho_margin_cellof neighbour cell

Value should be less than orequal to the ho_margin_cellof the neighbour cell.

This prompt is onlypresented if directed retry orcongestion relief ispurchased.

Is directed retry allowed at thisexternal neighbour cell?:

1 = Yes

0 = No

1 N/A when adding internalneighbours

This prompt is onlypresented if directed retry orcongestion relief ispurchased.

Enter the Range of the neighbourcell:

normal

extended

Normal This prompt is onlypresented if the ExtendedRange Cells feature isunrestricted.


add_neighbour

In order that the correct integer values are added in the add_neighbor commandprompts, the following is useful:

In the prompts for timers in algorithms 4, 5 and 6. Then 0 to 255 equates to:

0 – SACCH multiframes= 0 secs

1 – SACCH multiframes= 480 msecs

2 – SACCH multiframes= 960 msecs

255 – SACCH multiframes= 122.4 secs

In prompts for thresholds in algorithms 3 and 5. Then 0 to 63 equates to:

0= –110 db

1= –109 db

2= –108 db

63= –47 db

In prompts for offsets in algorithms 6. Then 0 to 127 equates to:

0= 0 db

1= 1 db

2= 2 db

127= 127 db



5–1

Chapter 5

Capacity Enhancing Database

Version 1 Rev 0



5–2

Version 1 Rev 0 Capacity Enhancing Database



5–1

Capacity Enhancing Database

Objectives

On completion of this chapter the student will be able to:

� Discuss the use and implementation of directed retry and congestion relief

� Discuss the use and implementation of multiband

� Discuss the use and implementation of concentric cells

� Discuss the use and implementation of coincident multiband

� Discuss the use and implementation of single BCCH for dual band cells

� Discuss the use and implementation of extended range cells

Version 1 Rev 0Directed Retry



5–2

Directed RetryThe GSM implementation of standard directed retry allows the simultaneous handling ofcall setup assignment and handover procedures, by allowing a handover from an SDCCHto a TFC. Essentially this feature allows a MS to be handed from an SDCCH in one cellthat has no TFC channel capacity available at call setup (for that MS) to a TFC channelin another cell. This feature will not be activated unless the Assignment Request (for thatMS) is queued awaiting resource (i.e. All TFC resources in the cell are utilized).

It is possible to enable this feature such that it will only allow movement of an MS to cellsinternal to the BSS. This implementation has no impact on the A–interface signalling andfor this reason can be used with an existing MSC configuration. If this feature isimplemented to allow the MS to be handed to an external cell, then it requires theHandover Required message to carry a cause of directed retry.

To instruct the mobile to move the Handover Command carrying the channel modeelement is sent to the mobile. The channel mode element indicates to the mobile thatthe target channel supports, either speech, signalling or data. Of course a directed retryhandover will not be initiated unless the MS has reported a strong enough neighbour thatmeets a congestion relief criteria.

If directed retry is enabled and the BSS receives an Assignment Request and no TFCchannels are available then the Assignment Request is queued regardless of queuingbeing enabled in add_cell . If a TFC becomes available whilst the neighbours are beingprocessed then the queuing procedure is followed and the directed retry procedure isaborted.

If queuing is disabled in the BSS, the BSS will perform an internal queuing procedure, toa maximum of 25 calls. If queuing is enabled normal queuing shall be performed. If theBSS is using internal queuing, it will not send a Queuing Indication message. If allattempts at directed retry fail or no valid neighbours are reported then the TFC requestwill remain queued for the remainder of the relevant queuing timer.

Congestion relief

This feature consists of two congestion relief procedures (they are mutually exclusive)that can be enabled independently or in conjunction with Directed Retry. If the MSrequiring a TFC channel has not had the opportunity to report a neighbour that is goodenough to hand to, then the BSS may force another MS to handover from the congestedcell to free up a TFC channel. Of course this MS that is in an established call is onlyforced to handover if it has a neighbour that meets the congestion handover criteria. Ifno calls meet the congestion handover criteria, no handovers shall be initiated. Thefollowing options are available:

1. The maximum number of handovers initiated by this method is the number ofqueued requests in the congested cell.

2. The maximum number of handovers initiated by this method is the number of callsmeeting the congestion handover criteria in the congested cell.

Version 1 Rev 0 Directed Retry



5–3

Directed Retry

SYS12_Ch05_01

Serving Cell Neighbour Cell

MS queued regardless of whether queuing enabled or not

MS is on SDCCH, but wants TCH – non available

If there is a qualified neighbour, MS hands over

chg_element dr_preference <*> <bsc or 0> 0 = DR disabled1 = DR enabled

Version 1 Rev 0Congestion Handover Criteria



5–4

Congestion Handover CriteriaThe handover criteria is specified on a per cell basis. A handover margin is prompted inadd_neigbor , this is called the congest_ho_margin . If the latest rxlev_dl average ofany of the neighbour’s (for any MSs established in a call on the congested cell) meetcriteria 1 then they are further processed through a modified criteria 2:

pbgt– congest_ho_margin > 0

If any neighbours qualify using directed retry they can be used to handover the call to thebest neighbour.

To make it easier to handover to this neighbour in the case of congestion, this parametervalue should be less that the value of the handover margin(s) for handovers for radioreasons.

To disable congestion handovers to this neighbour, set the congestion handover marginto the maximum value +63.

In addition as the congest_ho_margin is usually set to negative values or 0 to facilitateDR handovers to neighbours with free resources. A positive congest_ho_margin wouldmean that the chances of finding a suitable neighbour would be minimal and thecongestion situation on the serving cell couldn’t be resolved effectively.

congest_ho_margin is a per neighbour parameter.

Valid Range: –63dB to 63dBDefault Value: None

Version 1 Rev 0 Congestion Handover Criteria



5–5

Congestion Handover Criteria

SYS12_Ch05_03

Server

N6N6

N5N5

N4N4

N3N3

N2N2

N1N1

All neighbours assessed to see if they meet criteria 1

Then ordered by pbgt – congest_ho_margin > 0

congest_ho_margin – 63 to +63 Default None

�

�

�

Version 1 Rev 0Enabling Directed Retry



5–6

Enabling Directed Retry

dr_preference

This is a chg_element command and is entered at the BSC, it is used to enable thefeature and to determine if the MSC is to be involved in the procedure as necessary. Byentering this command it determines if handovers can be forced to either internalneighbours or internal and external neighbours.

dr_standard_congest

This is a chg_element command that can only be entered on a per cell basis if thedr_preference is enabled at the BSC. This element enables or disables the standarddirected retry feature on a per cell basis. If this is command is enabled within the BSSthen the timer that that awaits an Assignment Complete message may requiremodification (i.e. increasing) in the MSC

dr_ho_during_assign

The BSS has the ability to enable and disable handovers triggered during an assignmentprocedure. These handovers would be from SDCCH to TFC in target cell. This featuredoes not effect the existing SDCCH to SDCCH handovers enabled in add_cell . If anintra–cell handover is needed during an assignment procedure and the assignmentrequest is queued, the BSS will perform the intra–cell handover. If an inter–cell handoveris needed during the assignment procedure and the Assignment Command has not beensent to the MS, an inter–cell handover is initiated. No Handover Performed messageshall be sent to the MSC as the Assignment Complete from the new cell contains all thenecessary information. If the Assignment Command has been sent to the MS, the BSSshall wait for either the Assignment Complete or Failure message from the MS beforeinitiating the handover.

Emergency and EGSM calls

If the emergency call pre–emption feature is enabled, emergency calls will not be handedover for congestion reasons unless all the calls in the cell are emergency calls. In thecase of all emergency calls in a cell, pre–emption cannot occur so a handover shall beattempted to service the incoming emergency call.

An MS on an EGSM channel shall not be handover from an EGSM frequency due tocongestion unless an EGSM capable MS is queued.

Microcellular purchasable option

When directed retry and or congestion relief are allowed, if a neighbour qualifies for acongestion handover prior to satisfying the microcellular algorithm selected for that cell, ahandover will be attempted (cause directed retry). A way of avoiding this would be togive the microcell neighbours a high congest_ho_margin .

TCH flow control

It is advisable, if the maximum benefit of directed retry or congestion relief is to be hadthe tch_flow_control should be disabled.

Version 1 Rev 0 Enabling Directed Retry



5–7

Enabling Directed Retry

SYS12_Ch05_04

BSC

BTS BTS BTS

chg_element dr_preference <*> <bsc or 0> 0 = DR Disabled (def)

1 = DR Enabled

Chg_element dr_standard_congest <*><site id><cell id>

0 = Disabled (

1 = DR enable

Entered per Cell

Entered at BSC

chg_element dr_ho_during_assign <*><site id> cell_number = <cell id> 0 = Ignore the need for handover

1 = Handover on queue

Handover during assignment for radio reasons

Version 1 Rev 0Directed Retry and External Handovers



5–8

Directed Retry and External Handovers

msc_preference (Default 0)

This element is used to set the message flow sequence used on the A–interface forexternal handovers during the assignment procedure. This element must align with theMSC expectations. The MSC implementation may depend on whether queuing isenabled in the cell. The cause value sent to the MSC can be set according to whetherdirected retry is supported by the MSC. This parameter requires the directed retry ormultiband operation to be enabled.

chg_element dr_chan_mode_modify <value> 0 or bsc (Default 0)

This element is entered at the BSC and determines the need for a channel mode modifyprocedure after a successful handover in which the channel mode changed ( GSM 04:08sect 7.3.7 ). The BSS shall read this database parameter only in the case of asuccessful handover in which the channel mode changed, the MS is phase 1, and thenew channel mode is full rate speech. Typically changing the channel mode during ahandover occurs only during a directed retry handover that has successfully completed tothis BSS during directed retry procedure. This is required as some MSs cannot interpretthe channel_mode element of the handover_command .

Valid Range 0 = disabled, 1 = Enabled

chg_element handover_required_curr_ch <value> 0 or bsc(Default 0)

This parameter must align with the settings of the MSC regarding the contents of theHandover Required message from the BSS. This parameter is set on a per BSS basis, itdetermines if the current channel information element is included in the HandoverRequired message.

This element is found in GSM08:08.

The target BSS on receipt of a Handover Required message composes the requestedchannel type with the current_channel_element and if they are different it will includethe channel_mode_element in the handover_command . This is done so that the MSscan determine whether that are moving to a speech, data or signalling channel.

Valid Range 0 = Not included, 1 = Included

modify_neighbor <source cell><neighbor cell> dr_allowed 1

Allows a directed retry to an external neighbour during the assignment procedure. Anexternal handover may only be initiated if either the dr_standard_congest ordr_ho_during_assign parameter is enabled. This attribute is only valid for SACCHneighbours.

Version 1 Rev 0 Directed Retry and External Handovers



5–9

Directed Retry and External Handovers

SYS12_Ch05_05

BSS BSS

MSC

chg_element msc_preference <*> <site id> cell_number = <cell id>

0 = Directed Retry is supported in the BSS but not across theA–Interface

1 = Directed Retry is supported within the BSS. The only A–interface impact is the Assignment Complete message,which contains the optional Cell ID if the Cell ID changesduring the assignment.

2 = The BSS sends the Handover Required message withthe cause ”directed retry” to the MSC.

3 = The BSS sends the Handover Required message withthe cause of the handover to the MSC (for example,BetterCell).

4 = The BSS sends an Assignment Failure message with

Required message with cause ”directed retry” to theMSC.

5 = The BSS sends an Assignment Failure message with thecause ”directed retry” and then sends a Handover Requiredmessage with the cause of the handover to theMSC (forexample, Better Cell).

6 = The BSS sends a Handover Required message with cause”directed retry” and then sends an Assignment Failuremessage with cause ”directed retry” to the MSC.

7 = The BSS sends a Handover Required message with thecause of the handover (for example, Better Cell) and thensends an Assignment Failure message with cause ”directedretry” to the MSC.

AssignmentComplete

the cause ”directed retry” and then sends a Handover

Version 1 Rev 0Congestion relief



5–10

Congestion reliefCongestion relief is an optional feature which is available as an alternative to Directedretry for the case of a congested cell. This feature differs in that it chooses the bestcandidate from all existing calls in the cell to be moved to the alternate cell thus freeingTCH’s in the congested cell. This can result in better overall system quality compared toDirected retry because the best handover candidate is chosen instead of the candidaterequesting a TCH.

It consists of two congestion relief procedures (they are mutually exclusive) that can beenabled independently or in conjunction with Directed Retry. If the MS requiring a TFCchannel has not had the opportunity to report a neighbour that is good enough to hand to,then the BSS may force another MS to handover from the congested cell to free up aTFC channel. Of course this MS that is in an established call is only forced to handoverif it has a neighbour that meets the congestion handover criteria. If no calls meet thecongestion handover criteria, no handovers shall be initiated. The following options areavailable:

1. The maximum number of handovers initiated by this method is the number ofqueued requests in the congested cell.

2. The maximum number of handovers initiated by this method is the number of callsmeeting the congestion handover criteria in the congested cell.

Version 1 Rev 0 Congestion relief



5–11

Congestion Relief

SYS12_Ch05_06




Another MS that is best qualified, hands over

chg_element ho_exist_congest 1 <site> cell_number = <cell id>




All the MSs that qualify, handover

chg_element ho_exist_congest 2 <site> cell_number = <cell id>

Type 1

Type 2

Version 1 Rev 0Congestion Relief – Standard Parameters



5–12

Congestion Relief – Standard ParametersThe main O&M impacts of this feature are to the BSS database with several BSS, Celland Neighbour parameters, some of which are shared with the Directed Retry feature.

Database Parameters

ho_exist_congest

This parameter determines if attempts to handover existing calls on a TCH will beinitiated in the case of an MS needing a TCH when there are none available in that cell.This parameter indicates either to attempt to handover as many calls as the number ofqueued assignment requests (if set to 1) or attempt to handover as many calls as meetthe congestion handover criteria (if set to 2). It concerns a cell.

Valid Range: 0,1 or 2Default Value: 0

If set to 0, the functionality is disabled.

congest_ho_margin

This parameter is used in the case of a congestion handover. To make it easier tohandover to this neighbour in the case of congestion in the current cell, this parametervalue should be less that the value of the handover margin(s).

To disable congestion handovers to this neighbour, set the congestion handover marginto the maximum value.

Valid Range: –63dB to 63dBDefault Value: None

tch_congest_prevent_thres

This per cell parameter specifies the level of overall TCH utilisation by any MS in a givenCell, at which the Congestion Relief procedure is initiated. The parameter is expressedas a percentage.

Valid Range: 1 to 101 Default Value: 100

If set to 100 it means congestion relief will be triggered when attempting to use the lastresource. If set to 101 it means congestion relief can only will be triggered when there isno resources left.

mb_tch_congest_thres

Used to control the percentage point at which Multiband Mobile Stations will start to beredirected to the preferred band. The BSS does not allow an incoming band preferencehandover should the servicing of that handover cause this percentage to be exceeded.

Valid Range: 1 to 101Default Value: 100

Timers

valid_candidate_ period

The BTS (RRSM) timer valid_candidate_period specifies the duration for whichcandidate channels for handover due to congestion are kept, before querying again fornew ones.

Valid Range: 0 to 1000000 Default Value: 4000 milliseconds

Version 1 Rev 0 Congestion Relief – Standard Parameters



5–13

Congestion Relief – Standard Parameters

SYS12_Ch05_07


Neighbour cell must pass criteria 1 to be used as target

pbgt(n) – congest_ho_margin > 0

tch_congest_prevent_thres = 90

ho_exist_congest = 1

Pbgt(n) = –2congest_ho_margin = –5

Mobileattempts toset up call

in cell

valid_candidate_period = 4000

Version 1 Rev 0Congestion Relief – Type 2 Parameters



5–14

Congestion Relief – Type 2 ParametersAdvanced Congestion Relief defines new handover procedures to select active calls tobe handed over to relieve congestion in the cell.

These new procedures take the form of expanding the decision process for handover toinclude the state of congestion at the target cell and incorporate the added dimension oftime over which the decision is to be implemented. For example, target cells will notaccept a congestion relief handover that puts itself into a congested state, resulting infurther congestion procedures being invoked. Excessive handovers are thereforeeliminated.

A source cell will not attempt a congestion relief handover, for a period of time, to a targetcell that had rejected a previous handover attempt. The time period may be specified bythe operator or as a default, may be set to the time between the onset and completion ofa congestion relief procedure. This protects the system from experiencing excessivehandover attempts, as well as resulting in a reduction in signalling.

congest_at_source

Used to control how a given cell behaves should it be unable to force a given imperativehandover

Valid Range: 0,1 Default Value: 1

If set to 0: The system takes no actions if a given candidate rejects a handover.

If set to 1: if a congestion relief handover is needed, the source Cell retries candidateswhich were previously unable to serve the handover request.

congest_at_target

Used to control how a given cell behaves should it reject a handover request (either animperative or congestion relief attempt).

Valid Range: 0,1 Default Value: 1

If set to 0: The system will take no action if the Cell reject a handover request.

If set to 1: The system will invoke Congestion Relief procedures if this cell rejects ahandover request. If a BSS target cell accepts an incoming handover due to congestionrelief and this handover itself triggers the target cell congestion relief procedures, thattarget cell does not trigger any handover attempts back to the source cell which triggeredthe congestion relief to begin with.

enhanced_reliefThis database parameter was introduced at GSR5 and when enabled removes rejectionof non imperative handovers when congest_at_target is set to 1.

Valid Range: 0,1Default: 0

ext_rtry_cand_prd timer

Used to control the time between successive attempts to handover to a particularinter–BSS target cell which had previously rejected a handover attempt (either animperative or congestion relief attempt).


rtry_cand_prd timer

Used to control the time between successive attempts to handover to a particularintra–BSS target cell which had previously rejected a handover attempt (either animperative or congestion relief attempt).


Version 1 Rev 0 Congestion Relief – Type 2 Parameters



5–15

Congestion Relief – Type 2 Parameters

SYS12_Ch05_08

congest_at_source = 1....Retries after rtry_cand_period = 4000 (def)

For external neighbours ext_rtry_cand_period = 4000 (def)

Neighbour selection criteria is the same as Type 1, with theaddition of procedures if a handover attempt is rejected

chg_element ho_exist_congest 2

BSC BSC

Serving CellNeighbour CellNeighbour Cell

If congest_at_target =1, then initiate congestion relief procedures inthat cell, when it rejects a handover attempt

Neighbour Cell

Version 1 Rev 0Associated Congestion Parameters



5–16

Associated Congestion ParametersWhen performing a handover to a new cell, due to congestion problems in the servingcell, it is possible that the serving cells rxlev could be much better than the target cellsrxlev. Thus, after arriving in the target cell, the mobile could immediately hand over backto the original server due to PBGT or rxlev, followed very quickly by another congestionhandover and so on. This condition is known as ping–pong or bouncing.

To cure this problem, an extra handover margin bounce_protect_margin can be addedto the ho_margin(n) for a defined period of time bounce_protect_cong_tmr in thetarget cell after a channel is activated in that cell. This makes it more difficult for themobile to hand over back to the original cell after a congestion handover.

The functionality of the bounce_protect_margin is shared with bounce protect marginsapplied for rxqual reasons (covered in SYS03).

chg_element bounce_protect_margin <*><cell_desc>

<*> = 0 to 127 dB (default = 0)

chg_element bounce_protect_cong_tmr <*><cell_desc>

<*> = 0 to 255 (default = 0)

Version 1 Rev 0 Associated Congestion Parameters



5–17

Associated Congestion Parameters

Neighbour CellNeighbour CellServing CellServing Cell

10dB added to ho_margin(n)for 20 SACCHfor 20 SACCH

sys12_ch6_08achg_element bounce_protect_cong_tmr 20 <cell_desc>

chg_element bounce_protect_margin 10 <cell_desc>




5–18

Concentric CellsConcentric Cells is an optional feature which provides cell resource partitioning using theconcept of the concentric cell structure (outer and inner zones) to allow for tighter re–usepatterns and increased frequency economy.

This feature describes the use of a single BCCH using interference estimation ormeasurement to move traffic between the conventional macrocell underlay (Outer zone)and the super reuse layer (Inner zone).

Concentric Cell is an elegant and simple technique in which the size of cells on the superre–use layer (inner zone) is self–governed by interference or by the power that thecarriers on the inner zone transmit.

With this feature the operator may configure non–BCCH carriers within a cell to have asmaller coverage area. The carriers equipped within a cell may be grouped into twozones:

� Zone 0: Also referred to as the “outer zone”, is reserved for carriers that maybroadcast at the maximum transmit level defined for the cell.

� Zone 1: Also referred to as the “inner zone”, may be defined with non–BCCHcarriers transmitting lower power than the BCCH carrier, or having a tighter reusepattern that reduces the useful coverage area of the carrier.

The Mobile Station connected to Zone 0 must meet specific criteria before it can beassigned a traffic channel configured on a carrier in Zone 1 and vice versa. There are twodifferent “use algorithms”, specified by the operator on a per cell basis, to trigger thetransitions between the two zones of the cell.

� Power Based Concentric Cells: Inner zone carriers transmit less power than outerones and the transitions between zones are based on absolute level thresholds.

� Interference Based Concentric Cells: Inner and outer zone carriers transmit all thesame power within and the transitions between zones are based on someinterference conditions. These interference conditions are protection marginsagainst potential interfering neighbours.

The use of a single BCCH implies that the carriers placed in the outer zone are availablein the whole cell coverage area whereas the inner zone carriers are only available in arestricted area close to the site location. The signalling previous to the call set–up isestablished in the outer zone and whenever it is possible to move to the inner, the call istransferred to the inner carriers.

The Concentric Cell feature is basically a capacity enhancement feature. The possibilityof implementing tighter reuse patterns in the area close to the antenna site permits toincrease the capacity at the same time that quality is guaranteed by the use ofinterference estimation algorithm

Multiband

From software release GSR 5.0 multiband operation of concentric cells is allowed. Forexample if DCS1800 is being added to an existing GSM900 network, the existingGSM900 BCCH plan can be used, since there is no need to plan DCS1800 BCCHs when1800MHz carriers are added. For this feature to be efficient the network should havesufficient number of multiband–capable mobiles and equipment should be collocated andsynchronized. (InCell cabinets cannot be mixed with M–Cell/Horizon cabinets in thesame logical area). In the example described above, all mobiles must be at leastGSM900 capable to access the system. Since the BCCH carriers are defined in theGSM900 band, single band DCS1800 mobiles will be unable to access the system.




5–19

Concentric Cells

SYS12_Ch01_14

Zone 0 – Outer Zone

Zone 1 – Inner Zone

BCCHBroadcast at max txlevel defined for thatcell

Non – BCCHTransmitting at

lower power thanBCCH or

Having a tighterreuse pattern that

reduces the usefulcoverage area of

the carrier

Other non_BCCH carriers

Multiband Operation of Concentric CellsSupported from GSR 5.0

Version 1 Rev 0Power Based Concentric Cells



5–20

Power Based Concentric CellsTo enable concentric cells and the whether a power, interference or dual band operationis being selected, is set by the database parameter:

inner_zone_alg = <*> Where 0 = Disabled

1 = Power based use algorithm

2 = Interference based use algorithms

3 = Dual band in use

In the power based intra–cell handover algorithm carriers in the inner zone are givenreduced maximum uplink and downlink transmit levels, which define the coverage area ofthe inner zone.

The decision to move traffic between zones is based on the downlink and uplink receivelevels with respect to the serving cell, as well as database parameters, which areprompted when inner_zone_alg = 1 .

� ms_txpwr_max_inner

Valid Range: PGSM, EGSM and GSM 850 5 to 39 dBm Default value: max_tx_ms

DCS 1800 and PCS 1900 0 to 30 dBm Default value: max_tx_ms

� zone_ho_hyst

Valid range: 0 to 30 Default = 0

� rxlev_dl_zone


� rxlev_ul_zone


Handover to Inner ZoneA handover is initiated when both the uplink and the downlink receive level averages aregreater than the sum of the respective uplink or downlink thresholds defined for the innerzone plus the per cell hysteresis for interzone handover plus the difference between thecurrent uplink/downlink transmit power and the maximum uplink/downlink transmit powerof the inner zone carrier.

Initiate handover into the inner zone if the following is true for the inner zone carrier(s):

rxlev_dl > rxlev_dl_zone + zone_ho_hyst + (bs_txpwr – bs_txpwr_max_inner)andrxlev_ul > rxlev_ul_zone + zone_ho_hyst + (ms_txpwr – ms_txpwr_max_inner)

where: rxlev_dl/ul_zone = minimum rxlev in inner zone

–110dBm(0) to –47dBm(63)

bs/ms_txpwr = current tx power in outer zone (max_tx_bts and max_tx_ms ). Non–bcch carriers can use adaptive pwr control.

bs_txpwr_max_inner = trx maximum power capability – trx_pwr_red (Set in RTF equipage)

This is the reduced power downlink due to being an inner cell. Each carrier can have adifferent trx_pwr_red value, giving multiple sub–zones inide zone 1.

Version 1 Rev 0 Power Based Concentric Cells



5–21

Power Based Concentric Cells – Handover to Inner Zone

SYS12_Ch05_10

rxlev_dl_zone = 33 (–77 dBm)

rxlev_ul_zone = 36 (–74 dBm)

zone_ho_hyst = 3 dB

trx_pwr__red = 3 (6dB)

inner_zone_alg = 1

ms_txpwr_max_inner = 31 dBm

Zone 0

Zone 1

Mobile PowerClass = 4

bs_txpwr_max_inner = trx max power

capability – trx_pwr_red

rxlev_dl = –65 dBm

rxlev_ul = –63dBm

rxlev_dl > rxlev_dl_zone + zone_ho_hyst + (bs_txpwr – bs_txpwr_max_inner)

–65 > – 77 + 3 + (43 – (43 – 6))

–65 > –68

rxlev_ul > rxlev_ul_zone + zone_ho_hyst + (ms_txpwr – ms_txpwr_max_inner)

–63 > –74 + 3 + (33 –31)

–63 > –69

Version 1 Rev 0Power Based Concentric Cells – HO to Inner Zone Power Level



5–22

Power Based Concentric Cells – HO to Inner Zone Power Level

Overview

Using the power based algorithm, the operator may set each carrier in the inner zone todifferent maximum downlink transmit power levels. Using this configuration, the BSSshall perform handovers between inner zone carriers based on the same algorithms usedto perform handovers between zones. By utilizing this functionality, the operator caneffectively have multiple sub–zones within zone 1. However, all carriers defined to be inzone 1 share the same maximum uplink transmit level. All carries defined to be in zone 0shall have maximum downlink transmit level defined by the BCCH power level and themaximum uplink transmit level as defined per cell in the database.

Handover to Inner Carrier

The HDPC provides the minimum and maximum power level that satisfies the twohandover algorithms. Call processing also utilizes these values to select a channel on acarrier that has the lowest maximum transmit level that is within the given range. Themaximum power level for a candidate carrier is one power level weaker than the servingcarrier and is calculated by incrementing the serving carriers maximum transmit powerlevel:

maximum power level = serv_txpwr_max + 1

Where: serv_txpwr_max = trx_pwr_red defined for the serving carrier

The minimum power for the candidate carrier is derived from the downlink transmit powercriterion as follows:

minimum power > rxlev_dl_zone + zone_ho_hyst + bs_txpwr – rxlev_dl

All parameters in the above equation are converted into dBm before calculation of theminimum power. The minimum power is then converted from dBm to level units. If thecomputed value falls between two different levels in the conversion table, the strongerpower level shall be used

Prior to sending the zone handover recognized message, the handover process mustverify that the calculation range is valid, and that the cell has at least one carrier withinthe calculated range. To facilitate this process a list of carriers is provide in descendingorder by TRX power level reduction value (trx_pwr_red ) Therefore last entries will beouter zone carriers. The call does not qualify for an inner carrier handover if the minimumpower level turns out to be stronger than the maximum power level or no carriers in thelist has a trx_pwr_red value within the minimum and maximum power level range,inclusively.

If the call qualifies for both an inner carrier handover and the standard interferencehandover, the max power level is adjusted to cell max, max_tx_bts This allows CP toassign the call to an outer carrier when there are no resources available for the innercarrier handover and thereby satisfying the standard interference handover requirement.

Version 1 Rev 0 Power Based Concentric Cells – HO to Inner Zone Power Level



5–23

Power Based Concentric Cells – Handover to Inner ZonePower Level

SYS12_Ch05_11

Zone 1

serv_txpwr_max = 2 (39 dBm)39 dBm


rxlev_dl = 60 (–50 dBm) rxlev_dl = –50 dBm

bs_txpwr = 3 (37 dBm)

37 dBm

zone_ho_hyst = 4 dB

Zone 0

min power > rxlev_dl_zone + zone_ho_hyst + bs_txpwr – rxlev_dl

> –80 + 4 + 37 – (–50)

> 11 dBm (level 16 – in between levels so . . . )

min power = 15 (13 dBm)

max power level = serv_txpwr_max + 1

= 2 + 1

= 3 (37 dBm)

13 dBm

Handovers intoinner carrierswith maximumpower levels of15 to 3 areallowed




5–24

Concentric Cells

Handover to Outer Zone

A handover is initiated when either the uplink or the downlink receive level average isbelow the respective uplink or downlink threshold defined for the inner zone and a furtherincrease of the transmit power is not allowed.

Initiate handover into the outer zone if the following is true:

rxlev_dl < rxlev_dl_zone AND bs_txpwr = bs_txpwr_max_inner

OR

rxlev_ul < rxlev_ul_zone AND ms_txpwr = ms_txpwr_max_inner

where:

rxlev_ul/dl_zone = minimum rxlev in inner zone

–110dBm(0) to –47dBm(63)

bs_txpwr_max_inner = TRX maximum – power trx_pwr_red

This is the reduced power downlink due to being an inner cell.

ms_txpwr_max_inner = specifies the max power an MS can use in the inner zone of a

concentric cell, see W23

bs/ms_txpwr = current tx power in inner zone




5–25

Concentric Cells – Handover to Outer Zone

SYS12_Ch05_12

Zone 0

Zone 1

Zone 0

Zone 1

Zone 0

Zone 1


rxlev_ul_zone = 36 (–74 dBm)

trx_pwr_red = 3 (6dB)

ms_txpwr_max_inner = 31 dBm

bs_txpwr_max_inner = trx max power

capability – trx_pwr_red

rxlev_dl < rxlev_dl_zone AND bs_txpwr = bs_txpwr_max_inner

rxlev_ul = – 76 dBm

rxlev_dl = – 76 dBm

–76 < –77 AND 27 = (33 – 6) X

OR

rxlev_ul < rxlev_ul_zone AND ms_txpwr = ms_txpwr_max_inner

–76 < –74 AND 31 = 31

Mobile PowerClass = 4

inner_zone_alg = 1

Version 1 Rev 0Interference Based Concentric Cells



5–26

Interference Based Concentric Cells

Overview

The interference algorithm is based on the interference estimation in the inner zone. Thehandover to the inner zone is triggered if no interference is expected from any neighbour,and as soon as interference is expected from any neighbour the call makes handover tothe outer zone.

The interference estimation is just a modified power budget calculation with all theinterfering neighbours. To be free of interference from a particular neighbour, the powerbudget with the serving cell must be better that the one with the neighbour in a threshold(inner_zone_threshold ) and a margin (inner_zone_margin ) to prevent ping–pong.

So, with this new configuration, the thresholds were defined on a per neighbour basis,and depending on the type of interference expected from the neighbour: Co–channel oradjacent–channel interference, and the influence of the cell: front to front, back to front orfront to back interference.

The database parameter that indicates that the neighbour uses an interfering frequency(i.e. may be adjacent or co–channel) is:

interfering_nbr (set in add_neighbor )

Range: 0 to 1

0 = no

1 = yes

Version 1 Rev 0 Interference Based Concentric Cells



5–27


SYS12_Ch05_13

Serving Cell

Neighbour 1 Neighbour 3

Neighbour 2

Power budget calculated for all neighbours

Handover to the inner zone if no interference from any neighbour

As soon as interference expected handover to the outer zone

To be free of interference from a particular neighbour: pbgt(s) must be better thanpbgt (n)s + threshold + margin

Thresholds set per neighbour

Version 1 Rev 0Interference Based Concentric Cells



5–28


Power Budget Calculation

For concentric cell inter zone handovers, the usual power budget formula is modified toremove consideration of the mobiles transmit power capacity, as follows:

Pbgt (n)’ = (ms_txpwr_max – rxlev_dl – pwr_c_d) – (ms_txpwr_max (n) – rxlev_ncell (n))

where: pwr_c_d = maximum downlink Tx power in outer zone – actual downlink Txpower

ms_txpwr_max = maximum mobile transmit power defined per cell

An assumption is made at this stage that the difference between the serving cellmaximum BS transmit power level and the neighbour cell maximum BS transmit powerlevel is equal to the difference the serving cell maximum MS transmit power level and theneighbour cell maximum MS transmit power level.

(i.e. ms_txpwr_max – ms_txpwr_max(n) = bs_txpwr_max – bs_txpwr_max(n)).

This is because bs_ txpwr_max(n) is not presently available in the database and the MSpower levels are used in the equation instead of the BS power levels.

Mobile Power Factor

Since the focus of this algorithm is to prevent the MS from getting into a position where itcan experience or cause interference, an additional factor is calculated to account for themobile reporting poor quality and the decision_alg_num database parameter being setto 1, to allow a power increase due to quality even when the rxlev is above its upperthreshold. This factor is defined here and used in the equations below:

ms_pwr_factor = rxlev_ul + (ordered_power_level – used_power_level) –

l_rxlev_ul_p

This calculation incorporates pending power control changes and, to be conservative, isbased on the lower end of the power box and should deter the MS from being served bythe inner zone.

Version 1 Rev 0 Interference Based Concentric Cells



5–29



rxlev(n1) = –90 rxlev(n2) = –80

rxlev (s) = –70

ms_txpwr_max = 33ms_txpwr_max = 33

max_tx_ms = 33

pwr_c_d = 0

Pbgt(n)’ = (ms_txpwr_max – rxlev_dl – pwr_c_d) – (ms_txpwr_max(n) – rxlev_ncell(n))Pbgt(n1)’ = (33 – (–70) – 0) – (33 – (–90)) = –20dBPbgt(n2)’ = (33 – (–70) – 0) – (33 – (–80)) = –10dB

0

63

35 400

7

0

1

2

4

5

0.14

18.1

3

6

0.57

1.13

2.26

4.53

9.05

0.28


decision_alg_type =1

used_power_level = 27dBmordered_power_level = 29dBm

– 47dBm

rxlev_ul = –70dBm

–74dBm (l_rxlev_ul_p)

– 110dBm

ms_pwr_factor = rxlev_ul+(ordered_power_level – used_power_level) – l_rxlev_ul_p–70 + (29 – 27) – (–74)

= 6dB

rxlev (n2) = –75rxlev (n2) = –65

rxlev (s) = –70

sys12_ch06_p29

Version 1 Rev 0Interference Based Algorithm – Handover to Inner Zone



5–30

Interference Based Algorithm – Handover to Inner ZoneIn deciding whether a call is suitable to be served by an inner zone channel, the BSS(HDPC) must satisfy itself that both of the conditions below are true. However, it shouldbe noted that they must be true in relation to all neighbours that contain a co– oradjacent–channel interfering carrier frequency.

Uplink Criteria: (Checks if the mobile is going to interfere with neighbour cells)

pbgt(n) +ms_pwr_factor + inner_zone_threshold(n) +inner_zone_margin(n) ≤ 0

and

Downlink Criteria: (Checks if the neighbours are going to interfere with the mobile)

rxlev_dl + pwr_c_d – (rxlev_ncell(n) + inner_zone_threshold(n) +

inner_zone_margin(n)) ≥ 0

Where:

inner_zone_threshold(n) Range 0 to 63

and

inner_zone_margin(n) Range 0 to 63

and are per neighbour database defined values.

