flexi multiradio 10 bts edge feature descriptions

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GSM/EDGE BSS, Rel.RG30(BSS), OperatingDocumentation, Issue 08,Change Delivery 01

Flexi Multiradio 10 Base

Station EDGE FeatureDescriptions

DN09167685

Issue 01F

Approval Date 2015-08-21

Nokia Networks



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Flexi Multiradio 10 Base Station EDGE Feature Descriptions

2 DN09167685 Issue: 01F



Table of Contents

This document has 142 pages

Summary of changes................................................................... 10

1 Overview of features in Flexi Multiradio BTS software release GF1......................................................................................................11

2 Data/Voice....................................................................................12

2.1 BSS20088 Dual Transfer Mode................................................... 12

2.2 BSS9006 General Packet Radio Ser vice (GPRS)....................... 12

2.3 BSS10083 Enhanced General Packet Radio Service (MCS-1 -MSC-9)......................................................................................... 13

2.4 BSS7003 High Speed Circuit Switched Data and BSS7037 14.4kbit/s Data Services..................................................................... 16

2.5 BSS10004 Adaptive Multi Rate Codec (AMR)............................. 17

2.6 BSS7005 Intelligent Frequency Hopping and BSS6114 IntelligentUnderlay-Overlay......................................................................... 18

2.7 BSS20960 Wideband AMR and BSS21118 TFO for AMR...........19

2.8 Long Reach TCH TSL..................................................................19

2.9 BSS101482 Extended Cell functionalities for Flexi Multiradio BTS.19

2.10 BSS21388 Random Fill Bits.........................................................22

2.11 BSS21309 OSC Half Rate with S AIC MS.................................... 22

2.12 BSS21534 OSC Full Rate with SAIC MS.....................................24

2.13 BSS21325 8k TRAU for OSC AMR FR .......................................24

2.14 BSS21313 OSC support for VAMOS handsets............................25

2.15 BSS21537 AQPSK with VAMOS 2 Handsets.............................. 26

2.16 RG301666 EGPRS Downlink Power Control...............................28

2.17 BSS21542 OSC Capability Test for Handsets............................. 29

2.18 RG602124 Composite Multi Site Transmission............................30

2.19 RG602125 High Speed Rail Handover........................................ 32

2.19.1 CMST configuration restrictions(BSC):........................................ 33

3 Interworking..................................................................................36

3.1 BSS10101 GSM-WCDMA Interworking....................................... 363.2 BSS11086 Support for Enhanced Measurement Report............. 36

3.3 BSS21520: RF Sharing GSM - LTE............................................. 37

3.4 Collecting logs using Snapshot feature........................................38

4 Operability.................................................................................... 40

4.1 2G Flexi BTS Manager Compatibility Launcher........................... 40

4.2 BTS Trace Tool.............................................................................42

4.3 Antenna VSWR measurement..................................................... 42

4.3.1 Antenna boosting on TCH-only TRX antenna lines..................... 44

4.4 BSC download of Abis mapping...................................................44


Issue: 01F DN09167685 3



4.5 BSS20847 Automatic commissioning of the Flexi Multiradio BTSGSM/EDGE..................................................................................45

4.6 BSS20817 End to End Downlink Abis Performance Monitor ...... 46

4.7 BSS20063 Space Time Interference Rejection Combining..........464.8 BSS20040 User Access Level Control (UALC)............................47

4.9 BSS11047 Intelligent shutdown for Flexi Multiradio BTSGSM/EDGE..................................................................................49

4.10 Remote mode of 2G Flexi BTS Site Manager .............................50

4.11 BSS10063 Rx Antenna Supervision by Comparing RSSI............51

4.12 BSS9068 BTS SW management................................................. 53

4.13 BSS9058 BTS fault recovery....................................................... 54

4.14 BSS9063 Abis loop test............................................................... 54

4.15 BSS9062 BTS supervision...........................................................54

4.16 BSS9061 Temperature control system.........................................55

4.17 BSS9060 TRX Test...................................................................... 554.18 TRX Loop Test............................................................................. 57

4.19 BSS9059 Nokia BTS resets.........................................................57

4.20 BTS Auto-detection......................................................................58

4.20.1 BSS9056 Auto-detection of Site Configuration............................ 58

4.21 48 V DC input voltage supervision...............................................58

4.22 BSS20958 Energy saving mode for BCCH TRX..........................59

4.23 Resource Allocation Algorithm.....................................................59

4.23.1 Overview...................................................................................... 59

4.23.2 General resource allocation rules................................................ 59

4.23.3 RF allocation procedure............................................................... 604.23.4 Alarms due to resource allocation................................................65