Version 1 Rev 0 Interference Based Algorithm – Handover to Inner Zone



5–31

Interference Based Algorithm – Handover to Inner Zone

SYS12_Ch05_14

rxlev (n1) = –80

pbg (n1)’ = –10

rxlev (n2) = –90

pbgt (n2)’ = –20

rxlev (s) = –70

ms_pwr_factor = 0

inner_zone_threshold(n1) = 15dB


Uplink

Pbgt(n)’ + ms_pwr_factor + inner_zone_threshold(n)+ inner_zone_margin(n) � 0

Neighbour 1 – 10 + 0 + 15 + 3 � 0

8 � 0 No

Neighbour 2 – 20 + 0 + 15 + 3 � 0

–2 � 0 Yes

Downlink

Rxlev_dl + pwr_c_d – (rxlev_ncell (n) +inner_zone_threshold(n) + inner_zone_margin(n)) � 0

Neighbour 1 –70 + 0 – (–80 + 15 + 3) � 0

pwr_c_d = 43 – 43 = 0

inner_zone_margin(n1&2) = 3dB

–8 � 0 No

Neighbour 2 –70 + 0 – (–90 +15 +3) � 0

2 � 0 Yes

interfering_nbr = 1 interfering_nbr = 1

Version 1 Rev 0Direct Inner Zone Threshold and Neighbour Report Timer



5–32

Direct Inner Zone Threshold and Neighbour Report TimerThe handover process uses two database parameters (direct_inner_zone_thresholdand neighbor_report_timer ) to determine the minimum number of measurementreports that must be received from the MS on the current channel prior to moving the MSto the inner zone. If the call is on an SDCCH, the handover process shall accelerate theprocess in an effort to reduce the number of channel changes for the MS. Using thismethod, the call may be assigned directly to a TCH in the inner zone rather than movingfirst to an outer zone TCH the then to another TCH in the inner zone. This methodallows the handover process to initiate the inner zone handover as soon as a downlinkrxlev average has been calculated if the calculated average is greater than thedirect_inner_zone_threshold . If the MS is on an SDCCH on a non–BCCH carrier,power control shall be considered in the calculation as shown below:

dl_rxlev + ((current_dl_power_level – max_tx_bts ) * 2) > direct_inner_zone_threshold

Note: The value 2 is used in the algorithm to convert absolute values into dBm.

If the above statement is TRUE, the MS qualifies for an inner zone resource.

This method is based on the assumption that if the serving cell receive level is strongenough, neighbor cells will not cause harmful interference. For all other cases, the useof the neighbor_report_timer is required.

Since this algorithm is based on neighbour information reported by the MS, the MS mustbe allowed enough time to report on interfering neighbours before moving the MS to theinner zone. This delay is defined in SACCH periods by the database elementneighbor_report_timer . The handover process counts the number of measurementreports received on a channel in the qualify_count element. Prior to receipt of thespecified number of measurement reports (i.e., qualify_count <neighbor_report_timer ), a handover to the inner zone can only be initiated if for ALL ofthe defined interfering neighbours the handover process has received hreqavemeasurements and the handover criteria is met. Once the delay has been met (i.e.,qualify_count >= neighbor_report_timer ), the handover process shall assume thatany neighbours which have not been reported by the MS are not strong enough toprohibit handover into the inner zone. As long as all reported interfering neighbours meetthe specified criteria, the handover into the inner zone shall be initiated. Whencomputing averages to determine if the call meets the inner zone use criteria, thehandover process shall compute an average using all received measurements (min of 2)for a given neighbour if less than hreqave measurements have been received.

direct_inner_zone_threshold

Valid Range 0 to 63Default = 63

neighbor_report_timer

Valid Range 0 to 255 SACCH PeriodsDefault = 10

Version 1 Rev 0 Direct Inner Zone Threshold and Neighbour Report Timer



5–33

Direct Inner Zone Threshold and Neighbour Report Timer

SYS12_Ch05_15

max_tx_bts = 43 dBm

Mobile on SDCCH and hasreceived its second dl_rxlev fromthe serving cell

dl_rxlev = –70

Current dl power level = 33 dBm

direct_inner_zone_threshold = 45 (–65dBm)

dl_rxlev + ((current_dl_power_level – max_tx_bts)*2) >direct_inner_zone_threshold

– 70 + ((5 – 0)*2) > –65

–60 > –65

For all other cases:

Before moving mobile to the innerzone, interfering neighbours musthave time to report their level

neighbor_report_timer = 10 (sacch)

qualify_count < neighbor_report_timer

Ho can only take place if all interferingn/bours reported hreqavemeasurements and HO criteria met

qualify_count � neighbor_report_timer

Any interfering n/bours not reportedexclude

�

Version 1 Rev 0Interference Based Algorithm – Handover to Outer Zone



5–34

Interference Based Algorithm – Handover to Outer ZoneThe handover process shall initiate a handover out of the inner zone if the followingalgorithm is true for any interfering neighbour:

Uplink Criteria: (Is mobile interfering with the neighbour?)

pbgt(n)’ + ms_pwr_factor + inner_zone_threshold(n) > 0

OR

Downlink Criteria: (Is the neighbour interfering with the mobile?)

rxlev_dl + pwr_c_d – rxlev_ncell(n) – inner_zone_threshold(n) < 0

Version 1 Rev 0 Interference Based Algorithm – Handover to Outer Zone



5–35

Interference Based Algorithm – Handover to Outer Zone

SYS12_Ch05_16

interfering_nbr = 1

rxlev(s)= –65

rxlev(n1) = –55pbgt(n1) = –10

rxlev(n2)= –60pbgt(n2) = –8

interfering_nbr = 1



ms_pwr_factor = 3 (in both cases)

pwr_c_d = 43 – 33 = 10

Uplink Downlink

pbgt(n)’ + ms_pwr_factor + inner_zone_threshold(n) > 0 rxlev_dl + pwr_c_d – rxlev_ncell(n)–inner_zone_threshold(n) < 0

Neighbour 1

Neighbour 2

–10 + 3 + 15 > 0

–8 + 3 + 15 > 0

Neighbour 1

Neighbour 2

– 65 + 10 – (–55) –15 < 0

– 65 + 10 – (–60) – 15 < 0

8 > 0 Yes

10 > 0 Yes

–15 < 0 Yes

–10 < 0 Yes

Version 1 Rev 0Power Control When Using Interference Algorithm



5–36

Power Control When Using Interference AlgorithmIf the call is active on a channel in the inner zone, the BSS performs an additional checkprior to ordering a power decrement. When the BSS power control algorithm determinesthat the downlink power should be decremented, a check will be performed to verify thatthe power decrement will not cause the MS to subsequently require a handover to theouter zone. The power control decrement is only allowed if the following is TRUE for ALLneighbours that have been identified as interferers:

rxlev_dl – power decrement – rxlev_ncell(n) > inner_zone_threshold(n)

If the call is active on a channel in the inner zone, and the BTS is not transmitting at themaximum power level the following equation is evaluated for ALL neighbours which havebeen identified as interferers:

rxlev_dl + power increment – rxlev_ncell(n) > inner_zone_threshold(n)

If a power increment is necessary to satisfy the above equation for ALL interferingneighbours, the power level increment is ordered. The BSS selects the minimum powerincrement that satisfies the above equation for ALL interfering neighbours. The powerincrement can only be ordered if the ordered power level remains below the maximumtransmit level.

Version 1 Rev 0 Power Control When Using Interference Algorithm



5–37

Power Control When Using Interference Algorithm

SYS12_Ch05_17

rxlev(n2) = –60 rxlev(n1) = –70

interfering_nbr = 1

rxlev(s) = – 60

1st Example 2nd Example

2 dB power 6 dB powerdecrement incrementordered ordered

Power Control Increment

rxlev_dl + power decrement – rxlev_ncell

Neighbour 1

> inner_zone_threshold(n)

–60 + 6 – (–70) >16 > 1

Neighbour 2 –60 + 6 – (–60) >6 > 1


inner_zone_threshold(n) = 15dB

Power Control Decrement

rxlev_dl – power decrement – rxlev_ncell(n)

> inner_zone_threshold(n)

Neighbour 2

– 60 – 2 – (–70) > 158 > 15 No

– 60 – 2 – (–60) > 15–2 > 15 No

Neighbour 1

interfering_nbr = 1

Version 1 Rev 0Concentric Cells – Channel Allocation Rules



5–38

Concentric Cells – Channel Allocation Rules

outer_zone usage_level

A database threshold, outer_zone_usage_level , has been introduced which allows theoperator to specify the level of traffic channel congestion which must be reached in theouter zone prior to the use of the inner zone resources. Since inner zone frequenciesmay have a tighter re–use pattern, this allows the operator to only use those frequenciesmore prone to interference if the cell is congested. If the operator chooses to use innerzone resources whenever a MS is qualified, regardless of outer usage, the databaseparameter outer_zone_usage_level can be set to 0. The tch resources in the outerzone must be greater than outer_zone_usage_level for this feature to operate.

outer_zone_usage_level

Valid Range 0 to 100 (Indicating the percentage of outer zone TCH usage)

Default = 0

Flow Control

The traffic channel flow control, congestion relief, and dynamic reconfiguration features,use the traffic channel’s usage in the outer zone ONLY to determine of the cell iscongested. Congestion relief procedures only initiate handovers for calls in the outerzone. To avoid barring of access classes prior to using the inner zone resources, theouter_zone_usage_level should be set to a lower value than both thenormal_overload_threshold and the critical_overload_threshold used by the CRMflow control feature.

intra_cell_handover_allowed

The BSS does not consider the intra_cell_handover_allowed flag when initiatinginter–zone handovers. Inter–zone handovers can be enabled or disabled separatelyusing the database parameters included with the implementation of this feature. If azone handover attempt into the inner zone fails due to congestion (that is, no inner zoneresource available) and the call qualifies for an interference handover, the call will nothandover due to interference if the intra_cell_handover_allowed flag is disabled.

Emergency call pre–emption

The BSS selects a call from the outer zone to be pre–empted for the emergency callpre–emption procedure.

Immediate Assignments

The BSS always selects an outer zone channel for an Immediate Assignment, even if atraffic channel is allocated. If there are no resources available in the outer zone, the BSSsends an Immediate Assignment Reject.

Version 1 Rev 0 Concentric Cells – Channel Allocation Rules



5–39

Concentric Cells – Channel Allocation Rules

� outer_zone_usage_level 0 to 100%

% TCH Congestion in outer zone before

handover to inner zone allowed

� Flow Control, Congestion Relief, Dynamic ChannelReconfiguration all happen in outer zone only

� Intra_cell_handover_allowed parameter irrelevant forinter–zone handovers

� option_emergency_preempt always pre–empts an outerzone call

� All Immediate Assignments in outer zone

Version 1 Rev 0Multiband Inter–cell Handover



5–40

Multiband Inter–cell HandoverMultiband inter–cell handover is an optional feature which allows a single NetworkOperator with licences in multiple frequency bands (GSM 850, GSM 900, DCS 1800,PCS 1900) to support the use of multiband mobiles. By supporting transparenthandovers between bands, Multiband inter–cell handover allows seamless operation ofthe mobile in a multiband environment. This feature includes the following:

� Multiband support at site level. (BTS site with GSM 850, GSM 900, DCS1800 andPCS 1900 in homogeneous cabinets).

� Multiband Inter–cell handovers.

� Unique Traffic Management in a multiband network using Advanced LoadManagement.

A multiband network can be either single or multi–layer. So, for example, GSM 900macro cells can operate alongside DCS 1800 macro cells. Alternatively DCS 1800 microcells could, for example, underlay GSM 900 macro cells.

All handovers between bands are inter cell and with the introduction of Single BCCHintra–cell handovers are now supported, also the normal intra–cell handovers betweenGSM and EGSM channels.

Frequency hopping is still supported as before, that is that a mobile can hop within itsown band. Hopping between bands is not supported.

Version 1 Rev 0 Multiband Inter–cell Handover



5–41

Multiband Inter–cell Handover

SYS12_Ch05_18

GSM 850

GSM 900

DCS 1800

PCS 1900

SufficientMultibandMobiles needed

Inter – CellSupported

Intra – Cellsupported withSingle BCCH for

dual Band CellsFeature

Frequency Hoppingsupported withinBands

EGSM

GSM 900 GSM 900

GSM 900

GSM 900 GSM 900

GSM 900

GSM 900 GSM 900

GSM 900

DCS 1800

DCS 1800DCS 1800

DCS 1800

DCS 1800DCS 1800

DCS 1800

DCS 1800DCS 1800

Version 1 Rev 0Multiband Inter–cell Handover



5–42

Multiband Database Parameters

In order to enable the multiband feature and all its functionality, the parametermb_preference is used.

chg_element mb_preference < * > location

< * >0= multiband handovers disabled

1= multiband handovers enabled

Once this is done, the BSS will take notice of the add_cell prompt frequency_type ,which sets the frequency band for the cell.

frequency_type (add_cell prompt)

1 or PGSM

2 or EGSM

4 or DCS 1800

8 or PCS 1900

16 or GSM 850

After a call is set up on a particular cell of course a handover may become necessary. Itis possible to specify, for each cell, the frequency band(s) of the target cell for anyhandover that is made out of that cell. This is done by the interband_ho_allowedparameter.

The system then chooses a particular band from within the interband_ho_allowedselection based on the preference set by subsequent parameters.

chg_element interband_ho_allowed < * > <cell_desc>

� � � � � � � � � ��

PGSM y X y X y X y X y X y

EGSM X y y X X y y X X y y

DCS 1800 X X X y y y y X X X X

PCS 1900 X X X X X X X y y y y

Check W23 for GSM 850 values.

Version 1 Rev 0 Multiband Inter–cell Handover



5–43


SYS12_Ch05_19

GSM 900 DCS 1800

mb_preference 1 <location>

frequency_type = 1

interband_ho_allowed 5 <cel_desc>

Version 1 Rev 0Multiband Database Parameters



5–44

Multiband Database ParametersHaving set the frequency bands to which a call in the cell can handover(interband_ho_allowed) it is possible to specify a preference for a particular one. Forexample, if interband_ho_allowed= 1 then a call could handover to a PGSM, EGSM orPCS1900 neighbour cell; it may be useful to try to hand most calls over to the PCS 1900in a multilayer system. A preference for a particular band is set by the band_preferenceparameter. It is not, however, certain that all handovers out of this cell will always go tothe preferred band, this depending upon another parameter, band_preference_mode.This parameter can cause the BSS to ignore the band_preference setting, or to take itinto account when ordering target neighbour cells for inclusion in thehandover_recognised message.

The band_preference parameter displays the frequency bands that the cell prefers touse for handovers and specifies the destination frequency band for inter–cell handovers.

Valid range1 (PGSM),2 (EGSM),4 (DCS1800),8 (PCS1900)16 (GSM850)Default value The frequency type of the cell (as set by frequency_type ).

The band_preference_mode parameter specifies the method the system uses toprogram a Multiband MS with the preferred frequency band for a given cell in the BSS.

0. The BSS attempts to hand a Multiband MS over to the strongest neighbour thatthe MS reported when a handover is required for normal radio resource reasons.

1. The BSS attempts to assign a Multiband MS to the strongest preferred bandneighbour that the MS reported at the time of SDCCH to TCH assignment. If theBSS cannot assign a preferred band TCH the BSS will not try to direct this MS tothe preferred band for the life of the current call connection. The BSS alwayshands the MS over to the strongest MS–reported neighbour when a handover isrequired for normal radio resource reasons.

2. The BSS attempts to hand a Multiband MS over to the strongest preferred bandneighbour that the MS reported when a handover is required for normal radioresource reasons. The BSS places preferred band neighbours ahead ofnon–preferred band neighbours in order to attempt to assign a channel from thepreferred band for the MS.

3. This value combines the functions of values 1 and 2.

4. The BSS continually attempts to hand a Multiband MS over to a preferred bandTCH immediately after initial assignment. The BSS will not attempt to allocate aTCH in the preferred band for this MS at the time of SDCCH–to–TCH assignment.The BSS will enter a mode of continually monitoring for qualified preferred–bandneighbours reported by the MS in order to hand the MS over. The BSS will stay inthis mode until it finds a neighbour TCH in the preferred band for the currentserving cell. Handovers for normal radio resource reasons may occur during themonitoring mode, and these handovers will be to the strongest preferred bandneighbour reported by the MS.

5. This value combines the functions of values 1, 2, and 4.

6. This value functions identically to value 5, except it is only triggered when the cellis congested.

Version 1 Rev 0 Multiband Database Parameters



5–45


sys12_ch06_18

PGSM

Serving

PGSM

StrongestOverall

PGSM

PGSM

DCS1800

Strongest

DCS 1800

DCS 1800

band_preference = 4

MS has received SDCCHand is waiting for TCH

band_preference_mode = 1

(Chooses strongest preferredband neighbour if possible, doesnot attempt to direct to preferredband during duration of call)


assignment, BSS constantly monitors fora qualified preferred band neighbour)

MS needs to handover for normalradio reasons


(Handover to strongest neighbour)


(Handover to strongest preferred band neighbour)


(Combines 1 and 2)


(Combines 1, 2 and 4)


(Combines 1, 2 and 4 but triggered forcongestion reasons)

Immediately after initial

Version 1 Rev 0Enhanced SDCCH to TCH (preferred band) Assignment



5–46

Enhanced SDCCH to TCH (preferred band) AssignmentIn the case of values 1, 3, 5 and 6, it has been found that the MS does not report onneighbour cells from other frequency bands fast enough to allow the TCH assignment tothe preferred band neighbour cell. A feature released in GSR 5.0 makes an allowancefor this. The parameter works by specifying the number of measurement reports that theRSS waits before responding to the CRM if the MS does not report a preferred bandneighbour.

sdcch_tch_band_reassign_delay

Valid Range 0 to 4 (SACCH multiframes)

Use of this parameter may cause a delay of up to two seconds.

Version 1 Rev 0 Enhanced SDCCH to TCH (preferred band) Assignment



5–47

Enhanced SDCCH to TCH (preferred band) Assignment

� The parameter works by specifying the number of measurementreports that the RSS waits before responding to the CRM if theMS has not reported a preferred band neighbour

� This is needed to allow time for the MS to report neighbour cellsfrom other frequency bands

� sdcch_tch_band_reassign_delay

Valid Range 0 to 4 (SACCH multiframes)

Use of this parameter may cause a delay of up to two seconds

Version 1 Rev 0Multiband Neighbour Measurement



5–48

Multiband Neighbour MeasurementMultiband mobiles of course produce measurement reports relating to the serving celland the best six neighbours when in dedicated mode, just as single band mobiles do.However, to ensure an equal chance of selecting each bands target cells, it is possible to“reserve” some of the six positions for neighbours in a measurement report for eachavailable band. This is done via the multiband_reporting database parameter.

multiband_reporting<element_value><location><cell_number>

Value type Integer

Valid range 0 to 3

0. Normal reporting of the six strongest neighbour cells with known and allowed NCCpart of the BSIC, irrespective of the band used.

1. Report the strongest neighbour cell, with known and allowed NCC part of BSIC, ineach of the frequency bands in the neighbour cell list, excluding the frequencyband of the serving cell. The remaining positions in the measurement report shallbe used for reporting Cells in the band of the serving Cell. Any still remainingpositions will be used to report the next strongest identified neighbours in otherbands irrespective of the band used.

2. Report the two strongest cells, with known and allowed NCC part of BSIC, in eachof the frequency bands in the neighbour cell list, excluding the frequency band ofthe serving cell. The remaining positions in the measurement report shall be usedfor reporting Cells in the band of the serving Cell. Any still remaining positions willbe used to report the next strongest identified neighbours in other bandsirrespective of the band used.

3. Report the three strongest cells, with known and allowed NCC part of BSIC, ineach of the frequency bands in the neighbour cell list, excluding the frequencyband of the serving cell. The remaining positions in the measurement report shallbe used for reporting Cells in the band of the serving Cell. Any still remainingpositions will be used to report the next strongest identified neighbours in otherbands irrespective of the band used.

Default value 0

Version 1 Rev 0 Multiband Neighbour Measurement



5–49

Multiband Neighbour Measurements

SYS12_Ch05_21

PGSM

Serving

PGSM

n6PGSM

n2

PGSM

n4

DCS1800

n5

DCS 1800

n1

DCS 1800

n3

multiband_reporting 3 <location> <cell_number>

Example:

Neighbour List

Three strongest neighbours frombands other than the serving cell

n1, n3 and n5

Then the next three neighbours from theband of the serving cell

n2, n4 and n6

Any remaining positions taken byneighbours from any band regardless ofband used

Version 1 Rev 0MSC Requirements



5–50

MSC RequirementsThe MSC can support BSS equipment from different vendor for each frequency band.This provides the operator the ability to distribute the changes required for Multibandoperation

To have a working dualband capability in the network, some MSC requirements apply.The MSC needs to have the capability to handle Classmark 3 (CM3) informationelement. CM3 information is sent by multiband mobile to MSC contains info of multibandcapabilities and the MS power classes in the different bands. The CM3 info then is storedin the MSC for the duration of the call. In case the mobile is required to perform amultiband handover, the CM3 info must be transmitted to the target BSS, which informsthe new BSS about the multiband capabilities of the mobile.

If a handover becomes necessary in a multiband environment, the network must ofcourse know the frequency band capabilities of the mobile so that a PGSM mobile is nothanded over to a DCS 1800 cell for example.

In internal handovers this discrimination is handled by the BSC as part of its normalhandover control function, but in external handovers the target BSC must be told themobile’s capabilites. Moreover, the MSC must know the mobile’s capabilities in case thisaffects its choice of BSC; in a multilayer configuration each layer could be controlled by adifferent BSC.

There are 3 GSM–defined messages for informing the network of the mobile’scapabilities

��$$��#� � ��$$��#� � ��$$��#� �

��$� !� ��

��#�) ��$$��#� $� ��

� ��

�� $&""!#%

�!(�# ��$$

��$� !� ��

��#�) ��$$��#� $� ��

� ��

�� $&""!#%

�!(�# ��$$

�) ��#! �*�%�!

�&""�� %�#) ��#'��$

�� $&""!#%

�� $&""!#%

��$$��#� � $&""!#%

��

$&""!#%

�� $&""!#%

�!(�# ��$$

Classmark 3 is the important message in multiband, but is normally only sent by themobile when interrogated by the MSC. In order to save time it is possible to sendclassmark 3 spontaneously using the parameters opposite. This will happen within 40msif the initial layer 3 message at call setup unless specified otherwise, and iscommunicated to the target BSC of an external handover in the handover requestmessage.

Version 1 Rev 0 MSC Requirements



5–51

Classmark of Mobile

� chg_element early_classmark_sending <*>0

<*> 0= disabled

1= enabled on A–interface, disabled on air interface

2= disabled on A–interface, enabled on air interface

3= enabled on A–interface and air interface

Def = 0

� chg_element early_classmark_delay <*>0

��

� Def = 0

Version 1 Rev 0ALM for EGSM Carriers



5–52

ALM for EGSM Carriers

EGSM Layer Management

In a predominantly PGSM and DCS1800 multiband network, there are problems withutilization of the EGSM frequencies. This is because of the interaction with the multibandhandover feature. The multiband handover feature uses two database parametersband_preference and band_preference_mode . If for example band_preference wasset to DCS1800 and band_preference_mode = 4, meaning on trigger of a normalhandover try to direct the call to the preferred band. Then if an EGSM capable MSestablished on a PGSM cell with EGSM capabilities, if there are idle EGSM TCHcapacity the MS will be assigned to the EGSM TCH resource. But when a handover istriggered due to RF reasons (better cell etc) the MS will be targeted to the DCS1800band, because it is the preferred band. Consequently EGSM resources are underused.The re–ordering of candidate neighbour cells when a handover is triggered dependson the MS being EGSM capable and the MS having established on a EGSM resource. Itdoes not operate with the co–incident multiband feature and cannot support externalhandovers to EGSM neighbours. It does not operate with EGSM BCCH frequencies orsupport hopping through EGSM frequencies within PGSM/EGSM cell.

Database parameters

chg_element bss_egsm_alm_allowed <*><location> (BSS only)

<*>

0 = EGSM ALM feature disabled 1 = EGSM ALM feature enabled

Neighbour Re–ordering

If we take the case of band_preference_mode = 4, the RSS process orders theneighbours into two distinct groups before reporting them to the CP process. Thesegroups are preferred band neighbours and non–preferred band neighbours. If the MS isEGSM capable and it is currently established on an EGSM TCH channel. Thenon–preferred band neighbours (in this case PGSM) will be checked to see if they haveany EGSM resources. If a neighbour does have EGSM resources, it will be placed at thehead of the list as the highest priority neighbour.

Version 1 Rev 0 ALM for EGSM Carriers



5–53

ALM for EGSM Carriers

sys12_05_alm1

Preferred

Non – Preferred

Preferred band

neighbour (DCS1800)

Non – Preferred

neighbour (PGSM)

Non – Preferred

neighbour (PGSM/EGSM )

Non – Preferred band (PGSM/EGSM)

Preferred band (DCS1800)

Non – Preferred band (PGSM)

chg_element bss_egsm_alm_allowed 1 <location>

Candidate neighbours reported from RSS

Candidate neighbours sorted by CP

Version 1 Rev 0ALM for EGSM Carriers Examples



5–54

ALM for EGSM Carriers Examples

Example 1

EGSM Capable MS Establishes on a PGSM Resource

In this case the database parameters band_preference and band_preference_modewill direct the call to the preferred band. For instance if an EGSM capable MS establisheson a PGSM TCH resource and a handover is triggered. If band_preference = DCS1800and band_preference_mode = 4, then when the next handover is triggered the MS willbe directed to the DCS1800 layer. Once on the DCS1800 layer the MS will continue to bedirected to the DCS1800 layer. If at any time the MS is handed into a PGSM/EGSM cell,if EGSM TCH resources are available, will be granted an EGSM resource.

Example 2

EGSM Capable MS Establishes on a EGSM Resource

Before this feature the MS would have been directed to a DCS1800 resource onhandover. To make better use of the EGSM resources the candidate neighbour cells aremanipulated so that any PGSM neighbour with EGSM capabilities is preferred. If thehandover to the PGSM/EGSM cell results in the MS being assigned to a PGSMresource. The BSS will revert to directing the MS to the preferred band in this caseDCS1800.

If the handover fails to the PGSM/EGSM neighbour due to no resources, then the BSSattempts to target the MS to the next neighbour which may be a PGSM/EGSM,DCS1800 or PGSM cell. Once the MS is directed to the DCS1800 layer, it will continue tobe directed to the DCS1800 layer as directed by band_preference andband_preference_mode .

Version 1 Rev 0 ALM for EGSM Carriers Examples



5–55

ALM for EGSM Carriers Example 1

If on PGSM resource will be directed by band_preference and band _preference_mode

band_preference = DCS1800 band_preference_mode = 4

If a handover occurs to a PGSM/EGSM neighbour and there are no EGSM resources

On the next handover the MS will be directed to the DCS1800 layer

PGSM/EGSM

DCS1800 DCS1800

PGSM/EGSM

EGSM MS on PGSM TCH

EGSM capable MS establishes on a PGSM TCH resource

Version 1 Rev 0ALM for EGSM Carriers Examples



5–56

Version 1 Rev 0 ALM for EGSM Carriers Examples



5–57

ALM for EGSM Carriers Example 2

Diagran Number

If on EGSM resource will not be directed by band_preference and band_preference_mode

if there are EGSM neighbours

If a handover occurs to a PGSM/EGSM neighbour and there are no EGSM resources and

the MS is assigned to a PGSM resource, then the MS will be directed to DCS1800 layer

On the next handover the MS will be directed to the DCS1800 layer and once on the

DCS1800 layer will directed to DCS1800 neighbours

If there are no PGSM/EGSM resources the BSS attempts to target the MS to the next

neighbour which could be (in order) PGSM/EGSM , DCS1800 or PGSM

PGSM/EGSM

DCS1800

DCS1800

PGSM/EGSMEGSM MS on EGSM TCH

EGSM capable MS establishes on a EGSM TCH resource

Version 1 Rev 0Coincident Multiband Handover



5–58

Coincident Multiband HandoverThis feature enables operators to install new radios in a different frequency band. Thisinstallation will turn an operator’s network into a multiband network. One obstacle to thistype of upgrade is the investment in time and money already made by the operator inoptimising the existing network. With the addition of a secondary network, with differentpropagation characteristics, this optimisation effort would have to be repeated. This candeter some operators, who want the extra capacity, from installing a multiband network.

To avoid this problem of optimising two networks, it is logical that the new secondarynetwork should complement the existing infrastructure. To achieve this, the softwaremust be configurable enough to allow the new network to use the same cell boundariesestablished by the original network. This can be done by using mobile–reportedmeasurement reports of the primary network while established on the secondarynetwork. This allows the mobile to be handled as if it were on the primary network, usingthe primary’s boundaries and minimizing propagation characteristics differences, whilstnot taking any primary network resources.

This feature is designed to complement the Multiband feature and the functionalitydescribed here is only available if that feature is enabled.

Feature objectivesThis feature has two main objectives:

� To ensure that the specific DCS 1800 cell will only unload the traffic from itscoincident GSM cell and not take traffic away from surrounding GSM cells. This isachieved by defining the DCS cell boundaries by the underlying GSM cellboundaries.

� To maintain the quality in the GSM network and only have one network to optimise.This is achieved by having the same handover boundaries between the GSM andDCS cells.

Cell Definitions

Coincident Cell

A cell that has a co–located neighbour cell whose cell boundary follows that of the saidcell, but has a different frequency type to that of the neighbour cell. The coincident cellhas only one GSM1800 neighbour, which is collocated.

Primary Cell

A cell (GSM900), that is already optimised in the network and has a co–locatedneighbour, whose cell boundary follows that boundary of the said cell. The primary cellhas a preferred band equal to the frequency type of the coincident cell (GSM1800). If nocoincident GSM1800 cell exists, then no GSM1800 neighbours are defined.

Secondary Cell

A cell, which is not optimised and has a co–located neighbour whose cell boundaryfollows the boundary of the said cell. The secondary cell has a preferred band the sameas that of its own frequency type (GSM1800). The co–located GSM1800 cell has all thesame GSM900 neighbours, as does the GSM900 cell, in addition to the co–locatedGSM900 (coincident) cell itself. In addition to the GSM900 cells, the GSM1800 cell mayhave other GSM1800 neighbours.

This feature will not affect normal multiband handovers to a preferred band.

Version 1 Rev 0 Coincident Multiband Handover



5–59

Coincident Multiband Handover

sys12_ch06_22

Secondary A

Primary CPrimary Primary B Primary D

These cells are optimised and power budget handovers can occur

B & D also C & B are neighbours of each other

All belong to the same frequency band

To increase capacity cellA and C is added to coverthe same area as cell Band C

One way neighbour

Two way neighbour

Coincident neighbour

Secondary C

Optional two wayneighbour

Version 1 Rev 0Configuring Coincident Multiband



5–60

Configuring Coincident Multibandchg_element coincident_mb <value> <location> cell=<cell_desc>

Value (valid range):

0. Coincident Multiband is disabled

1. Coincident Multiband utilises better cell detection

2. Coincident Multiband utilises coincident cell redirection

Prompts for : � GSM cell id of the host cell� coincident_offset –63 to 63� low_signal_thres 0 to 63

The BSS will use an additional offset to the power budget equation when the neighbour being used fordownlink measurements (GSM900) is not reported. If the MS is on a TCH on cell A (DCS1800) anddownlink measurements for cell B (GSM900) were not being reported, then the serving cell’smeasurements would be used in the power budget equation with addition of the offset.

When a handover condition is present to a neighbour with a coincident preferred band cell, the MSsupports multiple frequency bands and the MS reported receive level of the target cell is above thethreshold defined by this parameter; the BSS will attempt to hand the MS directly to the coincidentpreferred band cell. This functionality is only used if coincident_mb is set to 2 and is set in bothdirections (both cells have to be coincident to each other).

ExampleIn the case shown opposite, Cell A and Cell B are co–located coincident neighbours of each other.Cell B is part of the GSM900 network, while Cell A has been added and is part of the, secondary,GSM1800 network.

Assume that a mobile was using a traffic channel on cell A (DCS1800). The MS would be measuringthe strength of Cell B and Cell D (GSM900 – because they are defined in the neighbour database).When Cell A receives the measurement report from the MS, in a coincident cell, the BSS uses themeasurement level of Cell B as the downlink measurement, instead of using the downlink receivelevel of Cell A to make a decision as to whether a handover is needed. This is done because thepropagation characteristics of the two cells can vary. The BSS uses the signal strength reports of CellD from the mobile to determine whether there are any viable candidates for the needed handover(PBGT calculations). If Cell B was not decoded as a neighbour then coincident_offset is applied tothe pbgt calculation to compensate for the lower propagation characteristics of the DCS1800 Cell.

If C (DCS1800) was also a neighbour of A, the downlink receive level of cell A will be used in theserving cell power budget calculations as it is in the same frequency band.

Coincident Cell Redirection

This is the enhanced functionality of handing over to an unreported neighbour. If the BSS decides thatCell E (GSM900) is a viable candidate for handover for a MS occupying a traffic channel on Cell A(DCS1800), the BSS will detect that Cell F (DCS1800) is a coincident cell of Cell E, and will redirectthe handovers to Cell F as long as the rxlev of Cell E is detected as being above low_signal_thres .The value of low_signal _thres is set at a level which takes into account the difference in rxlevbetween the GSM900 cell and its DCS1800 co–incident neighbour.

The co–located coincident cells (GSM900 and DCS1800) must be synchronised in order to perform ahandover to an unreported neighbour; therefore the cells must be located at the same site. They alsohave to use the same BSIC to have successful communication upon handover (this requirement onlyapplies if coincident_mb is set to 2).

The cells must be synchronised because the Handover Command sent to the MS has the cell E(GSM900) cell description (the cell the MS was reporting on in the measurement reports), but the cellF (DCS1800) channel description. If the cells are not synchronised the handover will fail.

The Handover Access burst is encoded using the BSIC of the target cell – cell E (GSM900) and thuscell F must have the same value in order to successfully decode the message.

Version 1 Rev 0 Configuring Coincident Multiband



5–61

Configuring Coincident Multiband

Cell

PGSM

ECell

PGSM

E Cell

PGSM

BCell

PGSM

B Cell

PGSM

DCell

PGSM

D

Cell

DCS1800

ACell

DCS1800

A Cell

DCS1800

CCell

DCS1800

CCell

DCS1800

FCell

DCS1800

FCell

DCS1800

F

coincident_mb =2 for both cellsE and F

BSIC same for E and F

Sync handovers enabledbetween cells F and E

band_preference =4 for cell E

PBGT handover to cell F whenmeasured rxlev abovelow_signal_thres

coincident_mb = 1 for cells A,C,B and D

Or they are not and coincident_offsetused to compensate for the lowersignal strength of the DCS 1800 cell.This offset is added to the ho_margin

Optionally A and C can be neighbours

Version 1 Rev 0Coincident Multiband External Neighbour Enhancements



5–62

Coincident Multiband External Neighbour EnhancementsPrior to GSR6 problems were encountered when an external handover occurred betweencells with coincident neighbours with coincident_mb = 2. This was because the criteriafor a seamless redirected handover to the secondary DCS1800 cell is based upon therxlev of the primary GSM900 neighbour cell being above low_signal_thres . In the caseof an external neighbour the result of this calculation would never be used as it is madein the source BSC. Hence mobiles were being redirected to the secondary DCS1800 cellincorrectly and causing bad quality in the network. The solution is to offer a newcoincident multiband option of 3.

Operation

chg_element coincident_mb <value> <location> cell=<cell_desc>

value = 3 Internal cells uses coincident_mb = 2 External cells uses coincident_mb = 1

For the example on the opposite page we have a coincident cells on the border of twoBSCs A and B. For these cells we have set coincident_mb = 3. If a handover from asecondary DCS1800 cell occurs internally then the redirected handover can occur in thenormal way by coincident_mb = 2 and coincident_offset as the calculation oflow_signal_thres can be made within the same BSC and the correct decision can bemade whether to redirect or not. However if the handover from a secondary DCS1800cell is external then it uses coincident_mb = 1 so better cell detection is used basedupon coincident_offset . If however the actual cell size was the same for the GSM900and DCS1800 coincident cells then calculation of low_signal_thres is no longer ofconsequence and the border cells can be set at coincident_mb = 2.

Version 1 Rev 0 Coincident Multiband External Neighbour Enhancements



5–63

Coincident Multiband External Neighbour Enhancements

SYS03_ch05_coinenh

Cell

PGSM

ECell

PGSM

E Cell

PGSM

BCell

PGSM

B Cell

PGSM

DCell

PGSM

D

Cell

DCS1800

ACell

DCS1800

A Cell

DCS1800

CCell

DCS1800

CCell

DCS1800

FCell

DCS1800

FCell

DCS1800

F

coincident_mb =3 for cells F and E

BSIC same for E and F + Sync handovers

coincident_mb = 3 for cells A and B

BSIC same for A and B + Sync handovers

coincident_mb = 2 for cells C and D

BSIC same for C and D + Sync handovers

BSC A BSC B

For internal handovers uses same ascoincident_mb = 2

For external neighbours usescoincident_mb = 1

Version 1 Rev 0Single BCCH for Dual Band Cells



5–64

Single BCCH for Dual Band CellsThis is a feature developed in GSR 5 software release. GSM specifications allow the useof a common BCCH for different bands of operation when resources across all bands areco–located and synchronised. With this feature it is possible for carriers within a cell to beconfigured in different frequency bands.

Feature Overview

Restricted Features

The following restricted features need to be enabled

Dual Band Cells

Concentric Cells

Multiband Handovers

Homogeneous Cabinet (Cabinets at a site can be of different frequency types)

Heterogeneous Cabinet (Cabinets are able to support multiple frequency types and isrequired for combined cabinet configurations only)

Frequency Hopping

Because Frequency Hopping between different bands in not allowed per GSMspecifications, the dual band cells feature only supports frequency hopping that aredefined to contain frequencies from a single frequency band. In a dual band cell thehopping systems may contain either primary or secondary band frequencies, but not acombination of both.

Version 1 Rev 0 Single BCCH for Dual Band Cells



5–65


� Restricted Features

� Dual Band Cells

� Concentric Cells

� Multiband Handovers

� Homogenous Cabinet

� Heterogenous Cabinet

� Frequency Hopping

Version 1 Rev 0Single BCCH for Dual Band Cells



5–66


Feature Overview (Continued)

The single BCCH for dual band cells provides the capability to configure and managecells with carriers from different frequency bands by using the concentric cellsconfiguration.

� Primary band carriers are configured in the outer zone, to provide total cellcoverage

� To be consistent with the concentric cells feature the BCCH and SDCCHs must bein the primary band, along with any other non–BCCH carriers of the same band

� Secondary band carriers are configured in the inner zone and these contain theremaining non–BCCH carriers. In effect the inner zone coverage could be thesame as the outer zone

� For this feature to operate efficiently the operator would need a subscriber basepopulated with a sufficient number of multiband capable mobiles

� The feature benefits operators by providing a convenient way of expanding systemcapacity by utilizing frequencies from the secondary band provided a sufficientmultiband capable subscriber population exists

� This strategy enables system capacity to be increased without modifying thefrequency plan.

� Or, the neighbour list

Version 1 Rev 0 Single BCCH for Dual Band Cells



5–67


SYS12_Ch05_24

D

Primary Band

Outer Zone

Contains BCCH carrier, SDCCHand any optional non – BCCHcarriers

Secondary Band

Inner Zone

Remaining non –BCCH carriers

Sufficient number ofmultiband mobiles

System Expansion

No need to modifyfrequency plan

No need to modifyassociatedneighbour lists

Version 1 Rev 0Frequency Types



5–68

Frequency TypesTwo different frequency types at cell level can be configured, these can be a combinationof PGSM, EGSM, DCS1800 or GSM850. Any of these bands can be assigned as theprimary band for the cell.

Primary Band

The primary band is set using frequency_type , to add or change a frequency type, addcell or change cell element is used.

Secondary band

The secondary band is set using secondary_freq_type database parameter. This isprompted after the inner zone algorithm has been set to 3 to enable the dual band cellsfeature, or can be modified using the change cell element command.

Dependancies

� If the primary cell frequency type is DCS1800 the secondary frequency type caneither be PGSM, EGSM or GSM850

� If the primary cell frequency type is PGSM or EGSM the secondary frequency typemust be DCS1800 or GSM850

� Cell and cabinet frequency types must be allowed at the BSS as per thefrequency_types_allowed command

Version 1 Rev 0 Frequency Types



5–69

Frequency Types

SYS12_Ch05_25

Primary Band

Secondary Band

PGSM

DCS1800

EGSM

DCS1800

PGSMDCS1800

EGSMDCS1800

Primary band set by frequency_type

Secondary band set by:

secondary_freq_type

Range 1 PGSM

2 EGSM

4 DCS1800

16 GSM850

frequency_type = DCS1800

secondary_freq_type = PGSM

or EGSM

frequency_types_allowed

frequency_type = PGSM or EGSM

secondary_freq_type = DCS1800

Version 1 Rev 0Modification Overview



5–70

Modification Overview

inner_zone_alg <value>cell=<cell_desc>

The procedure to establish a dual band cell configuration begins with modifying the innerzone algorithm element for the new dual band cell. This is accomplished by using a valueof 3.

Once this value is entered the following secondary band parameters are prompted:

� Frequency Type of the secondary band

� BTS maximum transmit power level

� MS maximum transmit power level

� Handover power level

� Handover hysteresis

� Downlink receive level threshold

� Uplink receive level threshold

� Dual band offset

� Power budget mode

� These parameters are explained fully later.

Equipping DRI and RTF groups

With dual band cells it is necessary to equip DRI and RTF groups per cell since thefrequency type of the RTF must match the radio equipment tied to the DRI. There mustbe different DRI and RTF groups associated with the primary band and the secondaryband of a dual band cell. Secondary band carriers must be equipped as inner zonecarriers.

Outer zone usage

At this point the operator must indicate the percentage of outer zone traffic channels thatneed to be in use prior to the assignment of secondary band channels. This is set byouter_zone_usage_level database parameter.

Version 1 Rev 0 Modification Overview



5–71

Modification Overview

� inner_zone_alg <value> cell = <cell_desc>

� Where value 3 = dual band cell in use

– Frequency type of the secondary band

– BTS maximum transmit power level

– MS maximum transmit power level

– Handover power level

– Handover hysteresis

– Downlink receive level threshold

– Uplink receive level threshold

– Dual band offset

– Power budget mode

� DRIs and RTFs for the secondary band must be equipped

– outer_zone_usage_level

Version 1 Rev 0Dual band Inner Zone use Algorithms



5–72

Dual band Inner Zone use AlgorithmsThe dual band inner zone use algorithm differs from the power based use algorithm in anumber of ways. Rather than defining the maximum transmit power for the inner zone ona per carrier basis the inner zone use algorithm defines the maximum transmit power asone value applied to all secondary band carriers.

Propagation Differences

In order to account for propagation differences between bands and allow secondary bandcarriers to provide total cell coverage, the inner zone use algorithm allows the maximumtransmit power level of secondary band carriers to exceed the maximum transmit powerlevel of the primary band.

Power losses

Unlike the power based algorithm which uses the power level at the radio as a referencepoint and assumes a consistent degradation of the signal for all carriers in the cell fromthat point on , the inner zone use algorithm must consider other factors when comparingsignal strengths from different frequency bands to accurately determine whether a mobilecan be served by a secondary band channel. These factors are:

� Due to different level of combining the loss of power between the radio unit and thetop of the antenna may not be consistent across all radio units within the cell. Thepower difference is calculated by subtracting the secondary band power loss fromthe primary band power loss.

� Due to the radio frequency propagation being weaker at 1800 MHz than at 900MHz, propagation loss over the air interface has got to be taken into consideration.

� These factors are accounted for in the database parameter

dual_band_offset = <*>

Range = –63 to 63

Version 1 Rev 0 Dual band Inner Zone use Algorithms



5–73

Dual band Inner Zone use Algorithms

SYS12_Ch05_26

Primary Band

Secondary Band

Max transmit power same for all secondary

Max transmit power of secondarycan exceed mas trasmit power ofprimary

carriers

Max powersecondary = 43dBm

Max powerprimary = 37dBm

Radio power level changes

– Power loss from radioto top of antenna

– Propagation loss

Loss of powerbetween radioand top ofantenna

Power D = primary band power loss –

secondary band power loss

RF propagation isweaker at1800MHz than900MHz

dual_band_offset = Power D + Propagation D

Range = –63 to 63

Version 1 Rev 0Dual Band Inner Zone Algorithms



5–74

Dual Band Inner Zone AlgorithmsThis section concerns the use of dual band inner zone algorithms.

� Basically inter zone management is provided by the concentric cells feature.

� It uses the power based use algorithm which manages traffic between zones usingalgorithms based on uplink and downlink receive levels.

� Also the operator is able to manually set preferences by using the databaseelement, outer_zone_usage_level . If it is set to 0, channels in the inner zone areused whenever a mobile is qualified to use those resources. If set from 1 to 100inner zone resources are allocated only when a mobile is qualified and at least thespecified percentage of outer zone traffic channels are in use.

� Traffic between frequency bands of different cells is currently managed by themultiband feature. To achieve a satisfactory algorithm for inter–zone trafficmanagement, with dual band cells, the concentric cells power based use algorithmis enhanced with multiband features inter–band traffic management shifted frominter–cell to intra–cell level.

Version 1 Rev 0 Dual Band Inner Zone Algorithms



5–75

Dual Band Inner Zone Use Algorithms

SYS12_Ch05_27

Primary Band

Secondary Band

Concentric Cells

Uplink and downlink receive levels

outer_zone_usage_level = 0 to 100

Enhanced multiband feature

Version 1 Rev 0Dual Band Inner Zone Use Algorithms



5–76

Dual Band Inner Zone Use AlgorithmsIn comparing the receive levels of the outer zone to the inner zone threshold, the innerzone use algorithm must adjust for values being from two different frequency bands andconvert the primary band receive levels to an estimated value for the secondary band.This is done using the dual band offset parameter.

RXLEVINNER = RXLEVOUTER + dual_band_offset

This offset is applied to both uplink and downlink receive levels

Algorithms

The calculated receive level inner value is then used in the dual band inner zonealgorithm for both uplink and downlink

RXLEV_DL INNER > rxlev_dl_zone + zone_ho_hyst + (bts_txpwr –bts_txpwr_max_inner)

RXLEV_UL INNER > rxlev_ul_zone + zone_ho_hyst + (ms_txpwr –min(ms_txpwr_max_inner,P)

Within this algorithm are database parameters that are set per cell after theinner_zone_alg = 3 (dual band use)

rxlev_dl/ul_zone = <*> * = Range 0 to 63

zone_ho_hysteresis = <*> * = Range –63 to 63

bts_txpwr_max_inner = <*> * = Range as defined for max_tx_bts (0 to 21)

ms_txpwr_max_inner = <*> * = Range as defined for max_tx_ms (5 to 39 PGSMand EGSM 0 to 36 DCS 1800)

P = maximum capability of the mobile in the inner zone frequency band.

Version 1 Rev 0 Dual Band Inner Zone Use Algorithms



5–77

Dual Band inner Zone Use Algorithms

� RXLEVINNER = RXLEVOUTER + dual_band_offset

� (RXLEV_DLINNER > rxlev_dl_zone + zone_ho_hyst + (bts_txpwr – bts_txpwr_max_inner )

� (RXLEV_ULINNER > rxlev_ul_zone + zone_ho_hyst + (ms_txpwr – min(ms_txpwr_max_inner,P )

� rxlev_dl/ul_zone Range 0 to 63

� zone_ho_hysteresis Range –63 to 63

� bts_txpwr_max_inner Range as defined for max_tx_bts (0 to 21)

� ms_txpwr_max_inner Range as defined for max_tx_ms (5 to 39 PGSM and EGSM 0 to 36 DCS1800)

� P is the maximum power of MS in inner zone

Version 1 Rev 0Dual Band Inner Zone Use Algorithms



5–78

Dual Band Inner Zone Use AlgorithmsThis page deals with the algorithms necessary to handover calls from the secondaryband to either the primary band or a qualified neighbour. The algorithms for uplink anddownlink depend on whether BTS and mobile power control is switched on or off.

BTS Power Control on

rxlev_dl < rxlev_dl_zone and bts_txpwr = bts_txpwr_max_inner

Receive level downlink is less than the receive level threshold and the BTS is at fullpower

BTS Power Control off

rxlev_dl < rxlev_dl_zone

Receive level downlink is less than the receive level threshold

MS Power Control on

rxlev_ul < rxlev_ul_zone and ms_txpwr = min(ms_txpwr_max_inner,P)

Receive level uplink is less than the receive level threshold and the mobile is at full power

MS Power Control off

rxlev_ul < rxlev_ul_zone

Handovers to n/bours

The neighbour cells are assessed first to see if they are suitable cells to handover too

pbgt(n) > ho_margin

If any neighbour qualifies, a handover is initiated otherwise the mobile is moved to theouter zone.

Version 1 Rev 0 Dual Band Inner Zone Use Algorithms



5–79

Dual Band Inner Zone Use Algorithms

� rxlev_dl < rxlev_dl_zone and bts_txpwr = bts_txpwr_max_inner

� rxlev_dl < rxlev_dl_zone

� rxlev_ul < rxlev_ul_zone & ms_txpwr = min(ms_txpwr_max_inner,P )

� rxlev_ul < rxlev_ul_zone

� pbgt(n) > ho_margin if neighbour qualifies inter–cell handover

� If no neighbour qualifies handover MS to outer zone

Version 1 Rev 0Enabling the Dual Band Feature



5–80

Enabling the Dual Band FeatureA resource from either the secondary or primary band of a dual band cell will be allocatedfor assignments or handovers provided the necessary criteria is met. These include thepreviously discussed restricted features that need to be enabled and the need for theinner zone algorithm to be set to 3. There are further criteria for enabling the dual bandfeature.

Multiband

� The database parameter multiband preference has to be set to 1 to enable themultiband feature.

mb_preference <value> <location>

Valid Range = 0 multiband feature disabled

1 multiband feature enabled

� The database feature coincident multiband must be set to disabled in order tochange inner zone algorithm to indicate dual band cells. This is because dualband and coincident multiband cannot be configured simultaneously.

coincident_mb = 0 (disabled)

� The mobile must support the frequency band of the inner zone.

� The database parameter band preference mode must be set to either 1,3,5 or 6

band_preference_mode = 1, 3, 5 or 6

� The parameter interband_ho_allowed defines the frequency types of the BCCHcarrier of target cells that are allowed for intercell handover. If the target cell is adual band cell the actual channel assigned by the target cell may be of a frequencytype not specified by interband_ho_allowed as long as the mobile supports thatfrequency type.

chg_element interband_ho_allowed <value> <location> cell=<cell_desc>

Valid range1 to 11 (PGSM, EGSM, DCS1800 and PCS1900)

16 to 27 (The above plus GSM850)

� The percentage of outer zone traffic channel usage meets or exceeds the outerzone usage level.

Version 1 Rev 0 Enabling the Dual Band Feature



5–81

Enabling the Dual Band Feature

SYS12_Ch05_28

Primary Band

Secondary Band

mb_preference <value> <location>

Valid Range = 0 multiband feature disabled1 multiband feature enabled

coincident_ mb set to 0 or disabled

Multibandmobile

band_preference_mode = 1,3,5or 6

interband _ho_allowed

Inner zone signalstrength criteria met

TCH usage exceeds outer_zone_usage_level

Version 1 Rev 0Handover and Power Control



5–82

Handover and Power ControlWith the dual band feature it is necessary to perform intra cell handovers both within thesecondary and primary bands as well as between the secondary and primary bands of adual band cell. The BSS performs power level conversions during intra cell channelchanges between channels of different frequency bands.

It is also necessary to perform inter–cell handovers from the secondary and primarybands of a dual band cell as well as to the secondary and primary bands of a dual bandcell.

The power budget equation determines the need for an inter–cell handover by essentiallycomparing the serving cell BCCH signal strength to the neighbour cell BCCH signalstrength. This means the signal strength in a dual band cell must come from the primaryzone. When the call is in the secondary zone, the signal strength reported by the mobilecannot be used in the power budget equation, because frequencies in the secondaryband have a different propagation than frequencies in the primary band.

Version 1 Rev 0 Handover and Power Control



5–83

Handover and Power Control

SYS12_Ch05_29

PrimaryBand

SecondaryBand

PrimaryBand

Band

SecondaryBand

Neighbour cellBCCH signalstrength

Serving cellBCCHsignalstrength

Serving cellBCCHsignalstrength

If call is in thesecondary zone,signal strengthreported bymobile cannot beused in pbgtequation

SecondaryBand

Primary

Version 1 Rev 0Power Budget Calculation



5–84


Power Budget Mode

There are two ways to obtain the primary zone signal strength, selectable via thepbgt_mode data base element.

If pdgt_mode = 1

If the mobile is assigned to a resource on the secondary band, the mobile will use theserving channel measurements and then subtract the dual_band_offset . This estimatedvalue is then inserted into the power budget equation.

If the pbgt_mode = 0

The serving cell BCCH is included in the ba_sacch neighbour cell list of the serving cell.The mobile will then report the serving cell signal strength for the primary band, whichcan be used in the calculation of power budget for neighbours with the same frequencyband. The actual number of neighbour frequencies that can be reported on is reduced byone, also the number of true neighbours that the MS can report on is reduced from six tofive. If pbgt_mode = 0 then the server is auto equipped as a neighbour.

Handover Power Level Inner

The database parameter ho_pwr_level_inner specifies the handover power level for theinner zone. It is set when the inner_zone_alg is set to dual band cell, the BSS thenprompts for the value to be entered. This allows secondary and primary bands to havedifferent handover power levels, rather than having one value for the entire cell.

Transmit Power Capability

Before development of this feature, transmit power capability could only be modifiedwhen the frequency type of the cell is set to DCS 1800 or PCS 1900. The tx_pwr_cap isused to indicate that the carrier units are capable of high power. The dual band cellsfeature has modified this parameter so that it can be set when the primary, outer zonefrequency type of the cell is PGSM, EGSM, DCS 1800 or GSM850.

Dependancies

This parameter is valid only if the RCUs, (D)RCUs, SCUs or TCUs at the site areinactive.The system does not accept this parameter if the associated DRIs are unlocked.

Version 1 Rev 0 Power Budget Calculation



5–85


� pbgt_mode = 1

� RXLEV_DLEST_BCCH = RXLEVINNER_ZONE – dual_band_offset

� RXLEV_DLEST_BCCH is then used in power budget equation

� pbgt_mode = 0

� BCCH frequency of serving cells is added to the BA SACCH neighbour cell list ofserving cell

� Serving cell BCCH takes the place of an actual neighbour

� Serving cell is auto equipped as a neighbour

� ho_pwr_level_inner Range from 2 to 19,0 to 15 based on the phase and class of the mobile

� tx_power_cap Used to indicate that the carrier units are capable of high power

Version 1 Rev 0EGSM Layer Management Within a Dualband Cell



5–86

EGSM Layer Management Within a Dualband CellDualband cells allow DCS1800 secondary band carriers to be considered as a preferredband neighbour. But before the secondary band of he dualband cell can be considered itmust first qualify, by passing some entry criteria calculated on the downlink rxlev of theprimary band BCCH reported. If the secondary band of the dualband cell does qualify it issorted as a preferred band neighbour. In the modified candidate list shown opposite thenon–preferred band neighbour BCCH (PGSM/EGSM) cells with DCS1800 secondaryband resources appear in the list twice. Once as a preferred band resource and once asa non–preferred band resource. If the MS is EGSM capable and is currently establishedon an SDCCH, band_preference_mode is set to 1, 3 or 5 and there are free EGSMresources in the current cell. The band_preference_mode which would normallyhandover the call to the strongest preferred band neighbour cell will be ignored in thiscase, and a free EGSM resource will be allocated to the call.

To implement the EGSM layer management feature call processing ignores any zonehandovers directed to the DCS1800 frequency band when a EGSM capable MS is on anEGSM TCH in the primary band.If an intercell handover is triggered and the EGSMcapable MS is on an EGSM TCH resource in a dualband cell. The MS is directed to thenext available cell with an EGSM resource, whether it be a single band cell or a primaryband resource within a dualband cell. If this handover cannot take place, for examplecongestion reasons. The MS will be targeted to the next neighbour in the neighbour list,the neighbour maybe a single band DCS1800 cell, a dualband cell with DCS1800resources or a single band PGSM cell, as directed by band_preference . When anEGSM capable MS establishes on a PGSM TCH resource in a dualband cell and a zonehandover is triggered to direct the MS to the secondary band within the cell. The zonehandover will be processed and the MS shall be handed into the secondary band(DCS1800).

Version 1 Rev 0 EGSM Layer Management Within a Dualband Cell



5–87

EGSM Layer Management Within a Dualband Cell

Preferred band

Non–preferred band

Non–preferred band (PGSM/EGSM)

Non–preferred band (PGSM)

chg_element bss_egsm_alm_allowed 1 <site number>

Candidate neighbours reported from RSS

Candidate neighbours sorted by CP

Preferred bandneighbour (DCS1800)

Non–preferred bandneighbour (PGSM)

Non–preferred bandneighbour (PGSM/EGSM)

Non–preferred bandneighbour (PGSM/EGSM)with secondary DCS1800Non–preferred bandneighbour (PGSM) withsecondary DCS1800

Non–preferred band neighbour(PGSM/EGSM) with secondary DCS1800

Preferred band (DCS1800)

Version 1 Rev 0Extended Range Cell



5–88

Extended Range CellMotorola supports a software feature called ‘Extended Range Cell’ or ERC that allowsmobiles to use a cell beyond the GSM specified 35 kilometre limit.

At distances greater than 35 Km the propagation delay exceeds the standard GSMtiming advance of 63 bit periods or 233us. This timing advance is sufficient for thetwo–way propagation delay between the BTS and the MS to be overcome.

From distances over 35km, the MS’s transmitted signal will begin to arrive in the followingtimeslot, corrupting the data being processed in both timeslots. With the ERC featureenabled, the BTS expands its receive window to cover both the MS allocated timeslotand the following timeslot. This gives an effective 156 extra bit periods for thepropagation delay which increases the maximum cell radius to 121km.

In simple terms, it is necessary to use two normal timeslots to form a single extendedrange timeslot. Using two timeslots allows the BTS to handle additional propagationdelay from the mobile.

The actual value of timing advance given to the MS can still only go up to 63 bit periods,but as the MS’s transmit burst can be late by a whole timeslot at the BTS and still bedecoded correctly.

The extended range cell feature is supported by the SCU, TCU and CTU families ofradio.

Version 1 Rev 0 Extended Range Cell



5–89

Extended Range Cell

SYS12_Ch05_30

2 3 4 5 6 7 0 1 21

2 3 4 5 6 7 0 1 21 2

TxBTS

RxMS

7 0 1 2 3 4 5 6 76

7 0 1 2 3 4 5 6 76

TxMS

RxBTS

Propagation Delay

3 timeslot offset

Propagation Delay

To prevent the burst from moving from its timeslot into a neighbouring timeslot a timing advanceis introduced to send the burst earlier therefore overcoming the propogation delay

Extended range allows the complete use of the next timeslot, hence a further 156 bits, whichtogether with the 63 bits from the primary timeslot gives a radius of 121 km

The maximum timing advance for a normal range timeslot is 63 bit or a propogation distance of35 km radius anymore than this and it runs into the next timeslot.

�

�

�

Version 1 Rev 0Timeslot Allocation



5–90

Timeslot AllocationIn an extended range cell, all BCCH and SDCCH control channels are allocated dualtimeslot channels.

This allows the cell signalling to cover mobiles within the 35–Km limit and the extendedcoverage range (up to 121km).

When a mobile originates, it is assigned either a single timeslot or dual timeslot channel,based on the timing advance information. Mobiles can also move between normal rangeareas and extended range areas based on timing advance information reported.

It is recommended that combined control channels be configured for two carrier cells.

If non–combined control channels are used the 8 SDCCH’s placed on the second carrierwould also need to be allocated an extended range cell timeslot. This will reduce thecapacity of the cell by either one extended range cell timeslot or two normal rangetimeslots.

It can be assumed that with some extended timeslots configured, that the signallingrequirements will be reduced from that of a two carrier cell with all normal timeslotconfigured. However, this is not to say that it cannot be configured for non–combinedwhere conditions dictate.

Version 1 Rev 0 Timeslot Allocation



5–91

Timeslot Allocation

SYS12_Ch05_31

Extended TCH Extended TCH

CONTROLCONTROL Extended TCH Extended TCH TCH

TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7

TS0 TS1 TS2 TS3

TCH TCHTCH TCH

TS7TS4 TS5 TS6

BCCH

Non –BCCH

Each carrier can have between 0 and 4 extended range timeslots

All BCCH, CCCH or SDCCH must be extended range timeslots

TCH

�

�

Version 1 Rev 0Extended Range Cell parameters



5–92

Extended Range Cell parametersThe extended range cell feature is enabled using the parameter ext_range_cell .

The range of the extended range cell is dictated by the timing advance applied to it. Theparameter ms_max_range has an increased range, from 63 to 219.

Each of these timing advances equates to 550m.

If the extended range cell feature is activated, then the number of timeslots per carrierassigned to extended range use is assigned within the equip rtf command.

A maximum of 4 extended range timeslots can be assigned per carrier, each consistingof a pair of normal range timeslots.

A maximum of 20 SDCCH’s are allowed in the extended range cell feature. These mustall reside on the BCCH carrier.

This configuration will be spaced over 3 timeslots utilizing a combined multiframe.

The priority of extended range cell carriers can be altered by use of the add_neighborcommand. Carriers are classified as normal or extended range.

Version 1 Rev 0 Extended Range Cell parameters



5–93

Extended Range Cell Parameters

chg_cell_element ext range_cell = <*><cell decription>

<*> 0 = extended range disabled

1 = extended range enabled

chg_element ms_max_range = <*><location>cell =<cell desc>

<*> = 0 to 63 Normal range cell

= 0 to 219 Extended range cell

equip <site> RTF

.

.

enter the number of extended range timeslots allowed: 0 to 4

chg_element max_number_of_sdcchs = <*><location>cell=<cell desc>

<*>=maximum of 20 for extended range cell

add_neighbour <source><target><placement><list_type>

.

Enter the range of the neighbour cell: normal or extended.

Version 1 Rev 0Extended Range Handovers



5–94

Extended Range Handovers

Intra–cell Handovers

If the mobile is on an extended range timeslot, but its timing advance indicates that itwithin 35Km of the BTS i.e. < 63 bits. Then an intracell handover occurs to a normalrange timeslot to save resources for distant mobiles. The opposite happens when themobile is on a normal range timeslot and moves beyond 35Km of the BTS i.e. > 63.

Inter–cell Handovers

When a handover occurs from a normal range cell to an extended range cell, the targetcell (which does not know the mobile timing advance) will always assume that theincoming call requires an extended range timeslot, so that no matter where the incomingmobile is located, (within range of the extended range cell) the call will always survive.Therefore the target cell will always allocate an extended range timeslot if possible.

When the handover actually takes place, the target cell will examine the mobiles timingadvance and if it is in fact below 63 bit periods (I.e. within range for a normal range cell) itwill handover to a normal range timeslot.

To assist with this procedure, the serving cell prioritises the neighbours. Firstly, the timingadvance is compared to a threshold.

Prior to GSR 5.0 the threshold was 50. With GSR 5.0 it is now possible to set thethreshold with the parameter erc_ta_priority . The value can be set between 0 and 63.

If the timing advance is above the threshold, the extended range neighbours are placedat the top of the list of handover candidates.

If the timing advance is below the threshold, the extended range neighbours are placedat the end of the list of handover candidates.

• erc_ta_priority = <*> * = 0 to 63

Version 1 Rev 0 Extended Range Handovers



5–95

Extended Range Handovers

SYS12_Ch05_34

Normal range CellExtended Range Cell

Timing Advance < Threshold ERC neighbours at the end of neighbour list

Timing Advance > Threshold ERC neighbours top of neighbour list

erc_ta_priority = <*> * = 0 to 63

Timing Advance compared to a Threshold

Serving Cell Prioritises Neighbours

Version 1 Rev 0RF Planning Guidelines



5–96

RF Planning GuidelinesMost of the GSM900 mobiles in use in networks around the world are Class 4. Thesegive an output power of 2 Watts. However, Class 2 mobiles are still manufactured whichgive an output of 8 Watts and are able to transmit further.

For planning purposes the Class 4 (2W) mobile should be used for consistency

The sensitivity of the MS is fixed by the manufacturer and is primarily designed for theGSM specification of a 35km cell.

The BTS can, however, be optimised by increasing transmit power. Sensitivity can alsobe increased through the use of low noise masthead amplifiers.

Another consideration is that the primary propagation method of GSM is Line of Sight(LOS). As such the height of the transmitting / receiving antenna is vital.

The simple formula listed in the example shows the minimum height required to reach aspecific distance.

Version 1 Rev 0 RF Planning Guidelines



5–97

RF Planning Guidelines

SYS12_Ch05_32

Example

540M + 46M

86.607 km

d = (2rh)

h = height of the antenna including height above sea level

Where r = radius of the Earth = 6.4 x 10 m

d = (2 x 6.4 x 106 x 586)

D = 86.607 km

1

2

_

1

2

_

6

Version 1 Rev 0Maximizing Output Power



5–98

Maximizing Output PowerTo maximise the output power of the Base Station, single carrier cells can be used. Thiswill avoid the combination losses of multiple carrier cells.

This means that the output power at the top of the cabinet could be set to 40 watts(900MHz), giving an increase in signal strength of 3 dB. However, this will limit thecapacity handling ability of the cells. For cells where additional carriers are required, aircombining can be implemented so that the combination losses are minimised.

To maximise transmit and receive powers, high gain directional antennas are should beimplemented with a minimum of 16dBi gain, however the exact specifications will dependon the specific application. The antennas should also be mounted as high as is practical.Obviously, the higher the antenna is the larger the propagation distance.

Note: Where possible sites should be located on top of hills, etc to gain the height abovethe average surrounding terrain. This allows for large effective antenna height withoutthe need for high towers. The horizon distance should also be taken into account whendeciding the antenna height.

Version 1 Rev 0 Maximizing Output Power



5–99

Maximizing Output PowerSingle carrier cells

� Avoid the combination losses of multiple carrier cells.

Multiple carrier cells

� Air combining to minimize combination losses.

Base Station Antennas

� High gain directional antennas

� Wherever possible antennas should be positioned on high ground

Version 1 Rev 0Maximizing Receiver Sensitivity



5–100

Maximizing Receiver SensitivityNothing can be done to improve the sensitivity of the mobile phone as it is fixed to thespecifications of each manufacturer. Therefore the design figure to be used in the linkbudget calculations is –102dBm ,as per ETSI specifications.

Optimizing the receive path will improve the sensitivity. The exact figure will depend onthe specifications of the amplifier used.

Motorola 900 and 1800 radios are already designed to exceed the ETSI specifications forBTS sensitivity. In addition to this, the implementation of Low Noise Mast Head Amplifierswill add significantly to the effectiveness of the cell.

Low noise amplifiers can give gains of up to 12dB in the uplink.

Version 1 Rev 0 Maximizing Receiver Sensitivity



5–101

Maximizing Receiver Sensitivity

SYS12_Ch05_33

MS Sensitivity fixed

Link budget design specification of –102 dBm

Low Noise Mast Head Amplifiers

Gains of up to 12dB in the uplink

MHA

Bias – Tee (internal to MHA)

BTS DC voltage

RF feeder

�

�

Version 1 Rev 0Maximizing Receiver Sensitivity



5–102



6–1

Chapter 6

Adaptive Multi–Rate and Half–Rate

Version 1 Rev 0



6–2

Version 1 Rev 0 Adaptive Multi–Rate and Half Rate



6–1

Adaptive Multi–Rate and Half Rate

Objectives

� Discuss Half Rate

� Discuss Adaptive Multi–Rate.

� Consider AMR Half and Full Rate

� Consider AMR Half and Full Rate Link Adaptation

� Discuss MS Monitor Functionality

� Discuss Handover and Power Control Parameters for AMR

Version 1 Rev 0Half Rate



6–2

Half RateThe GSM Half Rate feature offers enhanced capacity over the air interface,corresponding to the proportion of mobiles within a coverage area that supports HalfRate. An air timeslot is split into two sub–channels, each containing a half rate channel.Speech quality is considered inferior to other speech codecs but has a high penetrationlevel (of GSM HR capable mobiles) due to its early introduction into the standards. Dueto these large penetration levels it is considered a viable option for high density areas.

A GSM HR call can fit within an 8kbps timeslot (an Ater channel) on the terrestrialresource from the BSC to the RXCDR, rather than the 16kbps timeslot required for FRcalls. If a percentage of the active calls can be assumed to be HR, then efficiencies canbe gained by reducing the number of terrestrial resources between the BSC and RXCDR.This is possible only if the BSC can dynamically allocate a timeslot to a CIC on an8kbps/16kbps basis. This dynamic allocation is performed across a trunked interfacebetween the BSC and a remote transcoder (RXCDR). This interface is called the Aterinterface. The dynamic allocation is an enhancement to the existing Auto Connect modefeature, referred to as ”Enhanced Auto Connect mode”. Enhanced Auto Connect is partof the AMR feature and is mentioned here only to point out that GSM HR will enjoy thesame benefit.

The backhaul requirements between the BTS and BSC may also be reduced to 8kbps aslong as subrate (8K) switching is present at the BSC. Both GDP and GDP2 boards willbe enhanced to support GSM HR. GDP will be introduced first, followed by GDP2 in afuture release.

Version 1 Rev 0 Half Rate



6–3

Half Rate

SYS12_ch1_13

432107654321076543210765 432107654321076543210765 5

432107654321076543210765 432107654321076543210765 5

Full Rate Speech

Half rate channel

Half rate channel

Version 1 Rev 0Adaptive Multi–Rate (AMR)



6–4

Adaptive Multi–Rate (AMR)Adaptive Multi–Rate (AMR) is introduced in GSR7 and provides two modes of workingAMR full–rate channel mode (AMR FR) and AMR half–rate channel mode (AMR HR).

AMR Full – Rate Channel ModeThis mode of working provides higher speech quality in areas of poor RF conditions.

Full Rate Link AdaptationAMR FR link adaptation works in conjunction with the rest of the AMR feature set, namely AMR,Call downgrade on CIC capability mismatch and Enhanced GDP provisioning. It provides improvedspeech quality in poor RF environments by adapting the speech rates and level of error correctionon a call. Speech quality is improved by reducing the speech rate and increasing the level of errorcorrection in poor RF environment. The speech rate used is determined by the codec mode used.The Active Codec Set (ACS) refers to the set of up to 4 AMR codec modes that can be utilised forany given voice call in the uplink and downlink direction.

AMR Half – Rate Channel ModeThis mode of working allows two AMR calls to be placed on a single air interfacetimeslot. This gives an increase in cell capacity with no additional hardware. Howeverextra backhaul is required between BSC and BTS due to there being no 8kbps switchingin release GSR7. This means that AMR half–rate speech data has to be carried in16kbps TRAU format between BSC and BTS. Given that potentially 16 AMR half–ratecalls can be supported on an AMR half–rate carrier, an AMR half–rate RTF must havefour associated E1 timeslots provisioned between BSC and BTS.