4.23.5 Smart BCCH recovery..................................................................65

4.24 BSS21362 Fast BSS Restart....................................................... 67

4.25 BSS21316 Flexi BTS Autoconnection..........................................68

4.26 BSS101574: Air Path Loss Measurement ...................................68

4.27 BSS101583 Precise Rx Level Management................................ 69

4.28 BSS101584 Precise Timing Advance Management.................... 69

4.29 BSS101585 Precise Power Level Management.......................... 69

4.30 BSS101586 Adjacent Cell Rx Level Management.......................70

4.31 Power Cable Auto-detection........................................................ 70

4.32 Antenna Hopping......................................................................... 71

4.33 BSS101696 Small form-factor pluggable (SFP) Transceiver Diagnostics...................................................................................72

4.34 BSS20984: 2G TRX Automatic Power Down...............................72

4.35 RG301936: Intelligent MCPA TRX Shutdown.............................. 74

4.36 BSS101688 BSS support for FSM3............................................. 78

4.37 BSS10104 Intelligent Downlink Diversity..................................... 78

4.38 RG301980 CMST Support with FSM3 ........................................78

5 Site solutions................................................................................79

5.1 BSS10046 Multi BCF Control.......................................................79

5.2 BSS9055 Clock Synchronisation between Base Stations............79


4 DN09167685 Issue: 01F



5.3 1 Pulse Per Second (PPS)...........................................................81

5.4 BSS10069 Synchronized BSS.....................................................81

5.4.1 BSS20371 BSS Site Synchronisation Recovery Improvement....82

5.4.2 BSS11073 Recovery for BSS and Site Synchronisation..............825.5 Operating bands...........................................................................83

5.6 BTS2043 BTS External Alarms and Controls (EAC)....................85

5.7 BTS2020 RX antenna diversity....................................................85

5.8 BTS configurations.......................................................................86

5.8.1 Dedicated mode...........................................................................86

5.8.2 Concurrent mode......................................................................... 86

5.8.3 Shared RX diversity..................................................................... 87

5.8.4 Antenna-optimized configurations................................................87

5.8.5 Feederless configurations............................................................ 88

5.8.6 Maximum configuration supported............................................... 89

5.9 Remote Electrical Tilt (RET).........................................................90

5.10 MHA types supported...................................................................91

5.11 RG301397 Co-siting with BS2xx..................................................91

5.12 RF Module/RRH chaining............................................................ 92

5.12.1 GSM - RF Module chaining.......................................................... 92

5.12.2 GSM - RRH chaining....................................................................93

5.12.3 Common BCCH chaining............................................................. 94

5.12.4 RF Module - RRH chaining.......................................................... 96

5.12.5 Examples of chained configurations............................................ 97

5.13 BSS21507 Flexible MCPA TX Power Pooling..............................99

5.14 RG301743: Adjustable UL RLT Increase Step...........................1035.15 BSS101623 Energy Efficient Coverage..................................... 104

5.16 RG301726 Uplink Min RX level Based Access .........................104

5.17 RG301965 GPS 1PPS+TOD Sync Support...............................105

6 Basic GSM operation................................................................. 106

6.1 Static Power levels.....................................................................106

6.2 BSS21113 Increased dynamic SDCCH capacity....................... 106

6.3 BSS20872 Robust AMR signaling............................................. 106

6.4 BSS20588 TRAU bicasting in AMR FR/HR handover............... 108

6.5 Basic GSM features................................................................... 108

6.6 BSS6071 Enhanced Full Rate Codec........................................ 109

6.7 BTS2023 Downlink and uplink DTX...........................................109

6.8 BTS2503 Compressed Abis timeslot allocation..........................110

6.9 BTS2067 Fast Associated Control Channel (FACCH) Call Setup...110

6.10 BSS7036 Dynamic SDCCH Allocation.......................................110

6.11 BTS2024 Synthesized frequency hopping..................................111

6.12 BTS2013 Baseband Frequency Hopping................................... 111

6.13 BTS2037 Air interface measurement pre-processing.................112

6.14 BTS2012 BTS time base reference from PCM...........................112

6.15 BTS2133 Short Message Service (SMS) point-to-point............. 112


Issue: 01F DN09167685 5



6.16 BTS2033 Short message cell broadcast.................................... 112

6.17 BSS6025 Short Message Service Cell Broadcast withDiscontinuous Receiving (SMS-CB DRX).................................. 112

6.18 BSS6083 Mobile Station (MS) speed detection......................... 1136.19 BSS20093 A5/3 ciphering.......................................................... 114