Due to reduced bandwidth, an AMR half–rate call will in general have a lower QoS than afull–rate call. For this reason the user will be able to specify a congestion level that has tobe exceeded in an AMR half–rate cell before new calls will be assigned to a half–ratechannel. In addition, when the received bit error rate (Rxqual) indicates that a half ratechannel is suffering interference and that the speech quality of the call is thereforeimpaired, an intra–cell handover back to full–rate (or to another half–rate channel) issupported to maintain quality of service.

There is also a lower QoS provided by AMR half–rate calls.

Half Rate Link AdaptationAMR HR link adaptation operates in a similar way to AMR FR link adaptation. The differences arethe bit rates of the HR codec modes supported, different initial HR codec mode and differentassociated uplink and downlink codec mode adaptation thresholds and hystersis values.

Active Codec Set ValuesIn total there are 8 Active Codec Set values.

0 12.20 kbps1 10.20 kbps2 7.95 kbps3 7.40 kbps4 6.70 kbps5 5.90 kbps6 5.15 kbps7 4.75 kbps

The BSS supports:–

12.1, 10.2, 7.4, 6.7 and 5.15 kbps for a full rate channel.

7.95, 7.4, 6.7, 5.9 and 5.15 kbps for a half rate channel.

Version 1 Rev 0 Adaptive Multi–Rate (AMR)



6–5

Adaptive Multi–Rate (AMR)

SYS12_amr_01

MSC RXCDR BSC BTS

0

For half rate rtf – two E1 timeslots required

Dependant on:–Enhanced GDP Provisioning–Call downgrade on CIC

capability mismatch

Up to four codecmodes can beincluded in FR and

HR Active CodecSet

Which Codec Modeused depends onRF conditions

Up to 16 AMR half rate calls

Up to 8 AMR full rate calls

Or a combination of the two.

Version 1 Rev 0AMR Half–Rate Further Considerations



6–6

AMR Half–Rate Further ConsiderationsThe operator may set a database parameter in order to override any MSC channel ratepreference (if given) and the cell’s congestion threshold, causing AMR calls to beassigned directly to Half–Rate channels. This allows temporary forcing (from the OMC) ofHalf–Rate usage during busy periods. Intra–Cell handovers for quality reasons fromHalf–Rate are still permitted when the override flag is set, but the target resource for theintra–cell handover will be forced to half–rate.

In addition to the ability to specify that new ’half–rate capable’ calls should be assignedto half–rate traffic channels when cell congestion exceeds the threshold, the operator willhave the ability to specify a second (or alternative) congestion threshold. When thiscongestion threshold is exceeded in an AMR half–rate channel mode cell, the BSS SWwill re–assign ’half–rate capable’ full–rate calls to half–rate traffic channels.

Congestion and quality–related intracell handovers can occur between AMR FR andAMR HR channel modes, and between GSM FR/EFR and AMR HR. The followingconditions apply to determination of a ’half–rate capable call’ for either congestionbased FR–HR intracell handovers or quality based half–rate intra–cell handovers:

� The MSC must identify to the BSC that the call is capable of both channel types and at least one FR and one HR (the AMR HR) speech version in the Channel Type IE in the Assignment Request or Handover Request .

� The identified FR and HR speech versions must be enabled at the BSS level (AMR FR/AMR HR/EFR) and Cell level (AMR FR/HR).

� The MSC must not specify that ’rate changes not allowed after initial assignment’ in the Channel Type IE.

Note: If ’rate changes not allowed after initial assignment’ is specified by the MSC,the BSS must only allow the call to use the channel type allocated initially. Therefore anyprocedures, such as congestion based FR–HR intra–cell handovers or quality basedhalf–rate intra–cell handovers, which will result in a channel rate change are not allowed.

� The specified CIC for the call must be AMR capable (uses the transcoding resources of an enhanced transcoding GDP), which means that it will support half–rate and all of the FR speech versions. Note that if the CIC used changes during the call (at the request of the MSC), the call may become routed onto a basic GDP or XCDR, and so it shall no longer be a half rate capable call.

The portion of the feature relating to handover of existing Full–Rate calls to Half–Rate isused in conjunction with the Congestion Relief feature, and verifies that this feature is inuse. Mobiles which are considered the best candidates for using Half–Rate are thoseclosest to the centre of the cell, as indicated by those not included in the power budgetcriterion for standard Congestion Relief (handing over to the strongest neighbour cell).

Version 1 Rev 0 AMR Half–Rate Further Considerations



6–7

AMR Half–Rate Further Considerations

SYS12_amr_02

MSC RXCDR BSC BTS

Assignment or Handover Request Msg–At least one FR and one AMR HR

speech version in the channel type IE–MSC must not specify ’rate changes

not allowed after initial assignment’ inthe channel type IE

Identified AMR FR and AMRHR must be enabled at celllevel

G

DP

Specified CIC for the call must beAMR capable (Enhanced GDP)

Identified AMR FR and AMRHR must be enabled at BSSlevel

Version 1 Rev 0Enabling Half Rate



6–8

Enabling Half RateMany of the parameters associated with the AMR feature are generic to both Half Rateand AMR. In the case of enabling Half Rate there are two new parameters unique to halfRate.

At BSS level

chg_element gsm_bss_half_rate_enabled <*> <location>

<*> 0 = Disabled

1 = Enabled

In the case of remote transcoding the AXCDR must have CIC validation enabled. Also ifthe parameter handover_required_sp_ver_used is disabled this parameter will not beallowed to be enabled.

At cell level

chg_element gsm_half_rate_enabled <*><site no>cell = <cell_id>

<*> 0 = Disabled

1 = Enabled

The GSM Half Rate feature can only be used at sites comprised of Horizonmacro,Horizonmacro2, MCell2 or MCell6 cabinets. Or a combination of these cabinets.

RTF Change

If the AMR Half Rate or GSM Half Rate feature is enabled then when the RTF’s areequipped two further prompts will appear. One to state whether Half Rate is enabled onthat RTF and the other to state whether 8kbps of TRAU is allowed on that RTF.

Note: If AMR half Rate is enabled and the 7.95kbps Codec Mode exists in the ActiveCodec Set the 8kbps TRAU option will not be prompted.

Example:

equip 1 rtf

Existing equip outputs unchanged

Enter the value for Half Rate enabled = 1Is 8kbps TRAU allowed (yes/no)?: yes

Existing equip outputs unchanged

COMMAND ACCEPTED

Version 1 Rev 0 Enabling Half Rate



6–9

Enabling Half Rate

SYS12_amr_02a

BTS

BSCEnabling\Disabling pararmeters per BSS

gsm_bss_half_rate_enabled

Single Zone cellMulti–Zone Cell

Enabling\Disabling parameters per Cell

gsm_half_rate_enabled

MSC

Handover request or assignment request

required channel is half–rate

Equiping RTF’s

half_rate_enabled

Allow_8k_trau

Version 1 Rev 0Channel Allocation for AMR



6–10

Channel Allocation for AMRIn the Channel Type information element within the Handover Request and AssignmentRequest messages from the MSC there is a “Speech/data indicator ” octet. This defineswhether the request is for speech, data or signalling. the operation of the BSS is differentfor each option.

Speech

The ’Channel rate and type ’ octet contained within the Channel Type Informationelement in the Handover request and Assignment request messages from the MSCcontains the following:

� Required channel rate – i.e. Full–rate, half–rate or either full–rate or half–rate.

� In the case of either, the preferred channel rate may be indicated.

� In the case of either, whether rate changes are permitted after initial channel allocation may also be indicated.

Also the ’permitted speech version indication ’ octets within the channel typeinformation element list is in order of preference, the speech versions which maybe usedfor the call.

Full–rate Channel Required

If the MSC specifies that a call must be allocated a full rate channel by setting the’Channel rate and type ’ octet within the Channel type information element in anassignment request or handover request message to a ’full rate TCH channel Bm ’.

AMR Half–rate Channel Required

If an assignment request or handover request message from the MSC specifies the’Channel rate and type ’ octet within the channel type information element as ’half rateTCH channel Lm ’ the BSS will attempt to allocate a half rate channel to the call if ’GSMspeech half rate version 3 ’ is in the ’permitted speech version indication ’ list. If notthe BSS rejects the request.

The BSS can only allocate an AMR half–rate channel if the following are true:

� The AMR half–rate channel mode is enabled at BSS level

� The AMR half–rate channel is enabled for the target cell

� There are AMR half–rate channels available in the target cell and the MSC specifies that AMR half–rate

If none of these are true and the MSC specifies that an AMR half–rate channel is to beused, then the BSS rejects the assignment/handover request . This is done by sendingan assignment failure message to the MSC which can have the cause value ’requestedspeech version unavailable ’ for AMR being disabled, or ’no radio resource available ’for the case of no AMR half–rate channel resources being available in the target cell.

Version 1 Rev 0 Channel Allocation for AMR



6–11

Channel Allocation for AMR

ch6_amr_en/dis

BTS

BSCEnabling/Disabling parameters per BSS

amr_bss_half_rate_enabled

Single Zone cell Multi–zone cell

Enabling/Disabling parameters per cell

amr_half_rate_enabled

MSC


required channel is half–rate

chg_element amr_bss_half_rate_enabled <*><location>

<*> 0 = Disabled

1 = Enabled

chg_element amr_half_rate_enabled <*><site> cell = <cell_id>

<*> 0 = Disabled

1 = Enabled

Note: CIC Validation must be enabled and in the case of handovers the’handover_required_speech_ver_used ’ must also be included in the handover requiredmessage.

Version 1 Rev 0Force Half–Rate



6–12

Force Half–RateIn the case of the MSC specifying that either a full–rate or a half–rate channel can beallocated to a call, the BSS decides what to allocate. The BSS will attempt to allocate afull–rate channel to the call if any of the following are true:

� The AMR or GSM half–rate channel mode is disabled at BSS level

� The AMR or GSM half–rate channel mode is disabled for the target cell

� The ’Channel rate and type’ octet indicates that rate changes after initial channel allocation are not allowed

� The CIC selected for the call does not have (AMR) half–rate capability.

In addition to this if there is no preferred channel rate , or that a full–rate channel ispreferred. The BSS will attempt to allocate a full–rate to the call unless the criteria is metwhich allows the BSS to ignore the precedence specified by the MSC. The criteriagoverning this procedure is two fold.

� The force_hr_usage per BSS element is set.

chg_element force_hr_usage <*> <location>

<*> 0 = disabled

1 = enabled

� The per cell new_calls_hr congestion level has been exceeded.

This congestion threshold indicates at what congestion level the BSS SW should startassigning new ’half–rate capable’ calls as AMR or GSM half–rate calls. A limitationexists based on the number of idle half–rate channels and free generic traffic channels inthe cell.

chg_cell_element new_calls_hr <*> cell = <cell_id>

<*> 0 to 101(%)

Setting this element to 101 effectively disables the new calls at half–rate congestionmechanism.

Reconfiguration of Existing Full–Rate Calls

The BSS supports the configuration of the new reconfig_fr_to_hr congestion thresholdon a per–cell basis to indicate at what congestion level the BSS SW should instigatereconfiguration of “half–rate capable” full–rate calls to AMR or GSM half–rate calls.

chg_cell_element reconfig_fr_to_hr <*> cell = <cell_id>

<*> 0 to 101(%)

Setting this element with a value of 101 effectively disables the reconfigure half–rate fullrate calls to half–rate congestion mechanism.

Version 1 Rev 0 Force Half–Rate



6–13

Force Half–Rate

ch_6_amr_force

BTS

BSC

Per BSS parameter to force full–rate calls

to AMR or GSM half rate

force_hr_usage

Single Zone cell Multi–Zone cell

Congestion parameter for forcing half–rate capable calls to AMR or GSM half rate

new_calls_hr

MSC


– required channel is full rate or half–rate capable

reconfig_fr_to_hr

Version 1 Rev 0Reservation of Half–Rate Resources



6–14

Reservation of Half–Rate ResourcesThe operator will have the ability to reserve a number of half–rate resources (on generictimeslots) for use in congestion. Full–Rate calls are prevented from using theseresources until there are no other timeslots available in the cell/zone. The reservedgeneric timeslots will be applied to the inner and outer zones within a multi–zone cell. Forexample, if the operator specifies to reserve two generic timeslots, this will result in twotimeslots being reserved on the inner zone and two timeslots being reserved on the outerzone.

It should be noted that the reservation of generic timeslots is applied to each zone withinmulti–zone cells (Concentric Cell, Dual Band Cell). Within a cell that does not supportmultiple zones, all the cell resources are considered to be in the outer zone.

The hr_res_ts element specifies the maximum number of half–rate capable timeslots tobe reserved within each zone of the cell. Within the inner zone, the actual value can bedynamically limited to be less than hr_res_ts, if the BSS detects that theinner_hr_usage_thres will not be able to be exceeded because of the setting ofhr_res_ts . hr_res_ts is also limited by the number of half–rate capable resourcesavailable in the cell or zone. There are no specific dedicated Half–Rate reservedtimeslots. Any timeslot on a Half–Rate capable carrier can be considered ’reserved’ ifFull–Rate calls have not been assigned to them due to there only being hr_res_tsnumber of timeslots left in the cell/zone.

chg_element hr_res_ts <*><site> cell = <cell_id>

<*> 0 to 2558

Default = 2

Version 1 Rev 0 Reservation of Half–Rate Resources



6–15

Reservation of Half–Rate Resources

SYS!”_amr_10

BTS

Single Zone cell Multi – Zone Cell

Reservation of timeslots for half–rate usage

hr_res_ts

Version 1 Rev 0AMR Full – Rate Link Adaptation



6–16

AMR Full – Rate Link AdaptationFull Rate AMR Link Adaptation provides the mechanism by which the BSS adaptsbetween speech codec modes in an AMR codec on the uplink and downlink of an AMRFR call, to provide the most suitable level of error correction for the RF environment.Uplink and downlink codec modes are considered separately and can be adaptedseparately. The AMR feature provides a set of Full Rate codec modes. With Full RateLink Adaptation, up to four of these codec modes could be placed in the per cell FullRate Active Codec Set. It is over this Active Codec Set that the call is adapted accordingto the quality of the link between the mobile and the BSS. The Full Rate codec modessupported are:

AFS 12.2 kbps

AFS 10.2 kbps

AFS 7.4 kbps

AFS 6.7 kbps

AFS 5.15 kbps

The higher the bit rate of the codec mode indicated the higher the speech rate and thelower the error correction rate. Upto 4 of these codec modes can be included in the FRACS.

For each pair of codec of modes there is an associated threshold and hysteresis value.The associated threshold is used as the lower decision threshold for switching the codecmode to a lower mode with a lower speech rate. The sum of the associated thresholdand associated hysteresis is used as the upper decision threshold for switching thecodec mode to a less robust mode with a higher speech rate. The threshold andhysteresis are expressed in terms of normalized Carrier to Interference (C/I) values.

CODEC_MODE_1 Represents the lowest codec mode (lowest speech bit rate, highest error correction bit rate) of the FR ACS

CODEC_MODE_2 Represents the second lowest codec mode, if the ACS contains more than one codec mode.

CODEC_MODE_3 Represents the third lowest codec mode, if the ACS contains more than two codec modes.

CODEC_MODE_4 Represents the highest codec mode (highest speech bit rate, lowest error correction bit rate) of the ACS if the ACS contains four codec modes.

The FR ACS, Full Rate Initial Codec mode and the associated codec mode adaptationthreshold and hysteresis values to be used are communicated to the mobile and thechannel coder on call initialization and handover.

FR AMR codecs provide different levels of error correction and allow different channel biterror rates for acceptable quality of service. As an example, at the lowest codec mode(low speech rate, high error correction) a larger BER may be acceptable as more of theerrors will be corrected, where as in a higher codec mode a larger BER would beunacceptable as less errors will be corrected. The differences in AMR channelcharacteristics prompt the introduction for a new set of HDPC RXQUAL algorithmthresholds. The new HDPC parameters are specific to AMR FR calls and utilize theexisting GSM Handover and Power Control algorithms. These new HDPC parametersallow an AMR FR capable cell to be tailored for AMR FR capable mobiles, to increasethe range of cells and improve service in poor coverage areas, minimize interferencelevels to improve speech quality, increase capacity (through tighter–reuse of frequencies)and increase service quality by lowering the number of handovers for AMR FR. Thisrelease of Full Rate Link Adaptation is tailored towards maximizing speech quality andhence all defaulted values supplied in the software are geared to that goal.

Version 1 Rev 0 AMR Full – Rate Link Adaptation



6–17

AMR Full–Rate Link Adaptation

SYS12_amr_3

Available Full Rate

Codec Modes

AFS 12.2 kbps

AFS 10.2 kbps

AFS 7.4 kbps

AFS 6.7 kbps

AFS 5.15 kbps

Up to 4 can be

chosen

C/IC/I

THR3

THR3 + HYST3

THR2

THR1 + HYST1

THR2 + HYST2

THR1

CODEC_MODE_1

CODEC_MODE_2

CODEC_MODE_3

CODEC_MODE_4

Version 1 Rev 0AMR Half – Rate Link Adaptation



6–18

AMR Half – Rate Link AdaptationHalf Rate AMR Link Adaptation provides similar functionality to Full Rate AMR LinkAdaptation but for the Half Rate AMR channel. In Half Rate AMR Link Adaptation there isa different Half Rate Active Codec Set. This AHS can contain up to four of the Half RateAMR codec modes that are supported. The Half Rate codec modes supported are AHS7.95 kbps, 7.4 kbps, 6.7 kbps, 5.9 kbps and 5.15 kbps. There is also a different Half RateInitial Codec Mode and different associated uplink and downlink codec mode adaptationthresholds and hysteresis values for Half Rate AMR calls. The existing GSM Handoverand Power Control algorithms are still used for the Half Rate AMR channel, but similar toFull Rate Link Adaptation a new set of Handover and Power Control thresholds areintroduced. The new Half Rate AMR HDPC RXQUAL thresholds are different to the FullRate AMR HDPC thresholds because the Half Rate channel will display differentcharacteristics to a Full Rate AMR channel. For these reasons the customer may wish toconfigure the Handover and Power Control algorithms in a different manner to cater forthe Half Rate AMR channel. The MS Monitor introduced in Full Rate AMR LinkAdaptation also applies to Half Rate AMR calls.

CODEC_MODE_1 Represents the lowest codec mode (lowest speech bit rate, highest error correction bit rate) of the HR ACS

CODEC_MODE_2 Represents the second lowest codec mode, if the HR ACS contains more than one codec mode.

CODEC_MODE_3 Represents the third lowest codec mode, if the HR ACS contains more than two codec modes.

CODEC_MODE_4 Represents the highest codec mode (highest speech bit rate, lowest error correction bit rate) of the HR ACS if the ACS contains four codec modes.

Version 1 Rev 0 AMR Half – Rate Link Adaptation



6–19

AMR Half–Rate Link Adaptation

SYS12_amr_5

Available Half Rate

Codec Modes

AHS 7.95 kbps

AHS 7.4 kbps

AHS 6.7 kbps

AHS 5.9 kbps

AHS 5.15 kbps

Up to 4 can be

chosen

C/IC/I

THR3

THR3 + HYST3

THR2

THR1 + HYST1

THR2 + HYST2

THR1

CODEC_MODE_1

CODEC_MODE_2

CODEC_MODE_3

CODEC_MODE_4

Version 1 Rev 0Enabling/Disabling Link Adaptation



6–20

Enabling/Disabling Link AdaptationIt is possible in certain situations to disable Link Adaptation for calls in a cell. This isachieved by the use of four parameters.

chg_element amr_fr_dl_la_enabled <*><site>cell = <cell_id>

<*> 0 – disabled

1 – enabled

Default = 1

chg_element amr_fr_ul_la_enabled <*><site>cell = <cell_id>

<*> 0 – disabled

1 – enabled

Default = 1

chg_element amr_hr_dl_la_enabled <*><site>cell = <cell_id>

<*> 0 – disabled

1 – enabled

Default = 1

chg_element amr_hr_ul_la_enabled <*><site>cell = <cell_id>

<*> 0 – disabled

1 – enabled

Default = 1

Version 1 Rev 0 Enabling/Disabling Link Adaptation



6–21

Enabling/Disabling Link Adaptation

SYS12_amr_11

Single Zone cell Multi – Zone Cell

BTS

amr_fr_dl_la_enabled

amr_fr_ul_la_enabled

amr_hr_dl_la_enabled

amr_hr_ul_la_enabled

Enabling \ Disabling Parameters Per Cell

BSC

Version 1 Rev 0AMR FR/HR Commands to Specify ACS and Associated Parameters



6–22

AMR FR/HR Commands to Specify ACS and AssociatedParameters

The database parameter chg_acs_params is dealt with here. For this parameter to takeeffect the BTS type must be AMR capable. Namely these are solely Horizonmacrocabinets, solely MCell2/6 cabinets or a mixture of Horizonmacro and MCell2/6. The AMRfirmware is available on CTU, TCUA and TCUB. Also AMR Full–Rate or Half–Rate mustbe enabled in the cell for the AMR parameters to come into effect. This command allowsthe parameters to be set before or after AMR is enabled in the cell, thereby allowing theperformance to be optimised for calls subsequently initiated in the cell.

chg_acs_params <mode> <cell_id>

mode = 0 Full rate 1 Half rate 2 Both rates

This command is used to specify up to 4 codec modes, to be used in the ACS,associated thresholds and hysteresis values for the cell.

Depending on whether Full rate, Half rate or both is entered a number of further promptsare displayed. On this page are the prompted parameters for Full rate.

Active Codec Set values 0 12.20kbps 1 10.20kbps 2 7.95kbps 3 7.40kbps

4 6.70kbps 5 5.90kbps 6 5.15kbps 7 4.75

The BSS supports 12.2, 10.2, 7.4, 6.7 and 5.15kbps for a FR channel.

Enter AMR Full Rate active codec set : Range 0,1,3,4 and 6

Parameter: amr_fr_acs

Description: Up to 4 AMR codec modes that can be used for any given voice call in theuplink or downlink direction.

Default (0,1,3 and 6)

Enter AMR Full Rate initial codec mode : Range 0,1,3,4 and 6

Parameter: amr_fr_initial_codec_mode

Description: Codec mode used at the beginning of a call. If one mode is entered for FRACS, then the FR Initial Codec Mode will default to this if valid.

Default: 1

Enter AMR Full Rate uplink adaptation thresholds : Range 0 to 63 (0.5dB steps)

Parameter(s): amr_fr_uplink_threshold3 amr_fr_uplink_threshold2 amr_fr_uplink_threshold1

Description: Lower Full–rate uplink decision threshold for switching from one mode toanother.

Default: 20, 14 and 9 (10dB, 7dB and 4.5dB).

Version 1 Rev 0 AMR FR/HR Commands to Specify ACS and Associated Parameters



6–23

Full–Rate Example

SYS12_amr_06

MMI – RAM 0115 –> chg_acs_params 0 2 3 4 0 2 678 01

Enter AMR Full Rate active codec set : 1 3 4 6

Enter AMR Full Rate initial codec mode : 1

Enter AMR Full Rate uplink adaptation thresholds : 40 30 20

Enter AMR Full Rate uplink adaptation hysteresis : 1 1 2

Enter AMR Full Rate downlink adaptation thresholds : 45 35 25

Enter AMR Full Rate downlink adaptation hysteresis : 1 1 2

Enter AMR Full Rate uplink adaptation thresholds for frequency hopping : 16 11 4

Enter AMR Full Rate uplink adaptation hysteresis for frequency hopping : 1 1 1

Enter AMR Full Rate downlink adaptation thresholds for frequency hopping : 27 22 14

Enter AMR Full Rate downlink adaptation hysteresis for frequency hopping : 1 1 1

COMMAND ACCEPTED

AMR Full Rate active codec set : 1

AMR Full Rate initial codec set : 1

Note: In this example previously only one mode was configured

Version 1 Rev 0AMR FR/HR Commands to Specify ACS and Associated Parameters–Cont’d



6–24

AMR FR/HR Commands to Specify ACS and AssociatedParameters–Cont’d

Enter AMR Full Rate uplink adaptation hysteresis : Range 0 to 15 (0.5dB steps)

Parameter(s): amr_fr_uplink_hystersis3amr_fr_uplink_hystersis2amr_fr_uplink_hystersis1

Description: The sum of the associated threshold and hysteresis is used as the upperdecision threshold for switching the codec mode.

Default: 1,1,1 (0.5dB).

Enter AMR Full Rate downlink adaptation thresholds : Range 0 to 63 (0.5dB steps)

Parameter(s): amr_fr_downlink_threshold3 amr_fr_downlink_threshold2 amr_fr_downlink_threshold1

Description: Lower Full–rate downlink decision threshold for switching from one mode toanother.

Default: 30, 24 and 19 (15dB, 12dB and 9.5dB).

Enter AMR Full Rate downlink adaptation hysteresis :

Parameter(s): amr_fr_downlink_hystersis3amr_fr_downlink_hystersis2amr_fr_downlink_hystersis1

Description: The sum of the associated threshold and hysteresis is used as the upperdecision threshold for switching the codec mode.

Default: 1,1,1 (0.5dB).

Enter AMR Full Rate uplink adaptation thresholds for frequency hopping: Range 0 to 63 (0.5dB steps)

Parameter(s): amr_fr_uplink_threshold3_hoppingamr_fr_uplink_threshold2_hoppingamr_fr_uplink_threshold1_hopping

Description: Uplink switching thresholds applied to frequency hopping channels.

Default: 16, 11 and 4 (8.0dB, 5.5dB and 2.0dB)

Enter AMR Full Rate uplink adaptation hysteresis for frequency hopping:Range 0 to 15 (0.5dB steps)

Parameter(s): amr_fr_uplink_hystersis3_hoppingamr_fr_uplink_hystersis2_hoppingamr_fr_uplink_hystersis1_hopping

Description: Uplink hysteresis applied to frequency hopping channels

Default: 1, 1, 1 (0.5dB)

Enter AMR Full Rate downlink adaptation thresholds for frequency hopping:Range 0 to 63 (0.5dB steps)

Parameter(s): amr_fr_downlink_threshold3_hoppingamr_fr_downlink_threshold2_hoppingamr_fr_downlink_threshold1_hopping

Version 1 Rev 0 AMR FR/HR Commands to Specify ACS and Associated Parameters–Cont’d



6–25

Full–Rate Example Non–Hopping

SYS12_amr_07

THR3

THR3 + HYST3

THR1

20 + 0.5 = 20.5dB Uplink

22.5 + 0.5 = 23dB Downlink

20dB Uplink

22.5dB Downlink

THR2

THR2 + HYST2

15 + 0.5 = 15.5dB Uplink

17.5 + 0.5 = 18dB Downlink

15dB Uplink

17.5dB Downlink

THR1 + HYST1

10dB Uplink

12.5dB Downlink

10 + 1 = 11dB Uplink

12.5 + 1 = 13.5dB Downlink

CODEC_MODE_1

1 – 10.2kbps

CODEC_MODE_2

3 – 7.4kbps

CODEC_MODE_3

4 – 6.7kbps

CODEC_MODE_4

6 – 5.15kbps

InitialCodecMode

Version 1 Rev 0AMR FR/HR Commands to Specify ACS and Associated Parameters–Cont’d



6–26

Description: Downlink switching thresholds applied to frequency hopping channels

Default: 26, 21 and 14 (13.0dB, 10.5dB and 7.0dB)

Enter AMR Full Rate downlink adaptation hysteresis for frequency hopping: Range 0 to 15 (0.5dB)

Parameter(s): amr_fr_downlink_hystersis3_hoppingamr_fr_downlink_hystersis2_hoppingamr_fr_downlink_hystersis1_hopping

Description: Downlink hysteresis applied to frequency hopping channels.

Default: 1,1,1 (0.5dB)

Downlink Adaptation Change Minimum Time Period

In the case of downlink adaptation procedure it is possible to specify the minimum timeperiod between initiating changes in the downlink codec mode. When the parameter isset to a value greater than the inherent delay in the adaptation process, a wait period isadded to slow down the adaptation.

chg_element amr_dl_la_mode_chg_min <*> 0

<*> 0 to 255 (ms) Default = 100ms

Version 1 Rev 0 AMR FR/HR Commands to Specify ACS and Associated Parameters–Cont’d



6–27

Full–Rate Example Hopping

SYS12_amr08

C/IC/I

THR3

THR3 + HYST3

THR1

8 + 0.5 = 9.5dB Uplink

13.5 + 0.5 = 14dB Downlink

8dB Uplink

13.5dB Downlink

THR2

THR2 + HYST2

5.5 + 0.5 = 6dB Uplink

11 + 0.5 = 11.5dB Downlink

5.5dB Uplink

11dB Downlink

THR1 + HYST1

2dB Uplink

7dB Downlink

2 + 0.5 = 2.5dB Uplink

7 + 0.5 = 7.5dB Downlink

CODEC_MODE_1

1 – 10.2kbps

CODEC_MODE_2

3 – 7.4kbps

CODEC_MODE_3

4 – 6.7kbps

CODEC_MODE_4

6 – 5.15kbps

Initial

Codec

Mode

Version 1 Rev 0MS Monitor Functionality



6–28

MS Monitor FunctionalityFull Rate AMR Link Adaptation introduces MS Monitor functionality that monitors andcompensates for the inability of some mobiles to accurately estimate the currentconditions of the channel that it is using. The threshold and hysteresis values supplied forAMR calls by the network at call initialization may be ineffective for some mobiles incertain RF conditions. The MS Monitor is introduced as a mechanism to adjust thedownlink codec mode adaptation thresholds during a call so that the MS is able tocorrectly adapt across the ACS as needed. The MS Monitor works by monitoring amobile during a call and detecting conditions that indicate that the downlink codec modeadaptation thresholds need adjusting. The MS Monitor will decrease the thresholds at theMS if they are deemed to be too high and increase the thresholds if they appear to be toolow. If a mobile’s thresholds are too low, i.e. the range of C/I values that the MS ismeasuring is below the lowest threshold in the ACS, then the mobile will request thelowest codec mode whilst simultaneously indicating to the network that that call is in verygood RF quality conditions. The mobile could operate very well in these conditions in thehighest codec mode. The Monitor checks these conditions over a certain period of timeand if the quality of the call is high enough then the downlink adaptation thresholds will bemodified in the mobile. Similarly, the MS Monitor will increase the thresholds at themobile if the network sees that the MS is requesting the highest codec mode, whilstindicating that the call is in poor RF quality conditions, as this would indicate that therange of C/I values measured by the mobile were above the highest threshold in theACS.

Downlink Adaptation MS Monitor ParametersThe BSS MS Monitor, monitors AMR mobiles over a period defined asamr_ms_monitor_period and collects CMR values and RXQUAL values. At the end ofthis period the data that has been collected is processed and a decision made whether ornot to adapt the thresholds used by the mobile. The BTS shall monitor the Codec ModeRequest values for individual calls in order to determine mobiles for which the downlinkadaptation thresholds should be adjusted.

chg_element amr_ms_monitor_period <*> 0

<*> 10 to 120 (SACCH) Default = 40 (SACCH)

Description: Used for detecting MSs continually requesting the highest or lowest modes.

chg_element amr_ms_high_cmr <*> 0

<*> 50 to 100 (%) Default = 99%

Description: Percentages for monitoring AMR MSs continually requesting the highest codec mode.

chg_element amr_ms_low_cmr <*> 0

<*> 50 to 100 (%) Default = 95%

Description: Percentages for monitoring AMR MSs continually requesting the lowest codec mode.

chg_element amr_ms_high_rxqual <*> 0

<*> 0 to 7 (QBand Units) Default = 2.5% BER or QBand Unit 4

Description: Threshold for monitoring AMR MSs continually requesting the highest codec mode.

chg_element amr_ms_low_rxqual <*> 0

<*> 0 to 7 (QBand Units) Default = 0.5% BER or QBand Unit 2

Description: Threshold for monitoring AMR MSs continually requesting the lowest codec mode.

chg_element amr_dl_thresh_adjust <*> 0

<*> 1 to 7 (dB) Default = 3dB

Description: For applying compensation to the C/I adaptation thresholds.

Version 1 Rev 0 MS Monitor Functionality



6–29

MS Monitor Functionality

SYS12_amr_12

0

7

4

2

Default

Default

Lower threshold for

monitoring AMR MSs

requesting the lowest

codec mode

Higher threshold for

monitoring AMR MSs

requesting the highest

codec mode

Rxqual Thresholds

When an AMR MS has requested

the lowest codec mode at least 95%

(def) of the monitoring period

(40SACCH def)

When an AMR MS has requested

the highest codec mode at least

99% (def) of the monitoring period

(40SACCH def)

Apply increase or decrease

to dl adaptation thresholds

Version 1 Rev 0(AMR) Half Rate Handover and Power Control Parameters



6–30

(AMR) Half Rate Handover and Power Control ParametersThe ability to set unique thresholds for power control and handovers is allowed. This isbecause the active codec set used in the cell will affect the thresholds. These additionalthresholds are AMR or GSM half rate specific, with existing parameters and levels stillapplicable for non–AMR calls. The Rxlev thresholds applied for an AMR or GSM half ratetraffic channel remain the same as for existing call types (e.g. GSM FR and EFRspeech).

Full Rate

l_rxqual_ul_p_amr_fr (Def 226 BER or 4 QBand)l_rxqual_ul_h_amr_fr (Def 453 BER or 5 QBand)l_rxqual_ul_h_hopping_amr_fr (Def 453 BER or 5 QBand)l_rxqual_ul_p_hopping_amr_fr (Def 113 BER or 3 QBand)l_rxqual_dl_p_amr_fr (Def 113 BER or 3 QBand)l_rxqual_dl_h_amr_fr (Def 226 BER or 4 QBand)l_rxqual_dl_h_hopping_amr_fr (Def 0 BER or 0 QBand)l_rxqual_dl_p_hopping_amr_fr (Def 0 BER or 0 QBand)

Half Rate

l_rxqual_ul_p_hr (Def 57 BER or 2 QBand)l_rxqual_ul_h_hr (Def 113 BER or 3 QBand)u_rxqual_ul_p_hr (Def 28 BER or 1 QBand)l_rxqual_ul_h_hopping_hr (Def 0 BER or 0 QBand)l_rxqual_ul_p_hopping_hr (Def 0 BER or 0 QBand)l_rxqual_dl_p_hr (Def 57 BER or 2 QBand)l_rxqual_dl_h_hr (Def 113 BER or 3 QBand)u_rxqual_dl_p_hr (Def 14 BER or 0 QBands)l_rxqual_dl_h_hopping_hr (Def 0 BER or 0 QBand)l_rxqual_dl_p_hopping_hr (Def 0 BER or 0 QBand)

All range values 0 to 1810 BER if alt_qual_proc = 0

0 to 7 QBand if alt_qual_proc = 1

Version 1 Rev 0 (AMR) Half Rate Handover and Power Control Parameters



6–31

(AMR) Half Rate Handover and Power Control Parameters

SYS12_amr_13

Rxqual Thresholds

BER QBands

l_rxqual_xx_x_xx

u_rxqual_xx_x_hr

0

1810

0

7

The ability to set

unique handover and

power control

thresholds for half rate

is supported

Version 1 Rev 0AMR or GSM Half–Rate Intracell Handovers



6–32

AMR or GSM Half–Rate Intracell HandoversThe support of intra–cell quality handovers for half–rate channels is provided by thedatabase parameter hr_intracell_ho_allowed .

For interference based handovers it further specifies the possible target channel typesi.e. full and/or half rate. A Half rate channel will be targeted where the BSSforce_half_rate usage flag is set, or in the case where half rate usage is linked tocongestion, if either the new_calls_hr or the reconfig_fr_hr thresholds have beenreached. A full rate channel will be targeted in all other cases.

For quality based intracell handovers, it is possible to either disable (by disabling allintracell handovers) or support targeting of a full rate resource. A half rate resource is nota supported target for quality based intracell handovers.

This has four settings listed below:

chg_element hr_intracell_ho_allowed <*> <site> cell = <cell_id>

<*> 0 – Half–rate intra–cell quality handovers are not initiated by the BSS. Handover required sent to the MSC.

1 – Half–rate intra–cell handovers are disabled. Handover required is not sent to the MSC.

2 – Half–rate intra–cell handovers are enabled. Full–rate only is allowed for interference and quality based handover.

3 – Half–rate intra–cell handovers are enabled. Half–rate and full–rate are allowed for interference based handover. Full–rate only allowed for quality based handover.

Related controls

force_hr_usage

When set will allow targeting of half rate channels for interference based handovers witha hr_intracell_ho_allowed setting of 3. Overriden by a setting of 2 (full rate only) andignored for settings of 0 or 1 (internal handovers either not supported or disabled).Unless disabled (settings of 0,1), quality based handovers will always target full ratechannels.

new_calls_hr /reconfig_fr_hr

When cell congestion exceeds either threshold, interference based handovers will targethalf rate channels with hr_intracell_ho_allowed setting of 3, full rate targeted with asetting of 2. Unless disabled (settings of 0, 1), quality based handovers will always targetfull rate channels.

Version 1 Rev 0 AMR or GSM Half–Rate Intracell Handovers



6–33

(AMR) Half–Rate Intracell Handovers

SYS12_amr_14

BTS

0

7

0

7

hr_intracell_ho_allowed (enabled)

Version 1 Rev 0AMR or GSM Half Rate Intra–cell Handover Hop Count



6–34

AMR or GSM Half Rate Intra–cell Handover Hop CountA unique hop count counter is provided for AMR or GSM half rate intra–cell qualityhandovers from half–rate channels is provided for by the database parameterhr_fr_hop_count .

chg_element hr_fr_hop_count<*><site> cell = <cell_id>

<*> 0 to 255 Default = 1

Used in conjunction with hr_intracell_ho_allowed to restrict the number of intracellhandovers between half rate and full rate in any one (hop_count_timer ) period (see alsohop_count ). For a call switching between a half rate channel and a full rate channel, theBSS shall disable intracell handovers and retain on a full rate channel when thisthreshold (and/or the existing hop_count threshold) is reached. Half rate support shallbe re–enabled at expiry of the hop_count_timer period.

hop_count

Used in conjunction with hr_intracell_ho_allowed to restrict the number of intracellhandovers. Considers existing full to full and new half to half and/or half to full ratehandovers. For half rate intracell handovers with full rate target channel support only(hr_intracell_ho_allowed settings of 2 or 3 based on handover type as above) eitherthis and/or hr_fr_hop_count being reached will disable intracell handovers from theallocated full rate channel for the remainder of the hop_count_timer period. This shallcover congestion based handovers requiring a half rate channel i.e. full rate calls withintracell handovers currently suspended due to reaching the hop_count limit shall not besubject to full to half rate reconfiguration when instigated for a cell. For a call on a halfrate channel with intracell handovers currently disabled, qualification for a quality basedintracell handover shall be considered as imperative and an intracell handover to full rateperformed where possible – as intracell handovers are disabled the call shall be retainedon the new full rate channel for the remainder of the hop_count_timer period.

Version 1 Rev 0 AMR or GSM Half Rate Intra–cell Handover Hop Count



6–35

AMR or GSM Half Rate Intra–cell Handover Hop Count

SYS12_amr_15

BTS

0

7

0

7

0

7

0

7

hr_fr_hop_count (reached) within hop_count_timer

Or for all intra–cell handovers hop_count (reached) within hop_count_timer

Version 1 Rev 0AMR or GSM Half Rate Intra–cell Handover Hop Count



6–36



7–1

Chapter 7

Planning of Microcells

Version 1 Rev 0



7–2

Version 1 Rev 0 Planning of Microcells



7–1

Planning of Microcells

Objectives

� Discuss the principles of planning microcells.

� Discuss frequency planning for microcells

� Calculate a microcell link budget.

� Discuss the antenna types used in microcellular

� Appreciate microcellular BTS products

� Discuss the antenna types for in–building cells

Version 1 Rev 0Steps in Planning Microcellular Systems



7–2

Steps in Planning Microcellular Systems

Identification of requirements

The first step in planning a microcellular system is to create a clear specification of therequirements for the final system; these requirements include the following points:

� Traffic requirements

� Quality of service (RF coverage, RXQUAL, Blocking)

� Coverage area

� Frequency planning

� Site surveys

� Specific areas of “strategic coverage” – Hotspots and poor RF coverage

� Indoor penetration requirements

� Antennal types and placements

� Base station products

� Equipment location

� E1 links backhaul

� Co–ordination with other operators

� Rate of system growth

Version 1 Rev 0 Steps in Planning Microcellular Systems



7–3

Identification of Requirements

Traffic requirements

Coverage area

Frequency planning

Site surveys

Quality of service

Indoor coverage requirements

Antenna types and placements

Base station products

Equipment location

Rate of system growth

E1 links backhaul

Co–ordination with other operators

sys12_ch04_01

Specific areas of “strategic coverage”

Version 1 Rev 0Quality of Service Targets



7–4

Quality of Service Targets

It is of great importance when designing a microcellular system to take into account theway offered traffic is to be handled. With increasing traffic, the behaviour of a multi–layermicrocell system is complex, therefore it is important from the outset to be clear aboutthe criteria which must be fulfilled in order to constitute a good system design. Someconsideration should be given to the following criteria:

� blocking probability for originations <= 2%

� sdcch blocking <=1%

� E1 link blocking <=1%

� system RF losses <= 2%

� (RXQUAL<=4) >= 98%

� mean handovers per call <= 2

� location updates per call <= 1

The first of these criteria is directly experienced by the user. The last criteria must be metso as to avoid overloading the BSS processing capability.

The actual behaviour of the system will depend upon user behaviour, variables such ascall distribution, speed distribution, repeat attempts etc. make it difficult to produce amodel which incorporates all of these aspects.

In order to achieve these criteria, very careful use of the handover algorithms andparameters is required. Careful consideration should also be given to the RF coverageas increasing the cell size will increase the traffic handled and vice versa. It has beenfound that the frequency plan can affect performance. The handovers per call figure donot show a strong dependence on the number of frequencies. The figures for RXQUALand RF losses however, improve greatly with the increased numbers of frequencies.

It is worth considering how existing customers may be affected when implementing themicrocells.

The aim is to ensure the quality of service is at least as good as the macrocell.

Version 1 Rev 0 Quality of Service Targets



7–5

Quality of Service Targets

sys12_ch04_02

Blocking probability for originations < = 2%

System RF losses < = 2%

(RXQUAL<=4) > = 98%

Mean handovers per call < = 2

Location updates per call < = 1

Subscriber profiles

SDCCH blocking < = 1%

E1 link blocking < = 1%

Version 1 Rev 0Traffic capacity enhancement



7–6

Traffic capacity enhancement

Erlang

Traffic capacity is measured in Erlangs. One Erlang equates to one traffic channelpermanently utilized for the period of measurement.

Erlang per subscriber

This factor is used to calculate the number of subscribers supported per cell. The factoris chosen from the network profile or actual usage from network statistics. For example ifthe average holding time for a call is 1 minute 30 seconds, as a fraction of an hour thatcomputes to 1/40th. That expressed that in decimal is 0.025, therefore we have 0.025Erlangs per subscriber, if that subscriber makes one call in that hour.

Channel Blocking

The standard model used to dimension a system is the Erlang B model. This gives us thenumber of traffic channels or trunks required or a given grade of service and givenordered traffic. There will be times when a call request is made and all channels or trunksare in use, this call is then blocked. The probability of this happening is the grade ofservice of the cell. If blocking occurs then the carried traffic will be less than the offeredtraffic. If a call is blocked, the caller may try again within a short period. Repeatedattempts cause the offered traffic to go above the level if there had been an absence ofblocking. Because of this factor offered traffic can be incorrect. But if the blockingprobability is small then this effect can be ignored.

Example

On the page opposite is an example scenario for a single macrocell with 3 microcellsdeployed.

Scenario assumptions;

� Erlangs supported by the 2 carrier macrocell = 8.20E (2 control channels 14TCH).

� Single carrier microcell support 2.94E.

� Dual carrier microcells support 9.01E.

� 0.025 Erlangs per subscriber.

� 2% blocking (grade of service).

Note:

For call originations it is dependant on what layer (micro or macro) the MS is in idlemode, as to what capacity is available (unless directed retry or congestion relief is used).The capacity of both layers is available for handovers.

Version 1 Rev 0 Traffic capacity enhancement



7–7

Traffic Capacity Enhancement

sys12_ch04_03

1409.20 *35.23 *4.30 *+3 micro (2 carrier)

(1 control channel)

3288.201Macro (2 carriers)

SubscriberOfferedTraffic

Capacity increasefactor

Combined cellscenario

Macrocell

Microcells

680.80 *17.02 *2.08 *+ 3 micro (1 carrier)

(1 control channel)

* If subscribers are inmicro coverage area

Version 1 Rev 0Traffic Capacity Enhancement Student Exercise



7–8

Traffic Capacity Enhancement Student Exercise

Our urban coverage in the example is maintained by a two–carrier macro cell using twocommon control channels. The subscriber density has risen to 2500 subscribers. Tocover all these subscribers with a GOS of 2% blocking, how many one–carrier, twocarrier or six carrier microcells would we need?

The average subscriber makes two calls per hour with each call lasting two minutes.

Assume that all microcells use just one control channel.

Version 1 Rev 0 Traffic Capacity Enhancement Student Exercise



7–9

Capacity Enhancement Student Exercise

First, calculate Erlang/Subscriber

No of calls =

Duration of call(s) =

Erlang/Subscriber = No of calls x call duration(s) = 3600

Next work out how many Erlangs of traffic need to be supported in the area.

Erlangs needed = Erlang/Subscriber x no. of subscribers

=

=

Remember: The macro will support traffic as well.

Therefore:

Resultant Erlangs needed = Erlangs needed – Erlangs supplied from the macrolayer (on page 4–7)

=

=

Single carrier microcell support at 2% grade of service =

Dual carrier microcell support at 2% grade of service =

Therefore the number of one–carrier microcells = Erlangs needed Single carrier microcell =

Therefore the number of two–carrier microcells = Erlangs needed = Dual carrier microcell

Therefore the number of six–carrier microcells = Erlangs needed = Six carrier microcell

Version 1 Rev 0Dimensioning of Signalling Channels



7–10

Dimensioning of Signalling Channels

Consideration should also be given to the required number of signalling channelsnecessary to handle the signalling generated by a microcellular system. There are threemain elements which must be dimensioned.

� Paging channels

� Access grant channels

� SDCCH channels

In order to do this, it is first necessary to have a prediction of the numbers of the varioustypes of transaction that will require resources, these are:

� Call set–ups

� SMS set–ups

� Supplementary Service invocations

� Location updates

� Attach/detach

An analysis of the potential traffic can be done by looking at existing Macrocell usage orthe use of planning tools (e.g. Hotspot detection software). Once a Microcell is installedoptimisation can take place to help get the signalling channel ratios correct.

It is wise to plan for any future expansion at this stage to ensure that the quality ofservice is not affected by sudden traffic growth in an area.

Version 1 Rev 0 Dimensioning of Signalling Channels



7–11

Dimensioning of Signaling Channels

sys12_ch04_04

8 SDCCH1 BCCH + 3

CCCH + 4

SDCCH

1221.9304

8 SDCCH1 BCCH + 9

CCCH88.20142

1 BCCH + 3

CCCH + 4

SDCCH

42.9471

2 x 8 SDCCH1 BCCH + 3

CCCH + 4

SDCCH

2021.04294

8 SDCCH1 BCCH + 3

CCCH + 4

SDCCH

128.20142

8 SDCCH1 BCCH + 9

CCCH82.2861

OtherTimeslots

Timeslot 0

Number ofSDCCHs

Number ofErlangs

Numberof TCHs

Numberof RTFs

Timeslot utilization

OtherTimeslots

Timeslot 0

Number ofSDCCHs

Number ofErlangs

Numberof TCHs

Number ofRTFs

Timeslot utilizationNumber ofRTFs

Tabl

e 1–

Sig

nalli

ngC

hann

els

(non

–LA

C)

Tabl

e 2

– S

igna

lling

Cha

nnel

s (L

AC

)

Version 1 Rev 0Planning for Hotspots



7–12

Planning for Hotspots

To recap hotsots are located where there is a high subscriber density. Therefore carefulliason with the customer should take place to identify where the traffic exists and whattype of traffic it is.

Further to this an initial inspection of the identified area should take place and potentialantenna sites located. It is a good idea to locate 3 or 4 potential sites so there is plenty ofchoice.

Only after this should the hotspot detector be used to select the best site.

Detection of Hotspot cells

The method used to detect hotspots is simply to place a test transmitter in a candidateHotspot location and transmit a dummy BCCH which is cell barred. The dummy BCCH istransmitted on a “clean” frequency for which the signal strength in the candidate test areais otherwise below some threshold value. The BSIC/frequency of this dummy BCCH isadded to the BA(SACCH) list of the macrocell for which the Hotspot is intended torelieve.

The measurement reports of mobiles operating on such a macrocell are analysed to seehow strongly they are reporting the dummy BCCH CTP. For a given level reported by themobile, and given hysteresis values, an assessment can be made of whether the mobilewould have handed over to the Hotspot cell, had it been a real cell in the neighbour list ofthe macrocell.

After analysis and assessment, an estimate can be made as to how much of the mobilepopulation in idle mode would have camped on the Hotspot cell, had it not been barred.

The attraction of using the Hotspot detector is that separate coverage checks toguarantee traffic are not necessary, the traffic is guaranteed by the very nature of theHotspot detector technique. Of course coverage checks may still be required to verifythat interference does not arise.

Appendix B contains a hotspot survey giving detailed information on this subject.

Version 1 Rev 0 Planning for Hotspots



7–13

Planning for Hotspots

sys12_ch04_06

Macrocell providingexisting coverage

Areas identifiedfor antennalocation

Measurement reportsof hotspot cell sent toserving BTS

Measurementreport analysed

by CTP

Version 1 Rev 0Frequency Planning



7–14

Frequency PlanningThere are two possibilities for microcell frequency planning, either reusing frequenciesfrom the macro layer or having a separate band for micros. However, between these twooptions a mixed strategy could be used.

Basically if we have hot spot cells or sparsely connected cells then having a separatefrequency spectrum for them would not be efficient. However, if it were a contiguousmicrocellular layer then it would be better to reserve a separate frequency spectrum as itwould be problematic to reuse frequencies in dense traffic areas (more on next page).

A mixed solution would be to have a small separate band for the microcellular layer anduse this wherever it is not possible to reuse frequencies from the macro layer. Forinstance if the micro layer had two carriers per cell then a possible solution would be tohave the separate band supplying the BCCH frequencies and reuse if necessary thecarriers supporting the non–BCCH carriers. A possible way of selecting whichfrequencies to use for the micro layer would be to scan the available frequency spectrumin the micro area, select any frequencies which fall below –90dBm and use those for themicro layer as macro frequency reuse.

When reusing frequencies from the macro layer, if frequency hopping is not being used,we can use frequencies from both the non–BCCH and BCCH frequencies. However, iffrequency hopping is being used in the macro–layer then it not advisable to reusefrequencies from the non–BCCH as any interference is hard to identify.

Example

If we take the case of a network with a total of 39 frequencies. In this network there is acombination of a dense city centre environment utilising microcell coverage and a lessdense areas also needing the use of micro cells to provide adequate coverage.

Macro Layer

In this network we are using a 5x3 reuse pattern meaning 15 frequencies are used asBCCH channels. The non–BCCH channels are using frequency hopping, the number offrequencies they hop over depends on whether the cells are located in the city centre oroutside the city centre. The city centre cells hop over 5 frequencies and the outside citycentre are hopping over 6 frequencies. The reason for this is the need to provide morefrequencies for the microcell layer in the city, so 1 of the hopping frequencies has beenused to provide this.

Micro Layer

There are 9 frequencies being used in the microcells in the city centre. These are madeup from: 6 of these frequencies are dedicated frequencies and the other 3 are the onesprovided from the frequencies excluded from the macro hopping channels.

This number is reduced to 6 (dedicated channels) outside the city centre.

Macro Layer Frequency Reuse

If there are no separate microcell frequencies available, then the macrocell BCCHfrequencies can be reused, as long as the macro interference is taken into account,based on its signal strength.

Version 1 Rev 0 Frequency Planning



7–15

Frequency Planning

sys12_ch04_07

Example 39 Frequencies Available

a1

a2

a3b1

b2

b3

d1

d2

d3

c1

c2

c3

e1

e2

e3

5x3 reuse pattern for macros = 15 frequenciesfor BCCH

City Centre

Additional 15 frequencies used for non–BCCHcarriers, hopping with a 3x1x5 reuse pattern

Outside City Centre

Additional 18 frequencies used for non–BCCHcarriers, hopping with a 3x1x6 reuse pattern

Macro Layer

Micro Layer

City Centre

9 Channels available – 6 dedicated, 3 fromfrequencies excluded for hopping frequencies

Outside City Centre

6 dedicated frequencies available only

Macrocell BCCH frequencies could be reused

Version 1 Rev 0Macro Frequency Reuse



7–16

Macro Frequency Reuse

The previous page states that it is theoretically possible to re–use macrocell frequencies.However, it must be emphasised that this is a theoretical analysis using;

� perfect grid locations

� identical antenna heights

� homogenous propagation

These factors all add to the variability in the overall picture, and mitigate against thegeneral re–use of macrocell frequencies in the microcells. There may be some caseswhere it can be confirmed, by means of the propagation tool or by measurement, that thesignal strength from a macrocell is sufficiently low at a microcell location so as not tocause interference. In this case the frequency could be re–used in a microcell. However,this is only likely to hold true for isolated microcells. Therefore the followingrecommendations are adopted;

It is preferred that microcell and macrocell layers should use distinct frequency bands.Occasional re–use of a macrocell frequency in the microcell layer may be possible, butthis should be confirmed by empirical tests on the system in question.

The next possibility to consider is the case where the macrocell frequency allocations areimmediately adjacent to each other. For example, if the microcell frequencies are 13 –18,then there is an adjacent channel problem. This will occur in the macrocell employingchannel 12.

A mobile operating on a microcell on channel 13 may not be able to decode the BSIC ofthe macrocell due to the difference in signal strength exceeding the adjacent channelprotection ratio. Thus the macrocell would not appear as a handover candidate and theinter–layer handover would not occur.

Conversely a mobile on the macrocell would see the microcell as an adjacent channelinterferer when it was in the coverage area of this microcell. This could lead to droppedcalls.

Leaving one guard channel between the micro and macro allocations alleviates thisproblem considerably, as the adjacent channel protection ratio is now 41dB. This meansthat the macrocell BSIC can be read over most of the coverage area of the microcell andconversely the area of a microcell over which a mobile on the macrocell will sufferinterference is greatly reduced.

This motivates the second recommendation;

At least one guard channel should be maintained between the frequencies in use in amacrocell and the frequencies in use in the microcells underlying that macrocell.

In cases where limited spectrum availability means that a guard channel is not possible, itmay be possible to invoke violations of the first recommendation to make the frequencyplan work. In the previous example where the microcell frequency groups are 13 –18,interference problems were experienced in the macrocell using channel 12.

It may be possible to engineer the microcell planning so that microcells that would haveused channel 13 use another channel (e.g. channel 10) instead. It is emphasised thatthat these macro/micro re–use cases should be checked by measurement.

Version 1 Rev 0 Macro Frequency Reuse



7–17

Macro Frequency Re–use

sys12_ch04_08

Guard Channel

It is recommended that macro and micro frequencies usedistinct frequency bands for ease of planning

Adjacent channel macro and micro frequencies could causeneighbours not to be decoded due to interference (micro

If a mobile was on the macro layer, it might see the microas a adjacent channel interferer, therefore it isrecommended that a guard channel is used.

Macro Frequencies

Micro Frequencies

source/macro neighbour) and.....

Version 1 Rev 0Requirements for Calculating Link Budgets



7–18

Requirements for Calculating Link Budgets

To ensure the coverage requirements are met for each antenna the link budget should becalculated. The link budget is used to calculate the minimum downlink signal strengthreceived at the mobile as well as the minimum uplink received. The inputs includereceive path diversity gain in the uplink, the possible use of mast head amplifiers and theoutput power of the mobile. Most of the information would come from the manufacturersspecifications, or be calculated for each Microcell separately.

If these differences are not taken into consideration it is possible that the BTS will have aservice area far greater than which the mobile can support due to it operating on a muchlimited output power. Therefore the path losses and output powers must be very carefullycalculated to achieve a system balance.

These factors together with the base station height can be used to calculate thecoverage area of the cell. Increasing the output power of the BTS will of course increasethe cell size, but it will mean that the mobile is maybe not capable of making a call in thenew coverage area. A solution would be to increase the gain of the antenna.

BTS/MS Tx Power

The maximum transmit power of the BTS or MS depends upon the type being used forexample:

Horizonmicro2 GSM900 1.2W 30.8dBm

Class 4 MS 2.0W 33.0dBm

The actual transmit power is set by the database parameter max_tx_bts , the value ofwhich for different radios are listed in W23. The values represent the calibrated outputpower at the top of the cabinet with one stage of combining. Therefore any furthercombining will effect the actual power output and will require calculating on an individualbasis.

Feeder loss

This will depend on the length of cable and its design specification. A figure of –3dBm isfairly typical.

BTS Antenna gain

This information is taken from manufacturers information sheets, typical value 8dBi.

Fading/Interference Margin

Losses due to multipath fading and interference. These figures are usually –3dB each.

MS/BTS Rx Sensitivity

The receiver sensitivity is defined as the minimum allowable receive signal level that willresult in a given audio quality. The reference sensitivity for a Horizonmicro2 BTS is–107dBm and the GSM reccomendation for a class 4 mobile is –102dBm. Bearing inmind this is minimum value and system noise could affect call quality an increase in thereceive threshold is often chosen as a starting design goal, especially when amplifiersare used in the design.

Antenna/Body loss

This is the loss due to the operator absorbing a portion of the electromagnetic wave. TheGSM recommendation is a loss of 3dB.

Diversity Gain

Improves uplink performance by allowing receiver to select strongest signal.

Version 1 Rev 0 Requirements for Calculating Link Budgets



7–19

Requirements for Calculating Link Budgets

sys12_ch_03_10

T

C

U

T

C

U

Combiner

Duplexer

Tx Rx

Cable

Antenna

BTS TXPower

Combiningloss

Duplexer or

Tx filter loss

Total Txpower topof rack

Feeder loss

BTSantenna

gain

MS receiversensitivity

Fading/Interferencemargin

MS antennagain/bodyloss

MStransmit

power

Antenna gain/diversitygain

Fading/Interferencemargin

Feeder loss

BTS receiversensitivity

Version 1 Rev 0Minimum Coupling Loss Considerations



7–20

Minimum Coupling Loss ConsiderationsIn any RF design where there is the possibility of mobiles operating in close proximity tothe base station antenna some consideration must be given to the minimum couplingloss. The minimum coupling loss is the propagation path loss between the base stationantenna and the nearest point where a mobile may be expected to be in operation. If theMCL and the system losses are low then there is a potential for interference from‘foreign’ mobiles using external base stations while they are located close to theantennas.

Let’s say a mobile is using the indoor system near the perimeter of the cell and is beingreceived at a low level. If a ‘foreign’ mobile is in use close to the antenna on a nearbychannel, then the interference may drown out the ‘wanted’ mobiles signal.

In most cases, the combined total path loss from the MCL and the system losses arelarge enough to prevent the foreign mobiles unwanted power from being received within9dB of the sensitivity of the TRX. If the system losses are low then the cell coveragemay be determined by the need for the ‘wanted’ signal to have an interference margin ofgreater than 9dB.

Version 1 Rev 0 Minimum Coupling Loss Considerations



7–21

Minimum Coupling loss Considerations

sys12_ch_03_11

Wanted MobileMobile fromforeign network

Minimum Coupling Loss (MCL) is the minimum distance between antenna and nearestrealistic point where a mobile can operate

The foreign mobile/microcell BTS generates wideband noise/modulation

A C/I ratio of 9dB must be maintained for the call to be maintained in the uplinkor downlink

A margin may be introduced (MCL) to counter this effect – however it will restrict thecoverage of the microcell

�

�

�

�

Version 1 Rev 0Designing with Close Proximity Mobiles



7–22

Designing with Close Proximity Mobiles

Let us take the example of a foreign mobile near the microcell antenna. The question weneed to ask is what is the receive level at the radio and is it 9dBs less than the minimumwanted receive level?

In order to work out this we need to know some information regarding the mobile:

� Foreign MS Tx power

� What is the frequency band of the foreign mobile

� How far the foreign mobiles frequency offset from the wanted mobiles.

For our example lets say the MS tx power = 33dBm , frequency offset = 400KHz andthe mobile is operating in the GSM900 frequency band.

Next we need to consider the point in the neighbourhood of this antenna where the pathloss is minimum i.e. the nearest point at which a mobile could be expected to beoperating. The point at which MCL is experienced will depend on various parameters –antenna gain, height, orientation etc. For example, for a directional antenna in a tallbuilding the MCL point may not be on the street at all but in a building opposite theantenna.

For our example the MCL = –65dBm

Modulation Spectrum drop–off with frequency Offset

Depending on how much the foreign mobile is offset from the wanted mobiles frequencya value of relative power is given (dB’s)for the given offset. So in the diagram on theopposite page our offset is 400KHz so, reading off the graph, that will give us a 60dBdrop in relative power.

Note:

Further reading on this topic can be found in GSM 05.05.

Version 1 Rev 0 Designing with Close Proximity Mobiles



7–23

Designing with Close Proximity Mobiles

sys12_ch04_12

0

10

20

30

40

50

60

70

80

Relativepower(dB)

0 200 400 600 1200 1800 3000 6000Frequency fromthe carrier

SpectrumCharacteristics(spectrum due to themodulation) GSM 05.05

GSM 900

Foreign MS Tx Power

Frequency Band Foreign MS

Frequency Offset

MCL

Version 1 Rev 0Designing with Close Proximity Mobiles Calculations



7–24

Designing with Close Proximity Mobiles CalculationsThe raw values can now be used in a link budget calculation to see what the foreignpower at the wanted radio will be.

From the previous page, the MS power level – 33dBm

Taking into consideration the 60dB drop in relative power 33 – 60 = –27dBm

Let us say that the losses at the radio are:

Feeder loss = –3dB

Duplexor + cable loss = –1 dB

Foreign MS Tx power in wanted 200KHz band –27dBm

Minimum coupling loss (MCL) –65 dB

Feeder loss –3dB

Duplexor + cable loss –1 dB

Foreign power at radio –96dBm

Min wanted rx level for 9dB C/I –87dBm

Therefore the receive level that the wanted mobile must operate on is –87dBm forinterference from the foreign mobile to be within GSM defined margins. The graph belowshows foreign MS receive levels at the radio against MCL and system losses.

sys12_ch_03_12a

Foreign MS Rx at TRX against MCL & System Losses(400Khz, MS Tx = 33dBm)

–140

–130

–120

–110

–100

–90

–80

–70

–60

–500 5 10 15 20 25 30 35 40 45

System Losses (dB)

MCL =35dB

MCL= 45dB

MCL = 55dB

MCL =65dB

MCL = 75dB

Version 1 Rev 0 Designing with Close Proximity Mobiles Calculations



7–25

Designing with Close Proximity Mobiles Calculations

T

C

U

Duplexer

Tx Rx

Cable

Antenna

Wanted MSForeign MS

Duplexer

Feeder loss = – 3dB

Duplexer/cableloss = – 1dB–

MCL = – 65dBm–

Foreign MS Tx power = – 27dBm

Wanted MS will have to bereceived at 9 dBs less thanforeign MS power – 87dBm

Foreign MS power atradio = – 96 dBm

sys12_ch_03_12

Version 1 Rev 0Uplink Budget Calculation Comparisons



7–26

Uplink Budget Calculation ComparisonsHaving calculated the minimum receive level for the wanted signal to obtain adequatecarrier to interference ratio with respect to the foreign signal, we may now calculate theallowed path loss. The wanted receive level for our example was –87dBm.

Link budget with Close Proximity Mobiles

The MS is transmitting at full power on 33dBm and the receive level taking intoconsideration is –87dBm, so the difference between the two is 120dB. However, asdiscussed previously there are other factors to be taken into consideration.

Antenna gain/body loss –3dB

BTS antenna gain 5dBi

BTS feeder loss –3dB

Duplexor/Cable loss –1dB

This leaves us with an allowed path loss for –87dBm at the radio of –118dB

Link Budget without Close proximity Mobiles

If we say the BTS sensitivity is –104dBm, if we allow a further margin of 7dB tocompensate for noise, then we come to a figure of –97dBm, so this time the differencebetween the MS and receive level is 130dB. Of course the same gains and losses applyso:




Duplexor/Cable loss –1dB

This leaves us with an allowed path loss for –97dBm at the radio of –128dB

Conclusions

If the link is designed with close proximity mobiles taken into consideration, then the pathloss figure has a 10dB difference between it and designing the link budget without closeproximity mobiles. In effect this will mean the BTS output power will have a reducedoutput power, with the implication that the effective cell size is also reduced.

Version 1 Rev 0 Uplink Budget Calculation Comparisons



7–27

Uplink Budget Calculation Comparisons

� Link Budget with Close proximity Mobiles

MS transmit power = 33 dBm

Calculated receive level = –87 dBm

Resultant link budget without losses/gains = 120 dB

Antenna gain/body loss = –3dB

BTS antenna gain = 5dBi

BTS feeder loss = –3dB

Duplexor/cable loss = –1dB

Path loss for –87 dBm at the radio is –118dB

� Link Budget without Close proximity Mobiles

BTS sensitivity with 7 dB margin for noise = –97dBm

MS transmit power = 33 dBm

Resultant link budget without losses/gains = 130 dB

Antenna gain/body loss = –3dB

BTS antenna gain = 5dBi

BTS feeder loss = –1dB

Path loss for –97dBm at the radio is –128 dB

Version 1 Rev 0Link Budget for Balanced Downlinks



7–28

Link Budget for Balanced Downlinks

Having calculated the link budget for the uplink we can now calculate the link budget forthe downlink.

Link Budget with close Proximity Working

The path loss for the uplink is 118dB. The system losses will be the same as for theuplink:




Duplexor \ Cable loss –1dB

Combiner loss –3dB

Bearing in mind that the MS receiver sensitivity for a class 4 mobile is –102dBm andallowing for a noise margin of 7dB then the design parameter we are looking for is–95dBm. Therefore BTS power output to meet these requirements is 28dBm

Link Budget without Close Proximity Working

In this case the path loss is 128dB. To meet this criteria the BTS output power wouldhave to increase by 10dB’s to 38dBm .

Version 1 Rev 0 Link Budget for Balanced Downlinks



7–29

Link Budget for Balanced Downlinks

sys12_ch_03_15

Wanted MS

Feeder loss = – 3 dB

(24dBm)

Duplexer/cable loss = – 1 dB(25dBm)

BTS Tx power at theradio = 28dBm

Receiver Sensitivity = – 95 dBm–

Body/antennaloss = 3 dB

( – 92 dBm )

Transmit power at antenna = 26dBm

Antennagain =5dB

(21dBm)

T

C

U

Duplexer

Tx Rx

Antenna

Combiner

Duplexer

Cable

Combiner loss = – 3 dB

(28dBm)

Path Loss = 118dB

Version 1 Rev 0The In–Building Solution



7–30

The In–Building Solution

Introduction to picocellular

Providing a high level of capacity and coverage inside buildings is a natural progressionfrom the macrocellular wide area coverage, through microcellular coverage of urbanenvironments to the picocellular solution that will provide coverage within buildings.

The picocellular infrastructure will provide more cost effective solutions than thetraditional BTS infrastructure due to very low output powers, as well as meeting specificenvironmental conditions.

� Macrocellular – wide area coverage, using your phone in a car.

� Microcellular – coverage of urban environments using a handportable phone.

� Picocellular – enables the concept of “cellular everyone everywhere”.

Picocellular Benefits

The picocellular environment can offer the operator the following benefits:

� low RF power providing high quality, focused indoor coverage without adverselyaffecting the surrounding network;

� picocells maximise efficient use of the available frequency spectrum enabled bythe use of low RF output power.

An effective in–building system must also provide:

� coverage at all locations where people might wish to make or receive a call;

� good call quality;

� sufficient capacity to support the number of calls to be made;

� easy capacity expansion when it is required;

� easy installation;

� minimal disruption to the external network;

Version 1 Rev 0 The In–Building Solution



7–31

Why Pico–Cellular

sys12_ch02_17

Capacity and coverage

Network maturityMobile

Pedestrian andurban

OfficesUndergrounds,Metros

Macrocells Microcells Picocells

Picocells Offer

Low RF PowerMaximise use of available FrequencySpectrum

Good indoor coverageGood call capacity

Sufficient capacity to ensure all calls

Ease of expansion

Ease of installation

Min disruption to ext network

Version 1 Rev 0In–building Coverage



7–32

In–building Coverage

In–building coverage that comes from macrocells and externally mounted microcells isdifficult to predict. This is because the main propagation paths into the building from anantenna mounted at some external location depends very much on the particularrelationship between the antenna and the building. The diagram opposite demonstratesthis.

The in–building penetration for the case of normal incidence (a) is expected to besignificantly better than for the case where the angle of incidence is shallow (b).Improved in–building coverage arising from on–street microcells is likely to be fairlyirregular, with most of the improvement in the immediate neighbourhood of the microcellantennas themselves. The situation is complicated by the dependence of in–buildingpenetration on the composition and structure of the building.

Propagation from outside to inside

� Cells deployed within streets external to the buildings being covered.

� Coverage provided both on–street and, where possible, in–building.

� Cell capacity dependent on expected subscriber usage in cell area and frequencyspectrum restrictions.

� In–building coverage dependent on building penetration requirement (directlyaffects Tx power and Rx sensitivity requirements).

Version 1 Rev 0 In–building Coverage



7–33

In–building Coverage from External Cell

sys12_ch_03_17

Antenna position

Affected building

Roadway

Antenna position

Affected building

Roadway

(a) Shallow incidence of Rx/Tx

(a) Normal incidence of Rx/Tx

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Version 1 Rev 0In–Building RF Repeaters



7–34

In–Building RF RepeatersAlso known as internal illumination. The concept here is to place a BTS either inside oroutside the building to be covered, and site a number of RF repeaters inside the building.A single carrier will feed a number of repeaters and if necessary additional carriers canbe used. Connection to the repeaters is via coaxial cable or in some cases may be fibreoptic.

The RF Repeaters (sometimes referred to as RF Heads) normally contain a low noiseamplifier, duplexer and sometimes a transmit amplifier. If there is Microcell coverageoutside the building with spare traffic capacity, a cell enhancer can be used to pick up theRF from the Micro BTS and distribute it to the in-building repeaters.

This method works well with one or two carriers however, if more capacity is required itbecomes difficult because of problems at the heads with RF intermodulation andwideband noise.

Version 1 Rev 0 In–Building RF Repeaters



7–35

In-building coverage using RF repeaters

�

��

��

��

��

� ��

��

RF repeater with cell enhancer

Indoor distribution system

(antennas & leaky feeder)

Cell enhancer

Microcell pick–up

antenna

Version 1 Rev 0Operation from Tall Buildings



7–36

Operation from Tall Buildings

A problem sometimes occurs with the uplink operation of microcellular systems whenmobiles are operating from the upper floors of tall buildings.

Consider the case as shown opposite, where a MS is being served by a nearby streetlevel microcell. The MS is operating in a building that is higher than the typicalsurrounding buildings. The downlink signal from the nearby microcell antenna is the bestserver so the MS camps on the cell and makes calls via that cell.

The problem is that due to the building height, the uplink signal is now no longerconstrained by the street canyons, and the signal will radiate uncontrollably, potentiallycausing uplink interference. The severity of such a problem depends on the mobile’sproximity to windows in the building, and on the required power level.