6.20 Multiple Operator BSS Configuration (MOBBS).........................115

6.21 BSS101411 Extended BCCH..................................................... 117

6.22 BSS21538 Extended Common Contr ol Channel (CCCH)..........117

6.23 BSS21445 Packet Abis Congestion r eaction............................. 117

6.24 BTS Overload Control................................................................ 118

6.25 RG301917 Triple RFM 3*80W in 1900 band..............................120

6.26 RG301703 FXEB support in BSS.............................................. 120

6.27 RG301704 5W Output Power Step size for Flexi Multiradio...... 120

6.28 RG301756 FXDB support in BSS.............................................. 120

6.29 RG301844 BSS Support for High Power RRH.......................... 121

6.30 RG302087 Narrow LTE RF Bandwidth...................................... 121

7 Transmission..............................................................................122

7.1 Basic transmission.....................................................................122

7.1.1 Abis Trunk Transmission for E1 (ETSI) interface....................... 122

7.1.2 Abis Trunk Transmission Allocation for T1 (ANSI) Interface...... 122

7.1.3 Abis Trunk Signaling.................................................................. 123

7.1.4 Network Synchronisation........................................................... 123

7.1.5 BSS9065 Transmission Operability............................................124

7.1.6 BSS21234 Support for BTS PWE Counters at BSC/NetAct...... 124

7.2 Transmission solutions...............................................................125

7.2.1 PDH traffic routing......................................................................125

7.2.2 BSS30280 Abis loop protection................................................. 126

7.2.3 Redundant Abis Trunk................................................................127

7.3 BSS10045 Dynamic Abis allocation...........................................128

7.4 BSS5850 Satellite Abis.............................................................. 129

7.5 BSS21497 Enhanced satellite support.......................................129

7.6 BSS21439 Packet Abis Sync. ToP IEEE1588v2........................129

7.7 BSS21454 Packet Abis over Ethernet....................................... 130

7.8 BSS21438 Packet Abis over Satellite........................................ 130

7.9 BSS30450 Packet Abis Synchronous Ethernet......................... 1317.10 BSS21440 Packet Abis over TDM............................................. 131

7.11 BSS21271 Abis Delay Measurement (TDM, PWE3)................. 133

7.12 BSS30395 Packet Abis Delay Measurement.............................134

7.13 BSS21503 FlexiPacket Radio Connectivity............................... 134

7.14 BSS101417 QoS Aware Ethernet Switching..............................135

7.15 BSS101459 Full GE Support in FIYB/FIQB............................... 136

7.16 BSS101414 Packet Abis Transport Media Conversion..............137

7.17 Functional description................................................................ 138

7.18 RG301994 Longer Sync Cable between FSMx & ESMx........... 140

8 Appendix A.................................................................................142


6 DN09167685 Issue: 01F



List of FiguresFigure 1 Incremental Redundancy scheme...................................................... 15

Figure 2 Typical data throughputs for 14.4 kbit/s (non-transparent) and 9.6kbit/s coding (this depends on the NW radio conditions)....................17

Figure 3 AQPSK constellation.......................................................................... 27

Figure 4 OSC Capability Test for Handsets...................................................... 29

Figure 5 Composite cell concept in multi-floor solution.................................... 31

Figure 6 CMST in railway environment.............................................................32

Figure 7 Collecting logs using Snapshot feature.............................................. 39

Figure 8 Compatibility launcher-local connection............................................. 40

Figure 9 Compatibility launcher-connecting......................................................41

Figure 10 Compatibility launcher-Create File option...........................................41

Figure 11 Uninstall versions of 2G Flexi BTS Site Manager...............................42

Figure 12 Setting VSWR limits using 2G Flexi BTS Site Manager.....................43

Figure 13 2G Flexi BTS Site Manager connected in remote mode.................... 51

Figure 14 TRX Test window................................................................................56

Figure 15 RF resource allocation........................................................................62

Figure 16 Power budget..................................................................................... 63

Figure 17 ARFCN effects....................................................................................64

Figure 18 Frequency budget...............................................................................65

Figure 19 Smart BCCH recovery when interchangeability is not possible..........66

Figure 20 Smart BCCH recovery when interchangeability is possible................67

Figure 21 TRX power down based on the MCPA priority................................... 76

Figure 22 Multi BCF configuration...................................................................... 79

Figure 23 Synchronized BSS example in Flexi Compact BTS chain..................83

Figure 24 Common BCCH configuration............................................................ 85

Figure 25 Flexi Multiradio BTS in dedicated mode.............................................86

Figure 26 Flexi Multiradio BTS in concurrent mode............................................87

Figure 27 Basic configuration with RX diversity sharing.....................................87