Potential solutions to this problem are;

1. Design the system so that in the upper floors of such typically high buildings themacrocell will be the best server.

2. Set the power control window, so that mobiles camped on a microcell in thissituation operate at lower power levels, (provided no other detrimental effects areexperienced).

3. Introduce special in–building coverage in the upper floors, so that the mobile canoperate on a special cell within the building, at lower power.

Version 1 Rev 0 Operation from Tall Buildings



7–37

Operation from Tall Buildings

sys12_ch_03_19

Serving microcellat street levelutilising streetcanyon effect

MS operating fromtall building

Design the system so upper floors are served by macro layer

Set power control lower for microcell lower to prevent excessiveradiation

Introduce in–building coverage

�

�

�

Version 1 Rev 0Antenna Types



7–38

Antenna Types

In general there are two types of antennas to choose from: omni_directional (omni) anddirectional antennas. Omni antennas provide a uniform field pattern in 360 dergrees inthe horizontal plane. Directional antennas have increased gain in one or more directionsat the expense of reducing gain in other directions.

Both directional and omni directional antennas have their uses in microcellular systems.The different antenna types can be used by the proficient cell planner to avoid shadowsreduce handover requests, and maximise traffic capture.

Directional antennas

Directional antennas are useful for covering long streets that are of a shape similar to theantenna gain pattern, giving the added advantages of extra gain in the forward directionand suppressed signal in the reverse direction this is a useful characteristic if the cell is apotential interferer to another cell located behind it.

It is also worth noting that a directional antenna could be used to improve in–buildingcoverage and reduce co–channel interference in the reverse direction.

Version 1 Rev 0 Antenna Types



7–39

Antenna Types – Directional Antennas

sys12_ch_03_20

Buildings

Coverage

In–building coverageimprovement

Antenna

Buildings

Coverage

AntennaAntenna

Reduced co–channelinterference inthis direction

Version 1 Rev 0OMNI antennas



7–40

OMNI antennas

Omni antennas are useful for covering open areas (e.g. squares, plazas). In theseareas, it is desirable to have a clear best server cell to avoid excessive handovers andtheir attendant problems.

Another application is to create a “corner crossroads” cell. This avoids having transientcells at street crossroads. The problem with transient cells is that a mobile mayhandover too (or camp on) a cell whilst it is stationary at traffic lights, and then lose thecell as it drives off at high speed before it has a chance to reselect/handover.

This situation must be avoided as even slow moving mobiles could experience problems.

The solution could be the use of an omni antenna to cover the crossroads.

However, by intersecting with more streets the potential for interference with other cellsmay be increased.

Version 1 Rev 0 OMNI antennas



7–41

OMNI Antennas

sys12_ch_03_21

Antenna

Antenna

Drop call could resultdue to transient natureof cells

Antenna

Version 1 Rev 0Installation of Microcell Antennas



7–42

Installation of Microcell Antennas

� The theoretical radiation pattern of an antenna will be distorted by mounting it inclose proximity to a wall or other structure. The antenna should ideally bemounted more than one wavelength away.

� Antennas should be mounted as far away as possible from any electricalequipment (e.g. security cameras, burglar alarms). This is because high values ofEIRP could cause triggering of the devices and contravene the standards set forthe immunity of equipment to EMC disturbances within Europe on the 1st Jan1996.

� Position of antenna and antenna azimuth should be as close as possible to thevalue used in the prediction tool.

� An external antenna should ideally be mounted at least one floor lower than thelowest roof in the cell’s coverage area in order to avoid diffraction over rooftops.Antennas should be mounted at least one floor lower than that of the oppositebuildings. Remember not to have antennas too low (at least 5 to 7m up) thisavoids obstruction by buses etc.

� Building features near the antenna (eg buttresses and corners) will have greateffects on cell shape, therefore, antenna locality should be carefully chosen.

Diversity

Due to the types of propagation and the low propagation delays in the microcellularenvironment the benefits of diversity would have to be considered on an individual basis.

Not only is space diversity (2 antennae [10 λ apart) a possible method, but also phasediversity could be used at the BTS. This system again would have to be considered on aper cell basis.

Version 1 Rev 0 Installation of Microcell Antennas



7–43

Installation of Microcell Antennas

sys12_ch04_ant

Close Proximity of wall or other structures will cause distortion

Mount antennas as far away as possible from electrical equipment

Directional antenna azimuth should be as close as possible toprediction tool

Antenna height should be situated so as not to radiate overrooftops, but not too low so tall vehicles cause interference

Building features such as buttresses and corners have a greateffect on coverage

Diversity (Motorola BTS’s do not support this feature)

Version 1 Rev 0Installation of Microcell Antennas



7–44

Microcellular Base Station ProductsMotorola manufactures a range of products specifically designed to be operated in themicrocellular environment. A brief description of each of these products is listed on thispage, however a much more in depth description of each product is contained in theappendix.

Horizon micro2This is a two–carrier base transceiver station (BTSs) that operate in the GSM900 orDCS1800 frequency bands. It can be deployed indoor or out of doors, operated over awide temperature range, and can be wall or pole mounted.

It has an Expansion feature from GSR 5.0 that allows two or three Horizon micro2 BTSunits to be connected together to effectively form a two, four or six carrier site. They areinterconnected by fibre optic cable. One BTS in the configuration acts as the master andthe other units as slaves. If the expanded feature is used a mixture of GSM900 and DCS1800 frequencies can be equipped.

RF Output Power

The Horizon micro2 GSM900 generates 1.2 W (30.8 dBm) per carrier, while theDCS1800 generates 2.0 W (33.0 dBm) per carrier.

Frequency Hopping

The Horizonmicro2 and Horizonmicro2_ext and support synthesizer frequency hopping(SFH).

Links

Options exist for sites to be interconnected by E1 or HDSL (star and daisy chain) links.

M–Cellcity & M–Cell city+This is a two–carrier base transceiver station (BTSs) that operate in the GSM900 orDCS1800 frequency bands. It can be deployed indoor or out of doors, operated over awide temperature range, and can be wall or pole mounted.

The M–Cell city+ adds High bit rate Digital Subscriber Line (HDSL) modems, and aircombining providing an improved RF output power.

RF Output Power

The M–Cellcity GSM900 generates 1.2W (30.8 dBm) per carrier, while the DCS1800generates 1W (30.0 dBm). The M–Cellcity+ GSM900 generates 2.5W, whilst theDCS1800 generates 2W.

Frequency Hopping

These products do not support frequency hopping.

Links

Options exist for sites to be interconnected by E1/T1, the M–Cellcity+ has a HDSLmodem providing the technology to connect up the network, enabling E1 or HDSLcommunication links.

Version 1 Rev 0 Installation of Microcell Antennas



7–45

Microcellular Base Station Products

ig.057.rh

SYS12_Ch4_22

Horizonmicro2

Version 1 Rev 0Antenna types for Picocellular



7–46

Antenna types for Picocellular

Both directional and omni–directional antennas have their uses within the in–buildingenvironment. The different attributes of the various antenna types can be used by thecell planner to:

� Reduce handover requests

� Maximise traffic capture

� Minimise external interference

Directional antenna

Directional antennas are useful for covering long corridors, giving the added advantagesof extra gain in the forward direction and suppressed signal in the reverse direction. Thiscan reduce co–channel interference in the reverse direction.

The building geometry will modify the directivity of any particular antenna.

� High gain (forward direction)

� Control of interference in reverse direction

� Good for covering long corridors

Omni antenna

Omni antenna are useful for covering open areas. In these areas it is desirable to have aclear best server cell to avoid excessive handovers.

Installation of antennas

� The theoretical radiation pattern of an antenna will be distorted by mounting it inclose proximity to a wall or other structure. The antenna should ideally bemounted more than one wavelength away.

� Antennas should be mounted as far away as possible from any electricalequipment, (e.g. security cameras, burglar alarms).

� Building features near the antenna will have a great effect on cell shape, thereforeantenna locality should be carefully chosen.

� Cosmetic appearance.

� Consideration of EMC.

Version 1 Rev 0 Antenna types for Picocellular



7–47

Antenna Types for Picocellular

sys12_ch_03_33

Rooms

Rooms

DirectionalAntenna

Rooms

CoverageReduced co–channelinterference in thisdirection

OMNI Antenna

Version 1 Rev 0Designing with Radiating Cable



7–48

Designing with Radiating Cable

Radiating cable or flat strip are types of cable which have holes milled in the outerconductor. This allows the RF to ‘leak’ along the length of the cable and hence offers analternative to point source antenna’s.

A small portion of the RF energy that is transmitted down the cable leaks out from theholes, hence the term ”leaky” coax.

Some of the expected advantages of radiating cable are that the coverage is moreuniform and the radiated power levels are low, which improves signal containment andreduces the risk of overloading the portable unit. Although Radiating cable can be usedmost anywhere, typical applications have been for covering long tunnels and hallways.

When designing a leaky feeder system it is important to check that the chosen cable typehas the correct fire and smoke ratings for the all the areas of installation. It isrecommended that the manufacturers mounting fixtures are included in the design toensure that the coverage pattern and coupling loss meets the specification.

Version 1 Rev 0 Designing with Radiating Cable



7–49

Designing with Radiating Cable

sys12_ch_03_34

BTS Ground Floor

First Floor

Splitter, tap or directionalcoupler

LeakyCable

Version 1 Rev 0Designing with Radiating Cable



7–50

Version 1 Rev 0



A1

Appendix A (Erlang B Tables)

Version 1 Rev 0



A2

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

�

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A3

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

� � ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� � �

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � � �

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� ��

� ��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

Version 1 Rev 0



A4

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� � ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

� ��

��

��

��

��

��

��

��

� ��

��

� � ��

��

��

� � ��

� � ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

� � ��

� ��

��

��

��

��

��

��

��

��

��

��

��

� �

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A5

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� �

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� �

�

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

� ��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

Version 1 Rev 0



A6

��

��

��

��

��

��

� �

� ��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

� � ��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� � �

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� �

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A7

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A8

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A9

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

Version 1 Rev 0



A10

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� � ��

��

� ��

� ��

��

��

��

��

��

��

��

��

� ��

��

� � ��

��

��

� � ��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

� ��

� ��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

� � �

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

� ��

� ��

� ��

��

��

��

��

� ��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� � �

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� � ��

��

� ��

��

��

��

��

��

��

� ��

��

� ��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

� ��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

Version 1 Rev 0



A11

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

� � � �

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� � ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� � � �

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A12

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � �

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

Version 1 Rev 0



A13

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A14

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

��

� ��

��

� � ��

��

��

��

��

� ��

��

��

��

��

��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� � ��

��

��

��

��

��

� ��

��

��

��

��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� � ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

� ��

Version 1 Rev 0



A15

��

��

��

��

��

��

��

��

� � ��

� ��

��

��

��

��

� ��

� ��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

� ��

��

��

��

��

� ��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

� ��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A16

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� � �

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A17

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

Version 1 Rev 0



A18

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

� ��

� ��

��

� ��

��

� � ��

��

��

��

� ��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

� ��

��

� � ��

��

��

��

��

� ��

� ��

��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� � ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� � ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

� � ��

��

��

��

��

��

��

� ��

��

��

� ��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

� ��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

��

Version 1 Rev 0



A19

Version 1 Rev 0



A20

Version 1 Rev 0



B–1

Appendix B (Hotspot Survey)

Version 1 Rev 0Hotspot Survey



B–2

Hotspot SurveyThe objective is to provide a cost-effective method of confirming the location formicrocells.

Once a search area is defined for a potential microcell site then test transmitters will beset up in the search areas.

The points at which the transmitter is sited must: –

� be practical for installation of BTS equipment

� be practical in terms of antenna mounting

� be practical in terms of acquirement, both on cost, environmental and likelihood oflease

� it should be capable of capturing identified potential traffic

The test cell is then used as a target, by neighbouring cells, for the collection of largevolumes of subscriber-generated measurement reports, using the call-trace BSS featureand then analyzed using the Call Trace Product (CTP).

The Hotspot/Neighbour Analysis facility produces a series of graphs and reports thatanalyzes neighbour data. It allows several neighbour reports to be produced summarisingneighbour information.

Version 1 Rev 0 Hotspot Survey



B–3

Hotspot Sit Equipment

Typical equipment required for Hotspot transmitter site.




B–4

Pre-requisites (local office)

Search areas have been defined based upon: –

� Neighbouring cell traffic/blocking statistics

� Potential traffic capture areas have been identified (e.g. pedestrian areas,shopping centres and business areas).

� Maps of appropriate area, are available, to approximate scale of 1:12000.

� Dummy neighbour definitions, for the test transmitters have been defined in thesurrounding cells neighbour lists.

� Microcell design requirements have been agreed with customer.

� Suitable vehicles and manpower are available.

� CTP is installed.

� Clean frequency available for hotspot sites.

� Authority is obtained from local authorities/police to conduct hotspot activity.

Equipment loaned by Swindon (less optional items)

The following equipment is required: –

Equipment Initial Cost(£)900MHz TEMS HotspotGenerator

8000

Bird Wattmeter 300Portable lightweight, sec-tioned 5metre mast

350

Pneumatic telescopic 8metre mast kit (optional)

2000

Portable mast tripod 1000dBd and 3dBd Katrein omniantennas

260

5dB directional antennaswith 65 and 120 degreebeam width (one of each)

300

10 and 20m feeder cables 150 portable generator(optional)

600

mains inverter 100charger for TEMS batteries 50Digital camera 500Compass 70

Total Cost 12780




B–5

Initial deployment

It is proposed that an engineer from Swindon will travel to a certain country, with therequired test equipment, for up to a maximum of two weeks.

He will be responsible for training the local office in hotspot work for the microcellulartrial/rollout.

He will work with the local office engineers, in reviewing the pre-planning work,deployment of the hotspot transmitter and analysis of the CTP data so that the localoffice is capable of providing hotspot work, as cost effective sold service to the customer.

Post initial deployment

The TEMS transmitter and ancillaries necessary for the hotspot work will be rented to thelocal office for the microcell trial period until the local office can source their ownequipment.

Practical deployment of hotspot survey

1. Identify hotspot test transmitter sites from

– high traffic/blocking macro cells

– Identifed areas under cells identified above, which, will potentially relievetraffic from macro layer

– areas likely to generate high mobile microcell usage (e.g. pedestrian areas,office areas)

– Areas required to maintain contiiguous microcell layer or to link areas of hightraffic

– Buildings of strategic importance

2. As many test transmitters as possible should be deployed to ensure the bestpossible comparison, of potential microcell sites, simultaneously thus removing theuncertainty and inaccuracy incurred with different sample periods.

3. The duration of the data collection will depend on the traffic levels on thesurrounding cells,

4. The test transmitter will require mains power to maintain continuous RF output ,from the TEMS transmitter, over extended periods. This can be supplied by a 12vdriven, car mounted, mains inverter or a separate portable mains generator(normal ring mains supply is often unavailable in test locations).

For security, the test site should not be unattended and thus a vehicle should beused to transport equipment, provide power for the test transmitter and provide asecure location for the equipment.

An alternative to the lightweight mast would be to use a 5–8metre pneumatic mastattached to the vehicle, (a van would provide a suitable platform). This wouldspeed up the mast erection process but would prevent access to some siteswhere vehicular access is restricted.




B–6

5. Test–neighbour insertion, in all macro cell’s neighbour lists likely to providecoverage to test transmitter hotspot sites . The basic is not defined in testneighbours. When test transmitters are set up at different locations then thetransmitter can be set with a different bsic so that CTP can differentiate betweenthe two sites during post-processing.

Normal neighbour syntax

add_neighbor <src_gsm_cell_id or “src_cell_name ”> <neighbor_gsm_cell_id><placement> [<list_type>]

Test neighbour syntax

add_neighbor <src_gsm_cell_id or “src_cell_name”> <test> <num> <placement>[<list_type>]

Note :

The string test <num> may be entered for this field where <num> is a value from 1 to64. This permits test neighbours to be added to the BA_SACCH and/or BA_BCCH lists.When a test neighbour is added, the value entered in the placement field will be ignoredand the frequency will be the only prompted parameter.

6. Trace-call should be enabled on all cells surrounding the test site(s) but careshould be taken to prevent overloading of resources.

GPROC loading can be assessed from the raw stat ”cpu_usage ”, over a number ofdays, real-time monitoring can be achieved via RAM EMON – see Note 1

The trace-call data has a relatively low priority, in BSS link terms, to prevent thepotential loss of data, the following should be considered:

GPROC loading (LCF, BSP, OML)

Data collection:

Data type

No. of MRs range 1––255(1=all MRs)

No. of simultaneous calls per LCF max 4

No. of cells/sites per LCF as config. In database

Trace-call (nth call/IMSI/SCCP) range 1––255(1=all calls)

Note1. : to monitor GPROC loading

– remote login to GPROC, set Executive Monitor mode –

<set_mmi exec_mon >

– monitor GPROC loading, every half second, with command

<perf> < ENTER>

– Exit from RAM EMON mode with command

<set_mmi cust_mmi >

– alternatively check loading with ”ps” command within

RAM EMON




B–7

CTP analysis

The data analysis will vary dependant on the type of microcell and the reason for themicrocell implementation.

<< to be continued>>

ANNEXE

Guidelines for using 1500 Call Trace

The user should be aware that care must be taken when using call trace. If an excessiveamount of trace data is requested by the user, the BSS and OMC performance willdegrade and some trace data will be discarded in order to preserve system integrity.

Worst case scenario – “full data”:

The heaviest burden is placed on the network when the user specifies “all” data types, ameasurement report interval of 1, and 16 simultaneous calls traced per LCF. Wetherefore recommend that the following guidelines not be exceeded when requesting

“full data” (that is, “all” data with measurement report interval=1):

Max. # of calls simultaneously traced at the OMC <= 8

Max. # of calls simultaneously traced per BSS* <= 4

Max. # of calls simultaneously traced per MMI TTY <= 2

Note : This limit must be enforced by the user, since the “Maximum simultaneous callstraced per LCF” limit specified during trace creation is the limit per LCF, and a BSC willtypically contain several LCFs.

Other factors:

The user is advised to avoid sending trace data to the OMC when other significant OMLactivities, such as uploads and downloads, are occuring. A high call load on the BSS willalso adversely affect call trace performance.




B–8

Tracing more calls

In general, users may trace a larger number of calls simultaneously by limiting theamount of data requested for each call.

For example:

For a moderately loaded (2500 cph, 10 sec hold time) single LCF system, the followingcriteria would not normally result in loss of trace data:

Measurement Report Interval = 10

Data Types: all

Nth call interval = 1

Max. simultaneous calls per LCF = 8

Note, however, if the number of calls traced simultaneously were increased to 16, andthe load increased to 4000cph, 12 sec hold time, data would start to be lost at around the13th call.

Tips:

1. Specify only the data types that you need. RSS data produces the most output.Abis data can also produce a lot of data, particularly during call creation, handover,and completion.

2. Use the “Total number of calls to be traced” field to limit the total amount of datacollected.

3. When specifying RSS (measurement report) data, choose a Measurement ReportInterval greater than 1 (the default is 10).

4. For “Nth call” traces, specify a large number for N (e.g. 50).

5. For “Nth call” traces, specify a small number for the maximum number of tracesper LCF (e.g. 2).

6. Trace on a particular mobile, subscriber or call whenever possible.

7. Use the “trace_disp ” MMI command to monitor the number of calls being traced.

8. Trace outside of peak call periods if possible.

9. Stop or reduce tracing when performing code/database uploads and downloads.

10. Delete unwanted trace logs from the OMC. A cron task periodically deletes oldlogs. However heavy call trace usage may necessitate more frequent attention.




B–9




B–10

Version 1 Rev 0



C–1

Appendix C (In-Building

Requirements Questionnaire)

Version 1 Rev 0In-Building Requirements Questionnaire



C–2

In-Building Requirements QuestionnaireThe following questionnaire should be given to the operator/customer as soon asthe location has been selected for an in-building system. The informationobtained can then be used as a foundation for discussion of the systemrequirements. Building plans should be used to indicate the location of anyrequested information.

Operator:

Customer:

General Information:

1. Which of the following criteria define the requirements of this system:

a) Equipment trialb) Improve on poor cellular coverage levelsc) Provide high capacity for in-building usersd) In-building mobile calls originating on this system must be

maximizede) To replace the existing PABX systemf) Other – please specify

2. Are there any deadlines for installation/optimization which have to be met?

3. Can building plans be supplied in both paper and electronic formats?

Capacity – If possible, a sample of PABX and existing macrostatistics should be used to determine the estimated traffic loadingof the in-building system.

1. How many mobile users are expected to use this system?

2. What is the expected growth of the system?

Version 1 Rev 0 In-Building Requirements Questionnaire



C–3

3. Estimate the average busy hour figure in Erlangs per user?

4. Where the high capacity solution is required:

i) estimate peak traffic for each grouping of users

ii) estimate time of peak busy hour for each group.

5. Identify areas which are expected to have high capacity requirements.

6. Identify the type of users (job description) in each area.

7. What is the required target blocking probability?

Coverage

1. Identify all areas of the building(s) requiring coverage.

2. Are there any key areas which are particularly important from a coverage point ofview?

3. Identify all entrances and exits , including to and from parking areas.




C–4

4. Is coverage required in any lifts/stairwells? Specify.

5. Describe the general structure of the building. Indicate:

– internal/external wall materials; brickwork, glass, partition walls

– if glass is used, is it metallic/tinted?

– floor layout - open plan or enclosed rooms?

– is there an atrium or other building feature which may require specialconsideration?

– number of floors in the building – are all floors required to have in-buildingcoverage?

Installation

1. Is there a suitable location to install the in-building system BTS (210 by 72 by41cm)?

2. Is –48V (27V) available in this location? (Additional space for a power supply maybe needed).

3. Are there existing 2Mbit links to the external network? (Indicate location orproposed location).

4. Do leased lines exist between PABX and Cellular Operators Switching Platform?

5. What capacity is available on these links?




C–5

6. Will this system be configured as a co-located BSC or connected to an existingBSC?

7. Are there are restrictions on mounting silent RF units of 33 x 15 x 11cm and 10kgin weight within the building?

8. Are there any positions where there would be difficulty in supplying mains power(110V/220V/240V) for the above units?

9. Are there any restrictions on using coax to feed distributed antenna?

10. Can any cabling be routed through false ceilings?

11. Does the building have an existing fibre optic or twisted pair backbone which couldbe used to connect the RF units to the cluster controller? (Attach cablespecification if available).Note: HDSL links require twisted pairs without any electronic switching

12. Identify the location of patch panels where this system can be connected to.(Indicate the type of connectors used).

13. Are there limitations on access times for measurements, installation oroptimisation?




C–6

14. Are there any common/public areas in the building where instalklation would beprohibited?

15. Are there any specific equipment types you wish to use or avoid in this site?

Network Operator/RF Environment

1. Which frequency spectrum will be used, and how many frequencies will beavailable? (Identify specific frequencies if possible).

2. What is the signal level inside the building perimeter from the existing macroNetwork?

3. Identify the location of the surrounding macro sites on a map. Indicate cell name,BCCH/TCH carrier frequencies, BSICs, antenna orientations and output powerlevels.

4. How much tolerance is there towards mobiles external to the building originatingon the in-building system?

5. How near are other buildings containing picocell systems?




C–7




C–8

Version 1 Rev 0 Planning the In–Building Solution



C–9

Planning the In–Building Solution

Planning the in–building solution

When considering the picocellular solution, certain factors have to be taken into account.

The flow chart opposite highlights certain functions that will enable the identification ofthe requirements needed to oversee the picocellular installation.

Also contained in the Appendices is:

� In–Building Requirements Questionnaire

This questionnaire, when completed, will enable assessment of the customerrequirements and should be sent prior to visiting the customer. The questionnaire formsthe basis for initial discussions and will focus the customer to provide the informationrequired.

Let us consider each of the functions:

Version 1 Rev 0Planning the In–Building Solution



C–10

Send ”In–building requirementquestionnaire”

Talk to Customer

Initial Planning

Visit Site

Modify Plan

Agree Final Plan with Customer

Order and Install Equipment

Test and Optimise

Run and Maintain

Version 1 Rev 0 Talk to the customer



C–11

Talk to the customer

Determine predicted traffic levels

Each BTS can offer a determined traffic capacity in Erlangs, which is dependent on thegrade of service offered. Questions have to be asked to determine the required trafficlevels from each of the users and an initial estimate of the position of those users withinthe building.

If the traffic levels are not known, then useful estimates are:

� 100mE per ’Heavy’ user

� 30mE per ’Average’ user

� 10mE per ’Light’ user

Answers to these questions can also be resolved by use of:

� Current mobile billing information

� Number of incoming calls

� Existing PABX call records

� Identify geographically located groups by types of employment/mobile usage.

Determine Coverage Requirements

The primary goal for most systems will be excellent coverage. However, the greater thearea, and the higher the probability of coverage within that area, the higher the cost ofthe final system. With this in mind, it will be useful to get rankings of importance ofdifferent areas within the building. This will aid decisions later on in the process.

Obtain Building Plans

These are required for planning the system. The more detail, the better, and in bothpaper and electronic format.

Obtain Contact Name for Building Cable

Installation of the system will need help from the in–building cable expert.

Version 1 Rev 0Talk to the customer



C–12

Talk to the Customer

Determine Predicted Traffic Levels


Get Building plans

Get Contact Name for Building Cabling

Get Surrounding Cell Information

Ask for Statistics to be Enabled on Surrounding Cells

sys12_ch04_25

Version 1 Rev 0 Talk to the customer



C–13


The cellular operator should provide the details of the surrounding cells. This wouldnormally be in the form of a map and a .CEL file, indicating:

� RF unit positions

� Antenna Orientation

� BSIC

� Cell ID

� Carrier Frequencies

� O/P Power Levels

Other cell–related information (e.g. rxlev_access_min would also be useful).

Ask for Statistics to be enabled on Surrounding Cells

Traffic loads and interference levels (dropped calls and poor RXQUAL) are goodindicators of a system performance. Knowledge of this before and after installation of thein–building system will help in diagnosing any problems that may occur later on. (A threeweek period may be necessary to give a valid statistical benchmark).

Version 1 Rev 0Talk to the customer



C–14

Talk to the Customer

Determine Predicted Traffic Levels


Get Building plans

Get Contact Name for Building Cabling


Ask for Statistics to be Enabled on Surrounding Cells

sys12_ch04_25

Version 1 Rev 0 Initial planning



C–15

Initial planningCoverage prediction needs two inputs:

� Path loss from the picocell RF units

� Minimum acceptable level for users

Mark High Traffic Areas

Used to determine the RF distribution in a given area where traffic is a limiting factor. Todetermine this it is imperative that the peak hour is identified for the specific areas as itmay differ. If congestion relief is likely to be employed a check must be undertaken tosee that adjacent cells do not incurr the same peak hours/traffic loading.

Use Simple Coverage Rules to estimate Coverage

With application of the simple planning rules, and the knowledge of the minimum requiredsignal levels, estimates of the cell radii can be made.

Mark Potential Head Positions on Plan

With the cell radius and traffic levels, initial estimates on the number of heads and theirrelative positions can be made.

When selecting a potential Picocell RF Unit location, several factors should beconsidered:

� Key Areas and VIP locations

In an ideal implementation, all areas of the building would have excellent coverage.Providing such a system may prove to be costly and inefficient so establishing some sortof weighting could be important.

� Interference from the macro/micro network will not be constant around theperimeter of the building. To meet the required C/I levels the Picocell RF Unitsmay need to favour one area of the building.

� RF Leakage from the in–building system should be kept to a minimum.

� In areas of projected high traffic, coincide overlap of coverage from individual cellsso that congestion relief/directed retry can be enabled.

The method for assessing the suitability of these locations is to set up a test transmitteron a clean frequency and record the downlink signal strength throughout that floor.

Check Traffic Coverage is Adequate

Re–address coverage requirements ensuring they meet the criteria defined.

Find Space for the BTS

The PBX room would be an ideal position. This may already contain a power source, airconditioning and provide access to the core MDF.

Suggest Cable Runs

Once the position of the RF distribution and the BTS are known, cable runs have to beplanned.

Version 1 Rev 0Initial planning



C–16

Initial Planning

Analyse outside levels to determirequired levels on the internal syst

Mark high traffic areas

Use simple coverage rules to estimate c

Mark potential RF distribution on p

Check traffic coverage is adequa

Find space for BTS

Suggest cable runs

sys12_ch04_26

Version 1 Rev 0 Visit site



C–17

Visit site

Ensure RF Unit Site is Suitable

The planned site should be checked for suitability. Theoretically, it should be a flatsurface, large and strong enough to support the Picocell RF Unit. Positions of nearbypower, telephony and alarm cabling should be checked to ensure no accidents occurwhile drilling the mounting holes. Care should be taken to minimise environmentalimpact.

Check Coverage from Suggested Head Sites

In the initial planning of a system, a test transmitter and measurement receiver can beused to check the RF levels that can be achieved from the proposed sites. Thetransmitter can be placed at the proposed site, ensuring the antenna is mounted on astand to get the correct proposed height. The coverage area can then be tested bymeasuring the signal levels.

Check Cable Runs with Site Expert

Go through plans with the building expert. Check that the proposed cable runs are freefrom potential interference from other telecommunication or electrical services and do notpass through electronic switching elements.

Version 1 Rev 0Visit site



C–18

Visit Site

Ensure RF unit site is suitable

Check coverage from suggested RDistribution

Take surveys on surrounding cell siteand on suggested frequencies

Check cable runs with site expert

sys12_ch04_27

Version 1 Rev 0 Modify plan



C–19

Modify plan

Analyze Outside Signal Levels

All surveys are processed to help determine the frequency plan and coveragerequirements. If a specific set of frequencies have not been allocated to the in–buildingsystem, or macro/micro signals need identifying, a scan of the surrounding network canidentify a list of potential candidates. The TEMS frequency scanning tool can be used tomeasure the signal strength of all GSM frequencies in a particular location. As themobile is only guaranteed to see BCCH carriers, the BSIC of each frequency should berequested. A map of the surrounding cells can then be used to identify associated trafficchannels.

As the received signal strength will not remain constant around the building, the scanshould be carried out at each of the extremities of the building. It is normally best tomake these measurements on the upper floor, as well as intermediate floors, of abuilding as these are most open to interference. The scan should also be repeatedseveral times at each location to provide a level of confidence, as well as coincide withpeak busy hours.

It is important to get close to the windows in perimeter offices as this is where the lowestC/I is expected. If a TCH frequency from a surrounding macro is re–used on thein–building system the associated BCCH must be scanned to determine worst caseinterference.

Determine Actual Coverage

Combining the measured path loss data and the analysed external signal levels willproduce an excellent coverage prediction. This should be compared with the initialrequirement to check that all important areas exceed the expectation.

Move RF Distribution if Necessary

For coverage, traffic or interconnect reasons the RF distribution may need to bereplanned. This will result in at least a number of extra tasks and repeating a number ofchecks.

Draw Up Frequency Plan

Generate Neighbour List

Version 1 Rev 0Modify plan



C–20

Modify Plan

Analyse outside signal levels

Determine actual coverage

Move RF distribution positionsif necessary

Draw up frequency plan

Generate neighbour list

sys12_ch04_28

Version 1 Rev 0 Agree final plan with customer



C–21

Agree final plan with customer

Revisit Customer

Agree Final Plan

It is imperative that the following points are discussed with the customer:

� Network architecture to fulfill the requirements

� Final hardware requirements

� Responsibilities

� Resourcing

� Acceptance criteria. This should be defined in terms of:

– Coverage

– Quality

– Call drop

– Call setup (originations)

– Call setup (failures)

– Handover failures

Version 1 Rev 0Agree final plan with customer



C–22

Agree Final Plan with Customer

Revisit customer

Agree final plan

sys12_ch04_29

Version 1 Rev 0 Order and install equipment



C–23

Order and install equipmentThe flow diagram opposite shows the functional steps and requirements for ordering andinstallation of the proposed solution.

Version 1 Rev 0Order and install equipment



C–24

Order and Install Equipment

Order MotorolaEquipment

InstallRF Distribution

InstallBTS

Configure in –buildingcabling

Order E1 lineinstallation

Order AuxEquipment

Fit antennand coa

InstallDC power

supply

sys12_ch04_30

Version 1 Rev 0 Test and optimize



C–25

Test and optimizeThe flow diagram opposite shows the functional steps and possible requirements for thetesting and optimisation of the solution.

The optimization process can be divided into three phases:

Phase 1

� Database configuration

� Neighbour list creation

� Algorithm selections

� Idle Mode

� Handover Strategy

Phase 2

In order to minimise disruption to cellular service quality in the building, as muchoptimisation as possible will be performed before commercial users are allowed toaccess the system. This will be achieved by setting the Cell_bar_access_switch , butretaining the ability to handover. Optimization will be performed with TEMS mobilesconfigured to ignore Cell_bar_access .

The picocells, at this stage, should be included in the neighbour lists of the externalmacrocells, but configured with maximum ho_margins in order to exclude the hand in ofcommercial mobiles.

Tests will include:

� coverage testing

– individual floors – lock onto cell under test and disable HO

– key offices

– all stairwells

� interference testing

– frequency re–use within the building (NB. floors 1 & 4)

– external macro frequencies

� handover testing

– floor to floor

– HO to macros at perimeter

– HO to macros at all exits

Version 1 Rev 0Test and optimize



C–26

Test and Optimize

Power up system

Activate cell_bar

Coverage handover tests

Call testing

Connect to commercial system

Check internal to external handovers and originations

Remove cell_bar

Monitor OMC to ensure all equipment is in–service and no ala

Customer sign–off against acceptance criteria

sys12_ch04_31

Version 1 Rev 0 Test and optimize



C–27

Tests will include:

� idle mode operation testing

– stairwells and areas of possible interference

� enable call trace to examine all cells for path balance

This also gives a breakdown of handover causes, BSSMAP and DTAP message countswhich are useful in assessing the system traffic character.

� enable per neighbour cell stats for handover cause analysis.

This will readily identify cells performance and effectiveness of the selected handoverstrategy.

� handover testing

– HO from macros at perimeter

– HO from macros at all entrances

� Full system testing for coverage acceptance.

As a result of the above tests, frequencies, cells power and handover parameters can beadjusted to meet the acceptance criteria.

The system call performance should be established with all the picocells set to thecorrect handover margins in the neighbour lists of the external macrocells in order toallow full testing of the hand in process.

Phase 3

After this phase is completed successfully, Cell_bar_access may be lifted and fullcommercial service may begin. Further coverage and interference testing will berequired to address any issues, in the commercial environment, not carried out in earlierphases. Additionally, some system monitoring will be required to evaluate theeffectiveness of the inbuilding system deployment.

A subscriber fault reporting process should be put in place so that any faults may beisolated quickly.

Once the picocell system has enough subscribers to generate reliable statistics, then areduced statistical collection should be used for daily system assessment.

Version 1 Rev 0Test and optimize



C–28

Test and Optimize

Power up system

Activate cell_bar

Coverage handover tests

Call testing

Connect to commercial system

Check internal to external handovers and originations

Remove cell_bar

Monitor OMC to ensure all equipment is in–service and no alarms

Customer sign–off against acceptance criteria

sys12_ch04_31

Version 1 Rev 0 Run and maintain



C–29

Run and maintainThe flow diagram opposite shows the functional steps and requirements for ensuring thatthe installed solution operates effectively and efficiently, as well as monitoring forpotential failings.

Version 1 Rev 0Run and maintain



C–30

Run and Maintain

Check stats to ensure system iscarrying traffic

Monitor OMC

Frequency re–plan if exterior system is re–planned

Expand system if it starts to block

sys12_ch04_32



i

Answers

Version 1 Rev 0



ii

Version 1 Rev 0



7–i

C2 Reselection ExerciseThe parameters and levels specified on the facing page are typical values experiencedby a mobile in the reselection process. Use these values to determine whether themobile will reselect to the neighbour cell. The mobile has been in the server well overone hour, and the best neighbour has been in the top six measured cells for exactly 4minutes.