Figure 28 Feederless rooftop site.......................................................................89

Figure 29 108 TRX configuration........................................................................90

Figure 30 Single chain of three RF Modules...................................................... 97

Figure 31 Three chains of two RF Modules........................................................97

Figure 32 Three chains of two RRH................................................................... 98

Figure 33 Six RRH distance between System Module and RRH upto 10 km andRRH to RRH 3.0 km (two chains).......................................................98

Figure 34 Three chains of two RF Modules in common BCCH..........................98

Figure 35 Three RRHs in once chain and three RF Modules in one chain........ 99

Figure 36 Coverage without and with flexible MCPA..........................................99

Figure 37 Power allocation without Flexible MCPA TX Power Pooling............ 100


Issue: 01F DN09167685 7



Figure 38 Power allocation with Flexible MCPA TX Power Pooling................. 101

Figure 39 SDB deployed in one sector.............................................................104

Figure 40 TRAU bicasting in AMR FR/HR handover........................................108

Figure 41 Dynamic SDCCH allocation.............................................................. 111

Figure 42 SMS-CB DRX Schedule Period........................................................113

Figure 43 MS speed detection used for handover decision..............................114

Figure 44 Loop principle................................................................................... 126

Figure 45 Packet Abis over Ethernet................................................................ 130

Figure 46 Round trip time/Abis delay measurement.........................................133

Figure 47 QoS Aware Ethernet Switching........................................................ 135

Figure 48 Ethernet-based BTS daisy allocation with BTS integrated Ethernetswitch................................................................................................136

Figure 49 Optical and electrical GE connections..............................................137Figure 50 Optical and electrical GE connections with MWRs...........................137

Figure 51 Packet Abis Transport Media Conversion........................................ 137

Figure 52 Without Composite Multi Site Transmission feature.........................138

Figure 53 With Composite Multi Site Transmission f eature..............................139


8 DN09167685 Issue: 01F



List of TablesTable 1 Peak data rates for single slot EGPRS ..............................................13

Table 2 Corresponding maximum data rates with different channel coding....16Table 3 Channel and speech codec modes for AMR...................................... 18

Table 4 Logical TRX ID, number of TRXs, and total number of CMST cellnodes.................................................................................................. 33

Table 5 Number of Logical TRXs and depth of single optical chain (number of RRH per optical chain)....................................................................... 34

Table 6 Software requirements....................................................................... 37

Table 7 Hardware requirements......................................................................37

Table 8 Software requirements for different network elements....................... 76

Table 9 Hardware requirements for different network elements......................77

Table 10 Flexi Multiradio RF Module variants................................................... 84

Table 11 Flexi Multiradio RRH Module variants................................................ 84

Table 12 Antenna-optimized configurations...................................................... 88

Table 13 BTS combinations and sync cables....................................................89

Table 14 GSM RF Module chaining configuration.............................................92

Table 15 GSM RRH chaining configuration.......................................................93

Table 16 Common BCCH chaining configuration..............................................94

Table 17 RF Module and RRH chaining configuration...................................... 96

Table 18 TRX power classes limit for MCPA power budget 60 W...................101

Table 19 TRX power classes limit for MCPA power budget 60 W and GSM 52W...................................................................................................... 102

Table 20 TRX power classes limit for MCPA power budget 60 W and GSM 40W..........................................................................................................102

Table 21 Configurations supporting RFM........................................................102

Table 22 Configurations supporting RRH........................................................103

Table 23 2 sectors using same pipes configurations.......................................115

Table 24 Software requirements..................................................................... 125

Table 25 Software requirements..................................................................... 127

Table 26 Number of 16 kbps DAP sub channels used with each CS and MCS....

128


Issue: 01F DN09167685 9



Summary of changes

Changes between document issues are cumulative. Therefore, the latest document

issue contains all changes made to previous issues.

Changes between issues 01E (2015-07- 16) and 01F (2015-08-21)

Software requirements table has been added in the following chapters:

• PDH traffic routing

• BSS30280 Abis loop protection

Redundant Abis Trunk chapter has been updated with a note.

Changes between issues 01D (2015-05- 06) and 01E (2015-07- 16)

BSS10069 Synchronized BSS

• Chapter has been updated.

BSS20371 BSS Site Synchronisation Recovery Improvement


BSS11073 Recovery for BSS and Site Synchronisation


RG301965 GPS 1PPS+TOD Sync Support

• Chapter has been added.