��

�� 1*,&%)# */. � "%,-.�

�� !�� ,2'!0�� !--�(%)� ��

��

�� ! �� (-�.2+1,�(�2� $� � ��

��

��

��

��

�� !�� ,2'!0�� !--�(%)� ��

��

�� ! �� (-�.2+1,�(�2� $� ��

��

��

��

��

� �-!,0!,� � �)!%#$�*/,� � !''�,!-!'! .�$3-.!,!-%-

� -!,0!, �� !%#$�*/, �� !%#$�*/, � !''�,!-!'! .�$3-.!,%-%- �∴ �* ,!-!'! .%*)

Version 1 Rev 0



7–ii

Version 1 Rev 0



7–iii

Version 1 Rev 0



7–iv

Power Budget Exercise part 1The figures specified on the facing page can be used by the HDPC to calculate thePower budget assessment. Use the working area to calculate PBBT (n).

�� *"$.,�

/%.2(+&� *(+ �*/!04-3.!*"4�� 4)%2!�� !�!�

/%.2(+&� � ��

/%.2(+&� ��

�� *($.,�

+%(&'#,1.� *(+ �*/!04-3.!*"4�+�� !�� +�

+%(&'#,1.� � ��

+%(&'#,1.� ��

�� +�� /%.2(+& � �%(&'#,1.

�� +��

�� +��

Power Budget Exercise part 2If ms_twpwr_max_cell in add_neigh of the server was set to 27 dBm then theoutcome of the calculation for PBGT(n) would be 9. It could be lowered to 25 dBm to getan even greater effect.

This has helped make the microcell neighbor look more attractive.

Version 1 Rev 0



7–v

Version 1 Rev 0



7–vi

Answers (possible solution)

add_neighbor



Placement External

list type Both

pgsm

20

0 to 63 – All sites could have a separate BSIC

33 dBm – Class 4 2w mobiles

6 (-104dBm) – Not restricting (note on street level) – criteria 1

6 – Set low for easy emergency qualification but prevent

ping ponging

4 – Reasonably quick and accurate for emergency handup

0 –Disable interference avoidance test

2 – Macrocell (no PBGT(n)) qualification

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

_ _ _ _ –

Version 1 Rev 0



7–vii


add_neighbor



Placement Internal – Same BSC as SRC cell

list type BA_SACCH – Discourages idle selection or reselection

0No synchronised handovers (separate BTSs)

30 (–80 dBm) – On street level plus a margin

6 – Low for easy qualification but prevent ping ponging

6 – Fast handin encouraged

0 –Disable interference avoidance test

4 – Alg type for line of sight neighbor

(For type 4) 24 –20 SACCH multiframes is approximately 10 seconds

forces fast mobiles upto the macro layer.

add_cell parameters neighbor 2 (frequency used = 43)

frequency_type – PGSM

BSIC = (0 to 63)

max_tx_ms = 27

rxlev_min_ def = 30

Version 1 Rev 0



7–viii

Answers (possible solution)add_neighbor



Placement Internal – Same BSC as SRCELL

list type BA_SACCH – Discourages idle selection or reselection

0

30 (–80dBm) –On street level plus a margin

6 – Low ho_margin used as handin encouraged for slow MS but prevents ping ponging

8 – Longer hreqave to ensure co–channel interference

neighbour is clear

0 – Disable interefence avoidance test

7 – Alg type for line of sight neighbor

9 –ho_margin 3dB higher than ho_margin(n)



BSIC = (0 to 63)

max_tx_ms = 27

rxlev_min_ def = 30

Version 1 Rev 0



7–ix


add_neighbor



Placement Internal

list type BOTH –

0

30 (–80dbm) – On street level plus a margin

6 – Low ho_margin as handin encouraged for slow MS and

prevents ping ponging

4 – Fast handin required

0 – Disable interference avoidance test

3 – Alg type (round the corner neighbour)

(For type 3) 30 – (–80db) levels drop by typically –20db

(For type 3) 30 – (–80db) levels drop by typically –20db

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _



BSIC = (0 to 63)

max_tx_ms = 27

rxlev_min_ def = 30

Version 1 Rev 0



7–x


add_neighbor



Placement Internal – Same BSC as source cell

list type BOTH –

0

25 – (–85dbM) Should stop external handing in (–25db)

3 – Low ho_margin as handover would have to be quick

going into the building also prevents ping ponging

3 – Fast handin required

0 – Disable int avoidance test

6– In–building neighbour – other types also should beconsidered

(For type 6) 20 – delay time approx 10s

(For type 6) 4 –

To discourage on street hand–in

(For type 6) 2 –To encourage hand–in for those entering building.

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _

_ _ _ _



BSIC = (0 to 63)

max_tx_ms = 27

rxlev_min_ def = 25

Version 1 Rev 0



7–xi

10TH JULY 95Manual Title Goes Here


G–1

Glossary of technical terms andabbreviations



G–2

Numbers



G–1

Numbers# Number.

2 Mbit/s link As used in this manual set, the term applies to the European4-wire 2.048 Mbit/s digital line or link which can carry 30A-law PCM channels or 120 16 kbit/s GSM channels.

4GL 4th Generation Language.

A



G–2

AA interface Interface between MSC and BSS.

A3 Authentication algorithm that produces SRES, using RANDand Ki.

A38 A single algorithm performing the function of A3 and A8.

A5 Stream cipher algorithm, residing on an MS, that producesciphertext out of plaintext, using Kc.

A8 Ciphering key generating algorithm that produces Kc usingRAND and Ki.

AB Access Burst.

Abis interface Interface between a remote BSC and BTS. Motorola offers aGSM standard and a unique Motorola Abis interface. TheMotorola interface reduces the amount of message traffic andthus the number of 2 Mbit/s lines required between BSC andBTS.

ABR Answer Bid Ratio.

ac–dc PSM AC–DC Power Supply module.

ac Alternating Current.

AC Access Class (C0 to C15).

AC Application Context.

ACC Automatic Congestion Control.

ACCH Associated Control CHannel.

ACK, Ack ACKnowledgement.

ACM Accumulated Call meter.

ACM Address Complete Message.

ACPIM AC Power Interface Module. Used in M-Cell6 indor ac BTSequipment.

AC PSM AC Power Supply Module. Used in M-Cell6 BTS equipment.

ACSE Associated Control Service Element.

ACU Antenna Combining Unit.

A/D Analogue to Digital (converter).

ADC ADministration Centre.

ADC Analogue to Digital Converter.

ADCCP ADvanced Communications Control Protocol.

ADM ADMinistration processor.

ADMIN ADMINistration.

ADN Abbreviated Dialling Number.

ADPCM Adaptive Differential Pulse Code Modulation.

AE Application Entity.

AEC Accoustic Echo Control.

AEF Additional Elementary Functions.

A



G–3

AET Active Events Table. Alarms and events are sent to theEvents Log in the GUI. Different operators will have differentsubscription lists. All alarms and events are sent to the AETbefore they are re-routed to different subscription lists.

AFC Automatic Frequency Control.

AFN Absolute Frame Number.

AGC Automatic Gain Control.

AGCH Access Grant CHannel. A GSM common control channelused to assign MS to a SDCCH or a TCH.

Ai Action indicator.

AI Artificial Intelligence.

AIB Alarm Interface Board.

AIO A class of processor.

Air interface The radio link between the BTS and the MS.

AM Amplitude Modulation.

AMA Automatic Message Accounting (processor).

AM/MP Cell broadcast mobile terminated message. A messagebroadcast to all MSs in a cell.

AoC Advice of Change.

AoCC Advice of Change Charging supplementary service.

AoCI Advice of Change Information supplementary service.

AOC Automatic Output Control.

AP Application Process.

ARFCN Absolute Radio Frequency Channel Number. An integerwhich defines the absolute RF channel number.

ARQ Automatic ReQuest for retransmission.

ARP Address Resolution Protocol.

ASCE Association Control Service Element. An ASE whichprovides an AP with the means to establish and control anassociation with an AP in a remote NE. Maps directly ontothe Presentation layer (OMC).

ASE Application Service Element (OMC)

ASE Application Specific Entity (TCAP).

ASN.1 Abstract Syntax Notation One.

ASP Alarm and Status Panel.

ASR Answer Seizure Ratio.

ATB All Trunks Busy.

ATI Antenna Transceiver Interface.

ATT (flag) ATTach.

ATTS Automatic Trunk Testing Subsystem.

AU Access Unit.

AuC Authentication Centre. A GSM network entity which providesthe functionality for verifying the identity of an MS whenrequested by the system. Often a part of the HLR.

A



G–4

AUT(H) AUThentication.

AUTO AUTOmatic mode.

B



G–5

B

B Interface Interface between MSC and VLR.

BA BCCH Allocation. The radio frequency channels allocated in acell for BCCH transmission.

BAIC Barring of All Incoming Calls supplementary service.

BAOC Barring of All Outgoing Calls supplementary service.

BBBX Battery Backup Board.

BBH Base Band Hopping.

BCC BTS Colour Code.

BCCH Broadcast Control CHannel. A GSM control channel used tobroadcast general information about a BTS site on a per cellor sector basis.

BCD Binary Coded Decimal.

BCF Base station Control Function. The GSM term for the digitalcontrol circuitry which controls the BTS. In Motorola cell sitesthis is a normally a BCU which includes DRI modules and islocated in the BTS cabinet.

BCIE Bearer Capability Information Element.

BCU Base station Control Unit. A functional entity of the BSSwhich provides the base control function at a BTS site. Theterm no longer applies to a type of shelf (see BSC and BSU).

BCUP Base Controller Unit Power.

BER Bit Error Rate. A measure of signal quality in the GSMsystem.

BES Business Exchange Services.

BFI Bad Frame Indication.

BHCA Busy Hour Call Attempt.

BI all Barring of All Incoming call supplementary service.

BIB Balanced-line Interconnect Board. Provides interface to 12balanced (6-pair) 120 ohm (37-pin D-type connector) lines for2 Mbit/s circuits (See also T43).

BIC–Roam Barring of All Incoming Calls when Roaming outside theHome PLMN Country supplementary service.

BIM Balanced-line Interconnect Module.

Bin An area in a data array used to store information.

BL BootLoad. Also known as download. For example, databasesand software can be downloaded to the NEs from the BSS.

BLLNG BiLLiNG.

bit/s Bits per second (bps).

Bm Full rate traffic channel.

BN Bit Number. Number which identifies the position of aparticular bit period within a timeslot.

BPF Bandpass Filter.

BPSM �BCU Power Supply Module.

B



G–6

BS Basic Service (group).

BS Bearer Service. A type of telecommunication service thatprovides the capability for the transmission of signalsbetween user-network interfaces. The PLMN connection typeused to support a bearer service may be identical to that usedto support other types of telecommunication service.

BSC Base Station Controller. A network component in the GSMPLMN which has the digital control function of controlling allBTSs. The BSC can be located within a single BTS cabinet(forming a BSS) but is more often located remotely andcontrols several BTSs (see BCF, BCU, and BSU).

BSG Basic Service Group.

BSIC Base Transceiver Station Identity Code. A block of code,consisting of the GSM PLMN colour code and a base stationcolour code. One Base Station can have several BaseStation Colour Codes.

BSIC-NCELL BSIC of an adjacent cell.

BSP Base Site control Processor (at BSC).

BSN Backward Sequence Number.

BSS Base Station System. The system of base station equipment(Transceivers, controllers and so on) which is viewed by theMSC through a single interface as defined by the GSM 08series of recommendations, as being the entity responsiblefor communicating with MSs in a certain area. The radioequipment of a BSS may cover one or more cells. A BSSmay consist of one or more base stations. If an internalinterface is implemented according to the GSM 08.5x seriesof recommendations, then the BSS consists of one BSC andseveral BTSs.

BSSAP BSS Application Part (of Signalling System No. 7) (DTAP +BSSMAP).

BSSC Base Station System Control cabinet. The cabinet whichhouses one or two BSU shelves at a BSC or one or two RXUshelves at a remote transcoder.

BSSMAP Base Station System Management Application Part (6-8).

BSSOMAP BSS Operation and Maintenance Application Part (ofSignalling System No. 7).

BSU Base Station Unit shelf. The shelf which houses the digitalcontrol modules for the BTS (p/o BTS cabinet) or BSC (p/oBSSC cabinet).

BT British Telecom.

BT Bus Terminator.

BTC Bus Terminator Card.

BTF Base Transceiver Function.

BTP Base Transceiver Processor (at BTS). One of the six basictask groups within the GPROC.

B



G–7

BTS Base Transceiver Station. A network component in the GSMPLMN which serves one cell, and is controlled by a BSC.The BTS contains one or more Transceivers (TRXs).

Burst A period of modulated carrier less than one timeslot. Thephysical content of a timeslot.

C



G–8

CC Conditional.

C Interface Interface between MSC and HLR/AUC.

C7 ITU-TSS Signalling System 7 (sometimes referred to as S7 orSS#7).

CA Cell Allocation. The radio frequency channels allocated to aparticular cell.

CA Central Authority.

CAB Cabinet.

CADM Country ADMinistration. The Motorola procedure used withinDataGen to create new country and network files in theDataGen database.

CAI Charge Advice Information.

CAT Cell Analysis Tool.

CB Cell Broadcast.

CB Circuit Breaker.

CBC Cell Broadcast Centre.

CBCH Cell Broadcast CHannel.

CBF Combining Bandpass Filter.

CBL Cell Broadcast Link.

CBM Circuit Breaker Module.

CBMI Cell Broadcast Message Identifier.

CBSMS Cell Broadcast Short Message Service.

CBUS Clock Bus.

CC Connection Confirm (Part of SCCP network connectivity).

CC Country Code.

CC Call Control.

CCB Cavity Combining Block, a three way RF combiner. Thereare two types of CCB, CCB (Output) and CCB (Extension).These, with up to two CCB Control cards, may comprise theTATI. The second card may be used for redundancy.

CCBS Completion of Calls to Busy Subscriber supplementaryservice.

CCCH Common Control CHannels. A class of GSM controlchannels used to control paging and grant access. IncludesAGCH, PCH, and RACH.

CCCH_GROUP Group of MSs in idle mode.

CCD Common Channel Distributor.

CCDSP Channel Coding Digital Signal Processor.

CCF Conditional Call Forwarding.

CCH Control CHannel. Control channels are channels which carrysystem management messages.

CCH Council for Communications Harmonization (referred to inGSM Recommendations).

C



G–9

CCIT Comité Consultatif International Télégraphique etTéléphonique. This term has been superceded by ITU–TSS(International Telecommunications Union –Telecommunications Sector).

CCM Current Call Meter.

CCP Capability/Configuration Parameter.

CCPE Control Channel Protocol Entity.

CCS Hundred call-seconds. The unit in which amounts oftelephone traffic are measured. A single call lasting onehundred seconds is one CCS. See also erlang.

Cct Circuit.

CDB Control Driver Board.

CDE Common Desktop Environment. Part of the SUN software(crontab – cron job file).

CDR Call Detail Records.

CDUR Chargeable DURation.

CEB Control Equalizer Board (BTS).

CED Called station identifier.

CEIR Central Equipment Identity Register.

Cell By GSM definition, a cell is an RF coverage area. At anomni-site, cell is synonymous with site; at a sectored site, cellis synonymous with sector. This differs from analoguesystems where cell is taken to mean the same thing as site.(See below).

Omni Site1-Cell Site

(1 BTS)

6-Sector Siteor

6-Cell Site(6 BTSs)

1 Cell =1 Sector

CEND End of charge point.

CEPT Conférence des administrations Européennes des Postes etTelecommunications.

CERM Circuit Error Rate Monitor.

CF Conversion Facility.

CF all Call Forwarding services.

CFB Call Forwarding on mobile subscriber Busy supplementaryservice.

CFC Conditional Call Forward.

CFNRc Call Forwarding on mobile subscriber Not Reachablesupplementary service.

CFNRy Call Forwarding on No Reply supplementary service.

C



G–10

CFU Call Forwarding Unconditional supplementary service.

Channel A means of one-way transmission. A defined sequence ofperiods (for example, timeslots) in a TDMA system; a definedfrequency band in an FDMA system; a defined sequence ofperiods and frequency bands in a frequency hopped system.

CIM Coaxial Interconnect Module.

CHP CHarging Point.

CHV Card Holder Verification information.

CKSN Ciphering Key Sequence Number.

CI Cell Identity. A block of code which identifies a cell within alocation area.

CI CUG Index.

CIC Circuit Identity Code.

CIR, C/I Carrier to Interference Ratio.

Ciphertext Unintelligible data produced through the use of encipherment.

CKSN Ciphering Key Sequence Number.

CLI Calling Line Identity.

CLIP Calling Line Identification Presentation supplementaryservice.

CLIR Calling Line Identification Restriction supplementary service.

CLK Clock.

CLKX Clock Extender half size board. The fibre optic link thatdistributes GCLK to boards in system (p/o BSS etc).

CLM Connectionless Manager.

CLR CLeaR.

CM Configuration Management. An OMC application.

CM Connection Management.

CMD CoMmanD.

CMM Channel Mode Modify.

CMIP Common Management Information Protocol.

CMISE Common Management Information Service Element. An ASEwhich provides a means to transfer management informationvia CMIP messages with another NE over an associationestablished by ASCE using ROSE (OMC).

CMR Cellular Manual Revision.

CNG CalliNg tone.

COLI COnnected Line Identity.

Collocated Placed together; two or more items together in the sameplace.

Coincident Cell A cell which has a co-located neighbour whose cell boundaryfollows the boundary of the said cell. The coincident cell hasa different frequency type, but the same BSIC, as that of theneighbour cell.

COLP COnnected Line Identification Presentation supplementaryservice.

C



G–11

COLR COnnected Line Identification Restriction supplementaryservice.

CODEX Manufacturer’s name for a type of multiplexer and packetswitch commonly installed at the Motorola OMC-R.

COM Code Object Manager.

COM COMplete.

COMB Combiner.

CONNACK CONNect ACKnowledgement.

COMM, Comms COMMunications.

CommsLink Communications Link. (2Mbit/s)

CONF CONFerence circuit.

CONFIG CONFIGuration Control Program.

CP Call Processing.

CPU Central Processing Unit.

C/R Command/Response field bit.

CR Carriage Return (RETURN).

CR Connection Request (Part of SCCP network connectivity).

CRC Cyclic Redundancy Check (3 bit).

CRE Call RE-establishment procedure.

CREF Connection REFused (Part of SCCP network connectivity).

CRM Cell Resource Manager.

CRM-LS/HS Cellular Radio Modem-Low Speed/High Speed. Low speedmodem used to interwork 300 to 2400 bit/s data servicesunder V.22bis, V.23, or V.21 standards. High speed modemused to interwork 1200 to 9600 bit/s data services underV.22bis, V.32, or V.29/V.27ter/V.21 standards.

CRT Cathode Ray Tube (video display terminal).

CSFP Code Storage Facility Processor (at BSC and BTS).

CSP Central Statistics Process. The statistics process in the BSC.

CSPDN Circuit Switched Public Data Network.

CT Call Transfer supplementary service.

CT Channel Tester.

CT Channel Type.

CTP Call Trace Product (Tool).

CTR Common Technical Regulation.

CTS Clear to Send. Method of flow control (RS232 Interface).

CTU Compact Transceiver Unit (M-Cellhorizon radio).

CUG Closed User Group supplementary service.

Cumulative value The total value for an entire statistical interval.

CW Call Waiting supplementary service.

D



G–12

D

D Interface Interface between VLR and HLR.

D/A Digital to Analogue (converter).

DAB Disribution Alarm Board.

DAC Digital to Analogue Converter.

DACS Digital Access Cross-connect System.

DAN Digital ANnouncer (for recorded announcements on MSC).

DAS Data Acquisition System.

DAT Digital Audio Tape.

DataGen Sysgen Builder System. A Motorola offline BSS binary objectconfiguration tool.

dB Decibel. A unit of power ratio measurement.

DB DataBase.

DB Dummy Burst (see Dummy burst).

DBA DataBase Administration/Database Administrator.

DBMS DataBase Management System.

dc Direct Current.

DCB Diversity Control Board (p/o DRCU).

DCCH Dedicated Control CHannel. A class of GSM controlchannels used to set up calls and report measurements.Includes SDCCH, FACCH, and SACCH.

DCD Data Carrier Detect signal.

DCE Data Circuit terminating Equipment.

DCF Data Communications Function.

DCF Duplexed Combining bandpass Filter. (Used inHorizonmacro).

DCN Data Communications Network. A DCN connects NetworkElements with internal mediation functions or mediationdevices to the Operations Systems.

DC PSM DC Power Supply Module.

DCS1800 Digital Cellular System at 1800 MHz. A cellular phonenetwork using digital techniques similar to those used in GSM900, but operating on frequencies of 1710 – 1785 MHz and1805 – 1880 MHz.

DDF Dual-stage Duplexed combining Filter. (Used inHorizonmacro).

DDS DataGen Directory Structure.

DDS Data Drive Storage.

DDS Direct Digital Synthesis.

DEQB Diversity Equalizer Board.

DET DETach.

DFE Decision Feedback Equalizer.

DGT Data Gathering Tool.

D



G–13

DHP Digital Host Processor.

DIA Drum Intercept Announcer.

DINO E1/HDSL Line termination module.

DINO T1 Line termination module.

DISC DISConnect.

Discon Discontiuous.

DIQ Diversity In phase and Quadrature phase.

DIR Device Interface Routine.

DL Data Link (layer).

DLCI Data Link Connection Identifier.

DLD Data Link Discriminator.

DLNB Diversity Low Noise Block.

DLSP Data Link Service Process.

DLSP Digital Link Signalling Processor.

Dm Control channel (ISDN terminology applied to mobile service).

DMA Deferred Maintenance Alarm. An alarm report level; animmediate or deferred response is required (see also PMA).

DMA Direct Memory Access.

DMR Digital Mobile Radio.

DMX Distributed Electronic Mobile Exchange (Motorola’snetworked EMX family).

DN Directory Number.

DNIC Data network identifier.

Downlink Physical link from the BTS towards the MS (BTS transmits,MS receives).

DP Dial/Dialled Pulse.

DPC Destination Point Code. A part of the label in a signallingmessage that uniquely identifies, in a signalling network, the(signalling) destination point of the message.

DPC Digital Processing and Control board.

DPNSS Digital Private Network Signalling System (BT standard forPABX interface).

DPP Dual Path Preselector.

DPR, DPRAM Dual Port Random Access Memory.

DPSM Digital Power Supply Module.

DRAM Dynamic Random Access Memory.

DRC Data Rate Converter board. Provides data and protocolconversion between PLMN and destination network for 8circuits (p/o IWF).

DRCU Diversity Radio Channel Unit. Contains transceiver, digitalcontrol circuits, and power supply (p/o BSS) (see RCU).

(D)RCU Generic term for radio channel unit. May be standard RCU ordiversity radio channel unit DRCU.

D



G–14

DRI Digital Radio Interface. Provides encoding/decoding andencryption/decryption for radio channel (p/o BSS).

DRIM Digital Radio Interface extended Memory. A DRI with extramemory.

DRIX DRI Extender half size board. Fibre optic link from DRI toBCU (p/o BSS).

DRX, DRx Discontinuous reception (mechanism). A means of savingbattery power (for example in hand-portable units) byperiodically and automatically switching the MS receiver onand off.

DS-2 German term for 2 Mbit/s line (PCM interface).

DSE Data Switching Exchange.

DSI Digital Speech Interpolation.

DSP Digital Signal Processor.

DSS1 Digital Subscriber Signalling No 1.

DSSI Diversity Signal Strength Indication.

DTAP Direct Transfer Application Part (6-8).

DTE Data Terminal Equipment.

DTF Digital Trunk Frame.

DT1 DaTa form 1 (Part of SCCP network connectivity).

DTI Digital Trunk Interface.

DTMF Dual Tone Multi-Frequency (tone signalling type).

DTR Data Terminal Ready signal. Method of flow control (RS232Interface).

DTRX Dual Transceiver Module. (Radio used in M-Cellarena andM-Cellarenamacro).

DTX, DTx Discontinuous Transmission (mechanism). A means ofsaving battery power (for example in hand-portable units) andreducing interference by automatically switching thetransmitter off when no speech or data are to be sent.

Dummy burst A period of carrier less than one timeslot whose modulation isa defined sequence that carries no useful information. Adummy burst fills a timeslot with an RF signal when noinformation is to be delivered to a channel.

DYNET DYnamic NETwork. Used to specify BTSs sharing dynamicresources.

E



G–15

E

E See Erlang.

E Interface Interface between MSC and MSC.

EA External Alarms.

EAS External Alarm System.

Eb/No Energy per Bit/Noise floor.

EBCG Elementary Basic Service Group.

EC Echo Canceller. Performs echo suppression for all voicecircuits.

ECB Provides echo cancelling for telephone trunks for 30 channels(EC).

ECID The Motorola European Cellular Infrastructure Division.

ECM Error Correction Mode (facsimile).

Ec/No Ratio of energy per modulating bit to the noise spectraldensity.

ECT Event Counting Tool.

ECT Explicit Call Transfer supplementary service.

EEL Electric Echo Loss.

EEPROM Electrically Erasable Programmable Read Only Memory.

EGSM900 Extended GSM900.

EI Events Interface. Part of the OMC-R GUI.

EIR Equipment Identity Register.

EIRP Effective Isotropic Radiated Power.

EIRP Equipment Identity Register Procedure.

EL Echo Loss.

EM Event Management. An OMC application.

EMC ElectroMagnetic Compatibility.

EMF Electro Motive Force.

EMI Electro Magnetic Interference.

eMLPP enhanced Multi-Level Precedence and Pre-emption service.

EMMI Electrical Man Machine Interface.

EMU Exchange office Management Unit (p/o Horizonoffice)

EMX Electronic Mobile Exchange (Motorola’s MSC family).

en bloc Fr. — all at once (a CCITT #7 Digital Transmission scheme);En bloc sending means that digits are sent from one systemto another ~ (that is, all the digits for a given call are sent atthe same time as a group). ~ sending is the opposite ofoverlap sending. A system using ~ sending will wait until ithas collected all the digits for a given call before it attempts tosend digits to the next system. All the digits are then sent asa group.

EOT End of Tape.

EPROM Erasable Programmable Read Only Memory.

E



G–16

EPSM Enhanced Power Supply Module (+27 V).

EQB Equalizer Board. Control circuit for equalization for 8 timeslots each with equalizing circuitry and a DSP (p/o RCU).

EQCP Equalizer Control Processor.

EQ DSP Equalizer Digitizer Signal Processor.

Erlang International (dimensionless) unit of traffic intensity defined asthe ratio of time a facility is occupied to the time it is availablefor occupancy. One erlang is equal to 36 CCS. In the USthis is also known as a traffic unit (TU).

ERP Ear Reference Point.

ERP Effective Radiated Power.

ERR ERRor.

ESP Electro-static Point.

ESQL Embedded SQL (Structured Query Language). An RDBMSprogramming interface language.

E-TACS Extended TACS (analogue cellular system, extended).

Ethernet Type of Local Area Network.

ETR ETSI Technical Report.

ETS European Telecommunication Standard.

ETSI European Telecommunications Standards Institute.

ETX End of Transmission.

EXEC Executive Process.

F



G–17

F

F Interface Interface between MSC and EIR.

FA Fax Adaptor.

FA Full Allocation.

FA Functional Area.

FAC Final Assembly Code.

FACCH Fast Associated Control Channel. A GSM dedicated controlchannel which is associated with a TCH and carries controlinformation after a call is set up (see SDCCH).

FACCH/F Fast Associated Control Channel/Full rate.

FACCH/H Fast Associated Control Channel/Half rate.

FB Frequency correction Burst (see Frequency correction burst).

FC-AL Fibre Channel Arbitration Loop. (Type of hard disc).

FCCH Frequency Correction CHannel. A GSM broadcast controlchannel which carries information for frequency correction ofthe mobile (MS).

FCP Fault Collection Process (in BTS).

FCS Frame Check Sequence.

FDM Frequency Division Multiplex.

FDMA Frequency Division Multiple Access.

FDN Fixed Dialling Number.

FDP Fault Diagnostic Procedure.

FEC Forward Error Correction.

FEP Front End Processor.

FER Frame Erasure Ratio.

FFS, FS For Further Study.

FH Frequency Hopping.

FIB Forward Indicator Bit.

FIR Finite Impulse Response (filter type).

FK Foreign Key. A database column attribute; the foreign keyindicates an index into another table.

FM Fault Management (at OMC).

FM Frequency Modulation.

FMIC Fault Management Initiated Clear.

FMUX Fibre optic MUltipleXer.

FN Frame Number. Identifies the position of a particular TDMAframe within a hyperframe.

FOA First Office Application.

FOX Fibre Optic eXtender.

FR Full Rate. Refers to the current capacity of a data channel onthe GSM air interface, that is, 8 simultaneous calls per carrier(see also HR – Half Rate).

F



G–18

FRU Field Replaceable Unit.

Frequency correction Period of RF carrier less than one timeslot whose modulationbit stream allows frequency correction to be performed easilywithin an MS burst.

FS Frequency Synchronization.

FSL Free Space Loss. The decrease in the strength of a radiosignal as it travels between a transmitter and receiver. TheFSL is a function of the frequency of the radio signal and thedistance the radio signal has travelled from the point source.

FSN Forward Sequence Number.

FTAM File Transfer, Access, and Management. An ASE whichprovides a means to transfer information from file to file(OMC).

ftn forwarded-to number.

FTP Fault Translation Process (in BTS).

FTP File Transfer Protocol.

G



G–19

GG Interface Interface between VLR and VLR.

Gateway MSC An MSC that provides an entry point into the GSM PLMNfrom another network or service. A gateway MSC is also aninterrogating node for incoming PLMN calls.

GB, Gbyte Gigabyte.

GBIC Gigabit Interface Converter.

GCLK Generic Clock board. System clock source, one per site (p/oBSS, BTS, BSC, IWF, RXCDR).

GCR Group Call Register.

GDP Generic DSP Processor board. Interchangeable with the XCDRboard.

GDP E1 GDP board configured for E1 link usage.

GDP T1 GDP board configured for T1 link usage.

GHz Giga-Hertz (109).

GID Group ID. A unique number used by the system to identify auser’s primary group.

GMB GSM Multiplexer Board (p/o BSC).

GMR GSM Manual Revision.

GMSC Gateway Mobile-services Switching Centre (see GatewayMSC).

GMSK Gaussian Minimum Shift Keying. The modulation techniqueused in GSM.

GND GrouND.

GOS Grade of Service.

GPA GSM PLMN Area.

GPC General Protocol Converter.

GPROC Generic Processor board. GSM generic processor board: a68030 with 4 to 16 Mb RAM (p/o BSS, BTS, BSC, IWF,RXCDR).

GPROC2 Generic Processor board. GSM generic processor board: a68040 with 32 Mb RAM (p/o BSS, BTS, BSC, IWF, RXCDR).

GPRS General Packet Radio Service.

GPS Global Positioning by Satellite.

GSA GSM Service Area. The area in which an MS can be reachedby a fixed subscriber, without the subscriber’s knowledge ofthe location of the MS. A GSA may include the areas servedby several GSM PLMNs.

GSA GSM System Area. The group of GSM PLMN areasaccessible by GSM MSs.

GSM Groupe Spécial Mobile (the committee).

GSM Global System for Mobile communications (the system).

GSM MS GSM Mobile Station.

GSM PLMN GSM Public Land Mobile Network.

G



G–20

GSR GSM Software Release.

GT Global Title.

GTE Generic Table Editor. The Motorola procedure which allowsusers to display and edit MCDF input files.

Guard period Period at the beginning and end of timeslot during which MStransmission is attenuated.

GUI Graphical User Interface.

GUI client A computer used to display a GUI from an OMC-R GUIapplication which is beingbrun on a GUI server.

GUI server A computer used to serve the OMC-R GUI applicationprocess running locally (on its processor) to other computers(Gui clients or other MMI processors).

GWY GateWaY (MSC/LR) interface to PSTN.

H



G–21

HH Interface Interface between HLR and AUC.

H-M Human-Machine Terminals.

HAD, HAP HLR Authentication Distributor.

HANDO, Handover HANDOver. The action of switching a call in progress fromone radio channel to another radio channel. Handover allowsestablished calls to continue by switching them to anotherradio resource, as when an MS moves from one BTS area toanother. Handovers may take place between the followingGSM entities: timeslot, RF carrier, cell, BTS, BSS and MSC.

HCU Hybrid Combining Unit. (Used in Horizonmacro).

HDLC High level Data Link Control.

HDSL High bit-rate Digital Subscriber Line.

HLC High Layer Compatibility. The HLC can carry informationdefining the higher layer characteristics of a teleservice activeon the terminal.

HLR Home Location Register. The LR where the current locationand all subscriber parameters of an MS are permanentlystored.

HMS Heat Management System. The system that providesenvironmental control of the components inside the ExCell,TopCell and M-Cell cabinets.

HO HandOver. (see HANDO above).

HPU Hand Portable Unit.

HOLD Call hold supplementary service.

HPLMN Home PLMN.

HR Half Rate. Refers to a type of data channel that will doublethe current GSM air interface capacity to 16 simultaneouscalls per carrier (see also FR – Full Rate).

HS HandSet.

HSI/S High Speed Interface card.

HSM HLR Subscriber Management.

HSN Hopping Sequence Number.

HU Home Units.

HW Hardware.

Hyperframe 2048 superframes. The longest recurrent time period of theframe structure.

I



G–22

I

I Information frames (RLP).

IA Incomming Access (closed user group (CUG) SS(supplementary service)).

IA5 International Alphanumeric 5.

IADU Integrated Antenna Distribution Unit. (The IADU is theequivalent of the Receive Matrix used on pre-M-Cell BTSs).

IAM Initial Address Message.

IAS Internal Alarm System.

IC Integrated Circuit.

IC Interlock Code (CUG SS).

IC(pref) Interlock Code op the preferential CUG.

ICB Incoming Calls Barred.

ICC Integrated Circuit(s) Card.

ICM In-Call Modification.

ICMP Internet Control Message Protocol.

ID, Id IDentification/IDentity/IDentifier.

IDN Integrated Digital Network.

IDS INFOMIX Database Server. (OMC-R relational databasemanagement system).

IE Information Element (signalling).

IEC International Electrotechnical Commission.

IEEE Institute of Electrical and Electronic Engineers.

IEI Information Element Identifier.

I-ETS Interim European Telecommunication Standard.

IF Intermediate Frequency.

IFAM Initial and Final Address Message.

IM InterModulation.

IMACS Intelligent Monitor And Control System.

IMEI International Mobile station Equipment Identity. Electronicserial number that uniquely identifies the MS as a piece orassembly of equipment. The IMEI is sent by the MS alongwith request for service.

IMM IMMediate assignment message.

IMSI International Mobile Subscriber Identity. Published mobilenumber (prior to ISDN) (see also MSISDN) that uniquelyidentifies the subscription. It can serve as a key to derivesubscriber information such as directory number(s) from theHLR.

IN Intelligent Network.

IN Interrogating Node. A switching node that interrogates anHLR, to route a call for an MS to the visited MSC.

INS IN Service.

I



G–23

INS Intelligent Network Service.

InterAlg Interference Algorithm. A single interference algorithm in acell.

Interworking The general term used to describe the inter-operation ofnetworks, services, supplementary services and so on. Seealso IWF.

Interval A recording period of time in which a statistic is pegged.

Interval expiry The end of an interval.

I/O Input/Output.

IOS Intelligent Optimization Platform.

IP Initialisation Process.

IP Internet Protocol.

IPC Inter-Process Communication.

IP, INP INtermodulation Products.

IPR Intellectual PRoperty.

IPSM Integrated Power Supply Module (–48 V).

IPX (A hardware component).

ISAM Indexed Sequential Access Method.

ISC International Switching Centre.

ISDN Integrated Services Digital Network. An integrated servicesnetwork that provides digital connections betweenuser-network interfaces.

ISG Motorola Information Systems group (formally CODEX).

ISO International Organisation for Standardization.

ISQL Informix Structured Query Language.

ISUP ISDN User Part (of signalling system No. 7).

IT Inactivity Test (Part of SCCP network connectivity).

ITC Information Transfer Capability.

ITU International Telecommunication Union.

ITU–TSS International Telecommunication Union – TelecommunicationsSector.

IWF InterWorking Function. A network functional entity whichprovides network interworking, service interworking,supplementary service interworking or signalling interworking.It may be a part of one or more logical or physical entities in aGSM PLMN.

IWMSC InterWorking MSC.

IWU InterWorking Unit.

K



G–24

Kk kilo (103).

k Windows size.

K Constraint length of the convolutional code.

KAIO Kernal Asynchronous Input/Output.

kb, kbit kilo-bit.

kbit/s, kbps kilo-bits per second.

kbyte kilobyte.

Kc Ciphering key. A sequence of symbols that controls theoperation of encipherment and decipherment.

kHz kilo-Hertz (103).

Ki Individual subscriber authentication Key (p/o authenticationprocess of AUC).

KIO A class of processor.

KSW Kiloport SWitch board. TDM timeslot interchanger to connectcalls (p/o BSS).

KSWX KSW Expander half size board. Fibre optic distribution ofTDM bus (p/o BSS).

kW kilo-Watt.

L



G–25

LL1 Layer 1.

L2ML Layer 2 Management Link.

L2R Layer 2 Relay function. A function of an MS and IWF thatadapts a user’s known layer2 protocol LAPB onto RLP fortransmission between the MT and IWF.

L2R BOP L2R Bit Orientated Protocol.

L2R COP L2R Character Orientated Protocol.

L3 Layer 3.

LA Location Area. An area in which an MS may move freelywithout updating the location register. An LA may compriseone or several base station areas.

LAC Location Area Code.

LAI Location Area Identity. The information indicating the locationarea in which a cell is located.

LAN Local Area Network.

LANX LAN Extender half size board. Fibre optic distribution of LANto/from other cabinets (p/o BSS etc).

LAPB Link Access Protocol Balanced (of ITU–TSS Rec. x.25).

LAPD Link Access Protocol Data.

LAPDm Link Access Protocol on the Dm channel.

LC Inductor Capacitor (type of filter).

LCF Link Control Function.

LCN Local Communications Network.

LCP Link Control Processor.

LE Local Exchange.

LED Light Emitting Diode.

LF Line Feed.

LI Length Indicator.

LI Line Identity.

LLC Lower Layer Compatibility. The LLC can carry informationdefining the lower layer characteristics of the terminal.

Lm Traffic channel with capacity lower than a Bm.

LMP LAN Monitor Process.

LMS Least Mean Square.

LMSI Local Mobile Station Identity. A unique identity temporarilyallocated to visiting mobile subscribers in order to speed upthe search for subscriber data in the VLR, when the MSRNallocation is done on a per cell basis.

LMT Local Maintenance Terminal.

LNA Low Noise Amplifier.

LND Last Number Dialled.

L



G–26

Location area An area in which a mobile station may move freely withoutupdating the location register. A location area may compriseone or several base station areas.

LPC Linear Predictive Code.

LPLMN Local PLMN.

LR Location Register. The GSM functional unit where MSlocation information is stored. The HLR and VLR are locationregisters.

LSSU Link Stations Signalling Unit (Part of MTP transport system).

LSTR Listener Side Tone Rating.

LTA Long Term Average. The value required in a BTS’s GCLKfrequency register to produce a 16.384 MHz clock.

LTE Local Terminal Emulator.

LTP Long Term Predictive.

LTU Line Terminating Unit.

LU Local Units.

LU Location Update.

LV Length and Value.

M



G–27

MM Mandatory.

M Mega (106).

M-Cell Motorola Cell.

M&TS Maintenance and Troubleshooting. Functional area ofNetwork Management software which (1) collects anddisplays alarms, (2) collects and displays Software/Hardwareerrors, and (3) activates test diagnostics at the NEs (OMC).

MA Mobile Allocation. The radio frequency channels allocated toan MS for use in its frequency hopping sequence.

MAC Medium Access Control.

MACN Mobile Allocation Channel Number.

Macrocell A cell in which the base station antenna is generally mountedaway from buildings or above rooftop level.

MAF Mobile Additional Function.

MAH Mobile Access Hunting supplementary service.

MAI Mobile Allocation Index.

MAIDT Mean Accumulated Intrinsic Down Time.

MAINT MAINTenance.

MAIO Mobile Allocation Index Offset.

MAP Mobile Application Part (of signalling system No. 7). Theinter-networking signalling between MSCs and LRs and EIRs.

MAPP Mobile Application Part Processor.

MB, Mbyte Megabyte.

Mbit/s Megabits per second.

MCAP Motorola Cellular Advanced Processor.

MCC Mobile Country Code.

MCDF Motorola Customer Data Format used by DataGen for simpledata entry and retrieval.

MCI Malicious Call Identification supplementary service.

MCSC Motorola Customer Support Centre.

MCU Main Control Unit for M-Cell2/6. Also referred to as the MicroControl Unit in software.

MCUF Main Control Unit, with dual FMUX. (Used in M-Cellhorizon).

MCU-m Main Control Unit for M-Cell Micro sites (M-Cellm). Alsoreferred to as the Micro Control Unit in software.

MCUm The software subtype representation of the Field ReplaceableUnit (FRU) for the MCU-m.

MD Mediation Device.

MDL (mobile) Management (entity) - Data Link (layer).

ME Maintenance Entity (GSM Rec. 12.00).

M



G–28

ME Mobile Equipment. Equipment intended to access a set ofGSM PLMN and/or DCS telecommunication services, butwhich does not contain subscriber related information.Services may be accessed while the equipment, capable ofsurface movement within the GSM system area, is in motionor during halts at unspecified points.

MEF Maintenance Entity Function (GSM Rec. 12.00).

MF MultiFrame.

MF Multi-Frequency (tone signalling type).

MF MultiFunction block.

MGMT, mgmt Management.

MGR Manager.

MHS Message Handling System.

MHS Mobile Handling Service.

MHz Mega-Hertz (106).

MI Maintenance Information.

MIB Management Information Base. A Motorola OMC-Rdatabase. There is a CM MIB and an EM MIB.

MIC Mobile Interface Controller.

Microcell A cell in which the base station antenna is generally mountedbelow rooftop level. Radio wave propagation is by diffractionand scattering around buildings, the main propagation iswithin street canyons.

min minute(s).

�s micro-second (10–6).

�BCU Micro Base Control Unit.

MIT Management Information Tree. Name of a file on theMotorola OMC-R.

MM Man Machine.

MM Mobility Management.

MME Mobile Management Entity.

MMF Middle Man Funnel process.

MMI Man Machine Interface. The method in which the userinterfaces with the software to request a function or changeparameters.

MMI client A machine configured to use the OMC-R software from anMMI server.

MMI processor MMI client/MMI server.

MMI server A computer which has its own local copy of the OMC-Rsoftware. It can run the OMC-R software for MMI clients tomount.

MML Man Machine Language. The tool of MMI.

MMS Multiple Serial Interface Link. (see also 2Mbit/s link)

MNC Mobile Network Code.

MNT MaiNTenance.

M



G–29

MO Mobile Originated.

MO/PP Mobile Originated Point-to-Point messages.

MOMAP Motorola OMAP.

MoU Memorandum of Understanding.

MPC Multi Personal Computer (was p/o OMC).

MPH (mobile) Management (entity) - PHysical (layer) [primitive].

MPTY MultiParTY (Multi ParTY) supplementary service.

MPX MultiPleXed.

MRC Micro Radio Control Unit.

MRN Mobile Roaming Number.

MRP Mouth Reference Point.

MS Mobile Station. The GSM subscriber unit.

MSC Mobile-services Switching Centre, Mobile Switching Centre.

MSCM Mobile Station Class Mark.

MSCU Mobile Station Control Unit.

msec millisecond (.001 second).

MSI Multiple Serial Interface board. Intelligent interface to two2 Mbit/s digital links (see 2 Mbit/s link and DS-2) (p/o BSS).

MSIN Mobile Station Identification Number.

MSISDN Mobile Station International ISDN Number. Published mobilenumber (see also IMSI). Uniquely defines the mobile stationas an ISDN terminal. It consists of three parts: the CountryCode (CC), the National Destination Code (NDC) and theSubscriber Number (SN).

MSRN Mobile Station Roaming Number. A number assigned by theMSC to service and track a visiting subscriber.

MSU Message Signal Unit (Part of MTP transport system). Asignal unit containing a service information octet and asignalling information field which is retransmitted by thesignalling link control, if it is received in error.

MT Mobile Terminated. Describes a call or short messagedestined for an MS.

MT (0, 1, 2) Mobile Termination. The part of the MS which terminates theradio transmission to and from the network and adaptsterminal equipment (TE) capabilities to those of the radiotransmission. MT0 is mobile termination with no support forterminal, MT1 is mobile termination with support for an S-typeinterface and MT2 is mobile termination with support for anR-type interface.

MTM Mobile-To-Mobile (call).

MTP Message Transfer Part.

MT/PP Mobile Terminated Point-to-Point messages.

MTBF Mean Time Between Failures.

MTK Message Transfer LinK.

MTL MTP Transport Layer Link (A interface).

M



G–30

MTP Message Transfer Part.

MTTR Mean Time To Repair.

Multiframe Two types of multiframe are defined in the system: a26-frame multiframe with a period of 120 ms and a 51-framemultiframe with a period of 3060/13 ms.

MU Mark Up.

MUMS Multi User Mobile Station.

MUX Multiplexer.

N



G–31

NN/W Network.

NB Normal Burst (see Normal burst).

NBIN A parameter in the hoping sequence.

NCC Network (PLMN) Colour Code.

NCELL Neighbouring (of current serving) Cell.

NCH Notification CHannel.

ND No Duplicates. A database column attribute meaning thecolumn contains unique values (used only with indexedcolumns).

NDC National Destination Code.

NDUB Network Determined User Busy.

NE Network Element (Network Entity).

NEF Network Element Function block.

NET Norme Européennes de Telecommunications.

NETPlan Frequency planning tool.

NF Network Function.

NFS Network File System.

NHA Network Health Analyst. Optional OMC-R processor feature.

NIC Network Interface Card.

NIC Network Independent Clocking.

NIS Network Information Service. It allows centralised control ofnetwork information for example hostnames, IP addressesand passwords.

NIU Network Interface Unit.

NIU-m Network Interface Unit, micro.

NLK Network LinK processor(s).

Nm Newton metres.

NM Network Management (manager). NM is all activities whichcontrol, monitor and record the use and the performance ofresources of a telecommunications network in order toprovide telecommunication services to customers/users at acertain level of quality.

NMASE Network Management Application Service Element.

NMC Network Management Centre. The NMC node of the GSMTMN provides global and centralised GSM PLMN monitoringand control, by being at the top of the TMN hierarchy andlinked to subordinate OMC nodes.

NMSI National Mobile Station Identification number.

NMT Nordic Mobile Telephone system.

NN No Nulls. A database column attribute meaning the columnmust contain a value in all rows.

Normal burst A period of modulated carrier less than a timeslot.

NPI Number Plan Identifier.

N



G–32

NRZ Non Return to Zero.

NSAP Network Service Access Point.

NSP Network Service Provider.

NSS Network Status Summary.

NT Network Termination.

NT Non Transparent.

NTAAB New Type Approval Advisory Board.

NUA Network User Access.

NUI Network User Identification.

NUP National User Part (of signalling system No. 7).

NV NonVolatile.

NVRAM Non-Volatile Random Access Memory.

nW Nano-Watt (10–9).

O



G–33

O

O Optional.

OA Outgoing Access (CUG SS).

O&M Operations and Maintenance.

OASCU Off-Air-Call-Set-Up. The procedure in which atelecommunication connection is being established whilst theRF link between the MS and the BTS is not occupied.

OCB Outgoing Calls Barred within the CUG.

OCXO Oversized Voltage Controlled Crystal Oscillator.

OD Optional for operators to implement for their aim.

OFL % OverFlow.

offline IDS shutdown state.

online IDS normal operatng state.

OIC Operator Initiated Clear.

OLM Off_Line MIB. A Motorola DataGen database, used to modifyand carry out Radio Frequency planning on multiple BSSbinary files.

OLR Overall Loudness Rating.

OMAP Operations and Maintenance Application Part (of signallingsystem No. 7) (was OAMP).

OMC Operations and Maintenance Centre. The OMC node of theGSM TMN provides dynamic O&M monitoring and control ofthe PLMN nodes operating in the geographical areacontrolled by the specific OMC.

OMC-G Operations and Maintenance Centre — Gateway Part.(Iridium)

OMC-G Operations and Maintenance Centre — GPRS Part.

OMC-R Operations and Maintenance Centre — Radio Part.

OMC-S Operations and Maintenance Centre — Switch Part.

OMF Operations and Maintenance Function (at BSC).

OML Operations and Maintenance Link.

OMP Operation and Maintenance Processor.

OMS Operation and Maintenance System (BSC–OMC).

OMSS Operation and Maintenance SubSystem.

OOS Out Of Service.

OPC Originating Point Code. A part of the label in a signallingmessage that uniquely identifies, in a signalling network, the(signalling) origination point of the message.

ORAC Olympus Radio Architecture Chipset.

OS Operating System.

OSI Open Systems Interconnection.

OSI RM OSI Reference Model.

OSF Operation Systems Function block.

O



G–34

OSF/MOTIF Open Software Foundation Motif. The basis of the GUI usedfor the Motorola OMC-R MMI.

OSS Operator Services System.

Overlap Overlap sending means that digits are sent from one systemto another as soon as they are received by the sendingsystem. A system using ~ will not wait until it has received alldigits of a call before it starts to send the digits to the nextsystem. This is the opposite of en bloc sending where alldigits for a given call are sent at one time.

P



G–35

P

PA Power Amplifier.

PAB Power Alarm Board.

PABX Private Automatic Branch eXchange.

PAD Packet Assembler/Disassembler facility.

Paging The procedure by which a GSM PLMN fixed infrastructureattempts to reach an MS within its location area, before anyother network-initiated procedure can take place.

PATH CEPT 2 Mbit/s route through the BSS network.

PBUS Processor Bus.

PBX Private Branch eXchange.

PC Personal Computer.

PCH Paging CHannel. A GSM common control channel used tosend paging messages to the MSs.

PCHN Paging Channel Network.

PCHN Physical Channel.

PCM Pulse Code Modulation (see also 2 Mbit/s link which is thephysical bearer of PCM).

PCN Personal Communications Network.

PCR Preventative Cyclic Retransmission. A form of errorcorrection suitable for use on links with long transmissiondelays, such as satellite links.

PCU Packet Control Unit (p/o GPRS).

PCU Picocell Control unit (p/o M-Cellaccess).

pd Potential difference.

PD Protocol Discriminator.

PD Public Data.

PDB Power Distribution Board.

PDF Power Distribution Frame (MSC/LR).

PDN Public Data Networks.

PDU Power Distribution Unit.

PDU Protected Data Unit.

PEDC Pan European Digital Cellular.

Peg A single incremental action modifying the value of a statistic.

Pegging Modifying a statistical value.

PH Packet Handler.

PH PHysical (layer).

PHI Packet Handler Interface.

PI Presentation Indicator.

Picocell A cell site where the base station antenna is mounted within abuilding.

PICS Protocol Implementation Conformance Statement.

P



G–36

PID Process IDentifier/Process ID.

PIM PCM Interface Module (MSC).

PIN Personal Identification Number.

PIN Problem Identification Number.

PIX Parallel Interface Extender half size board. Customer alarminterface (p/o BSS).

PIXT Protocol Implementation eXtra information for Testing.

PK Primary Key. A database column attribute, the primary key isa not-null, non-duplicate index.

Plaintext Unciphered data.

PlaNET Frequency planning tool.

PLL Phase Lock Loop (refers to phase locking the GCLK in theBTS).

PLMN Public Land Mobile Network. The mobile communicationsnetwork.

PM Performance Management. An OMC application.

PM-UI Performance Management User Interface.

PMA Prompt Maintenance Alarm. An alarm report level; immediateaction is necessary (see also DMA).

PMS Pseudo MMS.

PMUX PCM MUltipleXer.

PN Permanent Nucleus (of GSM).

PNE Présentation des Normes Européennes.

POI Point of Interconnection (with PSTN).

POTS Plain Old Telephone Service (basic telephone services).

p/o Part of.

pp, p-p Peak-to-peak.

PP Point-to-Point.

ppb Parts per billion.

PPE Primative Procedure Entity.

ppm Parts per million (x 10–6).

Pref CUG Preferential CUG.

Primary Cell A cell which is already optimized in the network and has aco-located neighbour whose cell boundary follows theboundary of the said cell. The primary cell has a preferredband equal to the frequency type of the coincident cell.

PROM Programmable Read Only Memory.

Ps Location probability.

PSA Periodic Supervision of Accessability.

PSAP Presentation Services Access Point.

PSM Power Supply Module.

P



G–37

PSPDN Packet Switched Public Data Network. Public datacommunications network. x.25 links required for NE to OMCcommunications will probably be carried by PSPDN.

PSTN Public Switched Telephone Network. The UK land linetelephone network.

PSU Power Supply Unit.

PSW Pure Sine Wave.

PTO Public Telecommunications Operator.

PUCT Price per Unit Currency Table.

PVC Permanent Virtual Circuit.

PW Pass Word.

PWR Power.

PXPDN Private eXchange Public Data Network.

Q



G–38

QQA Q (Interface) – Adapter.

Q3 Interface between NMC and GSM network.

Q-adapter Used to connect MEs and SEs to TMN (GSM Rec. 12.00).

QAF Q-Adapter Function.

QEI Quad European Interface. Interfaces four 2 Mbit/s circuits toTDM switch highway (see MSI).

QIC Quarter Inch Cartridge (Data storage format).

QOS Quality Of Service.

Quiescent mode IDS intermediate state before shutdown.

R



G–39

RR Value of reduction of the MS transmitted RF power relative to

the maximum allowed output power of the highest powerclass of MS (A).

RA RAndom mode request information field.

RAB Random Access Burst.

RACCH Random Access Control CHannel. A GSM common controlchannel used to originate a call or respond to a page.

RACH Random Access CHannel.

RAM Random Access Memory.

RAND RANDom number (used for authentication).

RATI Receive Antenna Transceiver Interface.

RAx Rate Adaptation.

RBDS Remote BSS Diagnostic System (a discontinued Motoroladiagnostic facility).

RBER Residual Bit Error Ratio.

RBTS Remote Base Transceiver Station.

RCB Radio Control Board (p/o DRCU).

RCI Radio Channel Identifier.

RCP Radio Control Processor.

RCU Radio Channel Unit. Contains transceiver, digital controlcircuits, and power supply (p/o BSS) (see DRCU).

RCVR Receiver.

RDBMS Relational DataBase Management System (INFORMIX).

RDI Radio Digital Interface System.

RDIS Restricted Digital Information.

RDM Reference Distribution Module.

RDN Relative Distinguished Name. A series of RDN form a uniqueidentifier, the distinguished name, for a particular networkelement.

REC, Rec RECommendation.

REJ REJect(ion).

REL RELease.

RELP Residual Excited Linear Predictive.

RELP-LTP RELP Long Term Prediction. A name for GSM full rate (seefull rate).

resync Resynchronize/resynchronization.

REQ REQuest.

Revgen A Motorola DataGen utility for producing an MMI script from abinary object database.

RF Radio Frequency.

R



G–40

RFC, RFCH Radio Frequency Channel. A partition of the system RFspectrum allocation with a defined bandwidth and centrefrequency.

RFE Receiver Front End (shelf).

RFEB Receiver Front End Board (p/o DRCU II).

RFI Radio Frequency Interference.

RFM Radio Frequency Module.

RFN Reduced TDMA Frame Number.

RFU Reserved for Future Use.

RJ45 Network cable/Connector type.

RISC Reduced Instruction Set Computer.

RL Remote login.

RLC Release Complete.

RLP Radio Link Protocol. An ARQ protocol used to transfer userdata between an MT and IWF. See GSM 04.22.

RLR Receiver Loudness Rating.

RLSD ReLeaSeD.

RMS Root Mean Square (value).

RMSU Remote Mobile Switching Unit.

RNTABLE Table of 128 integers in the hopping sequence.

ROM Read Only Memory.

ROSE Remote Operations Service Element. An ASE which carriesa message between devices over an association establishedby ASCE (a CCITT specification for O & M) (OMC).

Roundtrip Time period between transmit and receive instant of atimeslot in the BTS, propagation determined by the responsebehaviour of the MS and the MS to BTS delay distance.

RPE Regular Pulse Excited.

RPE-LTP Regular Pulse Excitation - Long Term Prediction. The GSMdigital speech coding scheme.

RPOA Recognised Private Operating Agency.

RPR Read Privilege Required. Access to the column is allowedonly for privileged accounts.

RR Radio Resource management.

RR Receive Ready (frame).

RRSM Radio Resource State Machine.

RS232 Standard serial interface.

RSE Radio System Entity.

RSL Radio Signalling Link.

RSLF Radio System Link Function.

RSLP Radio System Link Processor.

RSS Radio SubSystem (replaced by BSS).

RSSI Received Signal Strength Indicator.

R



G–41

RSZI Regional Subscription Zone Identity.

RTC Remotely Tuneable Channel Combiner.

RTE Remote Terminal Emulator.

RTF Radio Transceiver Function.

RTF Receive Transmit Functions.

RTS Request to Send. Method of flow control (RS232 Interface).

RU Rack Unit.

Run level System processor operating mode.

Rx Receive(r).

RXCDR Remote Transcoder.

RXF Receive Function (of the RTF).

RXLEV-D Received signal level downlink.

RXLEV-U Received signal level uplink.

RXQUAL-D Received signal quality downlink.

RXQUAL-U Received signal quality uplink.

RXU Remote Transcoder Unit. The shelf which houses theremote transcoder modules in a BSSC cabinet at a remotetranscoder site.

S



G–42

SS/W SoftWare.

SABM Set Asynchronous Balanced Mode. A message whichestablishes the signalling link over the air interface.

SABME SABM Extended.

SACCH Slow Associated Control CHannel. A GSM control channelused by the MS for reporting RSSI and signal qualitymeasurements.

SACCH/C4 Slow Associated Control CHannel/SDCCH/4.

SACCH/C8 Slow Associated Control CHannel/SDCCH/8.

SACCH/T Slow Associated Control CHannel/Traffic channel.

SACCH/TF Slow Associated Control CHannel/Traffic channel Full rate.

SACCH/TH Slow Associated Control CHannel/Traffic channel Half rate.

SAGE A brand of trunk test equipment.

SAP Service Access Point. In the reference model for OSI, SAPsof a layer are defined as gates through which services areoffered to an adjacent higher layer.

SAP System Audits Process.

SAPI Service Access Point Indicator (identifier).

SAW Surface Acoustic Wave.

SB Synchronization Burst (see Synchronization burst).

SBUS Serial Bus.

SC Service Centre (used for Short Message Service).

SC Service Code.

SCCA System Change Control Administration. Software modulewhich allows full or partial software download to the NE(OMC).

SCCP Signalling Connection Control Part (6-8).

SCEG Speech Coding Experts Group (of GSM).

SCH Synchronization CHannel. A GSM broadcast control channelused to carry information for frame synchronization of MSsand identification of base stations.

SCI Status Control Interface.

SCIP Serial Communication Interface Processor.

SCM Status Control Manager.

SCN Sub-Channel Number. One of the parameters defining aparticular physical channel in a BS.

SCP Service Control Point (an intelligent network entity).

SCSI Small Computer Systems Interface.

SCU Slim Channel Unit.

SCU900 Slim Channel Unit for GSM900.

SDCCH Stand-alone Dedicated Control CHannel. A GSM controlchannel where the majority of call setup occurs. Used forMS to BTS communications before MS assigned to TCH.

S



G–43

SDL Specification Description Language.

SDT SDL Developement Tool.

SDU Service Data Unit.

SDR Special Drawing Rights (an international “basket” currency forbilling).

SE Support Entity (GSM Rec. 12.00).

Secondary Cell A cell which is not optimized in the network and has aco-located neighbour whose cell boundary follows theboundary of the said cell. The secondary cell has a preferredband the same as that of its own frequency type.

SEF Support Entity Function (GSM Rec.12.00).

SFH Slow Frequency Hopping.

SI Screening Indicator.

SI Service Interworking.

SI Supplementary Information.

SIA Supplementary Information A.

SID Silence Descriptor.

SIF Signal Information Field. The bits of a message signal unitthat carry information for a certain user transaction; the SIFalways contains a label.

SIM Subscriber Identity Module. Removable module which isinserted into a mobile equipment; it is considered as part ofthe MS. It contains security related information (IMSI, Ki,PIN), other subscriber related information and the algorithmsA3 and A8.

SIMM Single Inline Memory module.

SIMM System Integrated Memory Module.

SIO Service Information Octet. Eight bits contained in a messagesignal unit, comprising the service indicator and sub-servicefield.

SITE BSC, BTS or collocated BSC-BTS site.

SIX Serial Interface eXtender. Converts interface levels to TTLlevels. Used to extend 2 serial ports from GPROC to externaldevices (RS232, RS422, and fibre optics).

SK Secondary Key. A database column attribute, the secondarykey indicates an additional index and/or usage as acomposite key.

SL Signalling Link.

SLNK Serial Link.

SLR Send Loudness Rating.

SLTM Signalling Link Test Message.

SM Switch Manager.

SM Summing Manager.

SMAE System Management Application Entity (CCITT Q795, ISO9596).

SMCB Short Message Cell Broadcast.

S



G–44

SME Short Message Entity.

SMG Special Mobile Group.

SMP Motorola Software Maintenance Program.

SMS Short Message Service.

SMSCB Short Message Service Cell Broadcast.

SMS-SC Short Message Service - Service Centre.

SMS/PP Short Message Service/Point-to-Point.

Smt Short message terminal.

SN Subscriber Number.

SND SeND.

SNDR SeNDeR.

SNR Serial NumbeR.

SOA Suppress Outgoing Access (CUG SS).

SP Service Provider. The organisation through which thesubscriber obtains GSM telecommunications services. Thismay be a network operator or possibly a separate body.

SP Signalling Point.

SP Special Product.

SP SPare.

SPC Signalling Point Code.

SPC Suppress Preferential CUG.

SPI Signalling Point Inaccessible.

SPP Single Path Preselector.

SQE Signal Quality Error.

SQL Structured Query Language.

SRD Service Request Distributor.

SRES Signed RESponse (authentication).

SS Supplementary Service. A modification of, or a supplementto, a basic telecommunication service.

SS System Simulator.

SSA SCCP messages, Subsystem-allowed (see CCITT Q.712para 1.15).

SSAP Site System Audits Processor.

SSC Supplementary Service Control string.

SSF Subservice Field. The level 3 field containing the networkindicator and two spare bits.

SSM Signalling State Machine.

SSN SubSystem Number.

SSP Service Switching Point (an intelligent network element).

SSP SCCP messages, Subsystem-prohibited (see CCITT Q.712para 1.18).

SSP SubSystem Prohibited message.

S



G–45

SSS Switching SubSystem (comprising the MSC and the LRs).

SS7 ANSI Signalling System No. 7 (alias C7).

STAN Statistical ANalysis (processor).

STAT STATistics.

stats Statistics.

STC System Timing Controller.

STMR Side Tone Masking rating.

SUERM Signal Unit Error Rate Monitor.

STP Signalling Transfer Point.

Superframe 51 traffic/associated control multiframes or 26broadcast/common control multiframes (period 6.12s).

Super user User account that can access all files, regardless ofprotection settings, and control all user accounts.

SURF Sectorized Universal Receiver Front-end (Used inHorizonmacro).

SVC Switch Virtual Circuit.

SVM SerVice Manager.

SVN Software Version Number.

SW Software.

SWFM SoftWare Fault Management.

sync synchronize/synchronization.

Synchronization burst Period of RF carrier less than one timeslot whose modulationbit stream carries information for the MS to synchronize itsframe to that of the received signal.

SYS SYStem.

SYSGEN SYStem GENeration. The Motorola procedure for loading aconfiguration database into a BTS.

T



G–46

TT Timer.

T Transparent.

T Type only.

T43 Type 43 Interconnect Board. Provides interface to 12unbalanced (6-pair) 75 ohm (T43 coax connectors) lines for2 Mbit/s circuits (See BIB).

TA Terminal Adaptor. A physical entity in the MS providingterminal adaptation functions (see GSM 04.02).

TA Timing Advance.

TAC Type Approval Code.

TACS Total Access Communications System (European analoguecellular system).

TAF Terminal Adaptation Function.

TATI Transmit Antenna Transceiver Interface. The TATI consistsof RF combining equipments, either Hybrid or CavityCombining. (See CCB).

TAXI Transparent Asynchronous Transmitter/Receiver Interface(physical layer).

TBD To Be Determined.

TBR Technical Basis for Regulation.

TBUS TDM Bus.

TC Transaction Capabilities.

TCAP Transaction Capabilities Application Part (of SignallingSystem No. 7).

TCB TATI Control Board.

TCH Traffic CHannel. GSM logical channels which carry eitherencoded speech or user data.

TCH/F A full rate TCH.

TCH/F2.4 A full rate TCH at � 2.4 kbit/s.

TCH/F4.8 A full rate TCH at 4.8 kbit/s.

TCH/F9.6 A full rate TCH at 9.6 kbit/s.

TCH/FS A full rate Speech TCH.

TCH/H A half rate TCH.

TCH/H2.4 A half rate TCH at � 2.4 kbit/s.

TCH/H4.8 A half rate TCH at 4.8 kbit/s.

TCH/HS A half rate Speech TCH).

TCI Transceiver Control Interface.

TCP/IP Transmission Control Protocol/Internet Protocol.

TC-TR Technical Commitee Technical Report.

TCU Transceiver Control Unit.

TDF Twin Duplexed Filter. (Used in M-Cellhorizon).

TDM Time Division Multiplexing.

T



G–47

TDMA Time Division Multiple Access.

TDU TopCell Digital Unit.

TE Terminal Equipment. Equipment that provides the functionsnecessary for the operation of the access protocols by theuser.

Tei Terminal endpoint identifier.

TEI Terminal Equipment Identity.

TEMP TEMPorary.

TEST TEST control processor.

TFA TransFer Allowed.

TFP TransFer Prohibited.

TFTP Trivial File Transfer Protocol.

TI Transaction Identifier.

Timeslot The multiplex subdivision in which voice and signalling bitsare sent over the air. Each RF carrier is divided into 8timeslots.

Timing advance A signal sent by the BTS to the MS. It enables the MS toadvance the timing of its transmission to the BTS so as tocompensate for propagation delay.

TLV Type, Length and Value.

TM Traffic Manager.

TMI TDM Modem Interface board. Provides analogue interfacefrom IWF to modems for 16 circuits (p/o IWF).

TMM Traffic Metering and Measuring.

TMN Telecommunications Management Network. Theimplementation of the Network Management functionalityrequired for the PLMN is in terms of physical entities whichtogether constitute the TMN.

TMSI Temporary Mobile Subscriber Identity. A unique identitytemporarily allocated by the MSC to a visiting mobilesubscriber to process a call. May be changed between callsand even during a call, to preserve subscriber confidentiality.

TN Timeslot Number.

TON Type Of Number.

Traffic channels Channels which carry user’s speech or data (see also TCH).

Traffic unit Equivalent to an erlang.

Training sequence Sequence of modulating bits employed to facilitate timingrecovery and channel equalization in the receiver.

TRAU Transcoder Rate Adaption Unit.

TRU TopCell Radio unit.

TRX Transceiver(s). A network component which can serve fullduplex communication on 8 full-rate traffic channels accordingto specification GSM 05.02. If Slow Frequency Hopping(SFH) is not used, then the TRX serves the communicationon one RF carrier.

TS Technical Specification.

T



G–48

TS TeleService.

TS TimeSlot (see Timeslot).

TSA TimeSlot Acquisition.

TSA TimeSlot Assignment.

TSDA Transceiver Speech & Data Interface.

TSC Training Sequence Code.

TSI TimeSlot Interchange.

TSDI Transceiver Speech and Data Interface.

TSM Transceiver Station Manager.

TSW Timeslot SWitch.

TTCN Tree and Tabular Combined Notation.

TTL Transistor to Transistor Logic.

TTY TeleTYpe (refers to any terminal).

TU Traffic Unit.

TUP Telephone User Part (SS7).

TV Type and Value.

Tx Transmit(ter).

TXF Transmit Function (of the RTF).

TXPWR Transmit PoWeR. Tx power level in theMS_TXPWR_REQUEST and MS_TXPWR_CONFparameters.

TxBPF Transmit Bandpass Filter.

U



G–49

UUA Unnumbered Acknowledgment. A message sent from the

MS to the BSS to acknowledge release of radio resourceswhen a call is being cleared.

UDI Unrestricted Digital Information.

UDP User Datagram Protocol.

UDUB User Determined User Busy.

UHF Ultra High Frequency.

UI Unnumbered Information (Frame).

UIC Union International des Chemins de Fer.

UID User ID. Unique number used by the system to identify theuser.

UL Upload (of software or database from an NE to a BSS).

Um Air interface.

UMTS Universal Mobile Telecommunication System.

UPCMI Uniform PCM Interface (13 bit).

UPD Up to Date.

Uplink Physical link from the MS towards the BTS (MS transmits,BTS receives).

UPS Uninterruptable Power Supply.

UPU User Part Unavailable.

Useful part of burst That part of the burst used by the demodulator; differs fromthe full burst because of the bit shift of the I and Q parts ofthe GMSK signal.

USSD Unstructured Supplementary Service Data.

UUS User-to-User Signalling supplementary service.

V



G–50

VV Value only.

VA Viterbi Algorithm (used in channel equalizers).

VAD Voice Activity Detection. A process used to identify presenceor absence of speech data bits. VAD is used with DTX.

VAP Videotex Access Point.

VBS Voice Broadcast Service.

VC Virtual Circuit.

VCO Voltage Controlled Oscillator.

VCXO Voltage Controlled Crystal Oscillator.

VDU Visual Display Unit.

VGCS Voice Group Call Service.

VLR Visitor Location Register. A GSM network element whichprovides a temporary register for subscriber information for avisiting subscriber. Often a part of the MSC.

VLSI Very Large Scale Integration (in ICs).

VMSC Visited MSC. (Recommendation not to be used).

VOX Voice Operated Transmission.

VPLMN Visited PLMN.

VSC Videotex Service Centre.

V(SD) Send state variable.

VSP Vehicular Speaker Phone.

VSWR Voltage Standing Wave Ratio.

VTX host The components dedecated to Videotex service.

W



G–51

WWAN Wide Area Network.

WPA Wrong Password Attempts (counter).

WS Work Station. The remote device via which O&M personnelexecute input and output transactions for networkmanagement purposes.

WSF Work Station Function block.

WWW World Wide Web.

X



G–52

XX.25 CCITT specification and protocols for public packet-switched

networks (see PSPDN).

X.25 link A communications link which conforms to X.25 specificationsand uses X.25 protocol (NE to OMC links).

XBL Transcoder to BSS Link. The carrier communications linkbetween the Transcoder (XCDR) and the BSS.

XCB Transceiver Control Board (p/o Transceiver).

XCDR Full-rate Transcoder. Provides speech transcoding and 4:1submultiplexing (p/o BSS, BSC or XCDR).

XCDR board The circuit board required to perform speech transcoding atthe BSS or (R)XCDR). Also known as the MSI (XCDR)board. Interchangeable with the GDP board.

XFER Transfer.

XID eXchange IDentifier.

X-Term X terminal window.

Z



G–53

ZZC Zone Code

Z



G–54

capacity enhancing techniques and multi layer systems

Documents