Changes between issues 01C (2015-03- 26) and 01D (2015-05- 06)

BSS21439 Packet Abis Sync. ToP IEEE1588v2


Summary of changes Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

10 DN09167685 Issue: 01F



1 Overview of features in Flexi Multiradio BTSsoftware release GF1

Operating and Application SW

Nokia RG30(BSS) software consists of Operating Software and Application Software:

• Operating Software refers to basic functionalities of a product.

• Application Software refers to optional features.

The RG30(BSS) system features are available in the S16.1 and EX4.2 network element

releases.

g In this document, the RF Modules FXDA, FXDJ, FXEA, FXCA, and FXFA/ FXFB are

referred to as 70 W RF Module variants. RF Modules FXCB, FXDB, FXEB, and FXFC

are referred to as 90 W RF Module variants.

g In this document, the RRH Modules FHDA and FHEA are referred to as 2x40 W RRH.

FHDB and FHEB variants are referred to as 2x60 W RRH.

g Feature parity level with EX is only EX4.2 MP1.

For more information on the features, see Nokia GSM/EDGE BSS, rel. RG30(BSS),

operating documentation.

For general guidelines related to licensing, see Licence Management in BSC in the

GSM/EDGE BSS operating documentation.

Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

Overview of features in Flexi Multiradio BTS softwarerelease GF1

Issue: 01F DN09167685 11



2 Data/Voice

2.1 BSS20088 Dual Transfer Mode

Dual Transfer Mode (DTM) provides mobile users with simultaneous circuit-switched

(CS) voice and packet-switched (PS) data services. This means that users can, for

example, send and receive e-mail during an ongoing phone call.

In dual transfer mode, the mobile station (MS) is simultaneously in dedicated mode and

in packet transfer mode, so that the timeslots allocated for each MS are consecutive and

within the same frequency.

Benefits

With DTM, the operator can expand the service portfolio to offer users enhancedservices in a GSM/EDGE network. DTM allows the operator to provide a wide range of

services that demand a simultaneous CS and PS connection. Mobile users can use data

services, such as file transfer, web browsing, video sharing, and mobile net meeting,

during a speech call. This makes it possible to launch services similar to UMTS class A

services also in 2G networks. In addition, these services can be used to complement the

3G coverage in places where there is no 3G network coverage.

BTS functionality support

The BTS supports DTM through the normal BTS support of CS and PS services.

Interaction with other featuresDTM supports all full rate speech codecs. The CS speech codec selection for DTM is

similar to the selection mechanism used for a plain CS connection. In addition, the DTM

PS channels can be multiplexed in a similar way to normal GPRS/EDGE.

For more information on Dual Transfer Mode (DTM), see BSS20088: Dual Transfer

Mode document.

2.2 BSS9006 General Packet Radio Service (GPRS)

General Packet Radio Service GPRS provides packet radio access for GSM mobile

stations.

By sharing the channels provided by various network elements and transmission

systems, the cellular network resources are used more efficiently for data services than

with circuit switched data services.

All mobile stations share the radio resources in a cell, and use the radio resources only

when sending or receiving data.

The Channel Coding Unit (CCU) in the BTS performs the channel coding for the

following ETSI defined coding schemes:

• Channel Coding Scheme 1 (CS1) 9.05 kbit/s


Data/Voice Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

12 DN09167685 Issue: 01F





In packet transfer mode, the mobile station must use the continuous timing advance

procedure. This procedure is carried out on all packet data channels (PDCHs).

Coding Schemes CS3 and CS4 (BSS11088) is an application software product, and it

requires a valid license in the BSC. CS3 and CS4 provide a considerable gain in data

rates for GPRS mobile stations not supporting EGPRS (the mandatory RLC header

octets are excluded from the data rate values).

Link Adaptation (LA)

Flexi BTS supports PCU with GPRS link adaption by providing the measurements for the

uplink radio blocks.

Interaction with other features

CS3 and CS4 do not fit to one 16kbit/s Abis/PCU channel and require the use of

Dynamic Abis Allocation.

For more information on General Packet Radio Service (GPRS), see GPRS System

Feature Description document.

2.3 BSS10083 Enhanced General Packet Radio Service(MCS-1 - MSC-9)

Enhanced General Packet Radio Service (EGPRS) supports high rate packet dataservices across varying channel conditions. EGPRS is built on top of the packet switched

data service, GPRS. As the table below shows, EGPRS supports higher data rates

compared to the basic GPRS, using several Modulation and Coding Schemes (MCSs).

The speed in radio resources is fixed for Gaussian Minimum Shift Keying (GMSK) and 8

Phase Shift Keying (8PSK), but because the amount of channel coding varies, the user

data rate varies depending on the MCS.

Table 1 Peak data rates for single slot EGPRS

MCS

Modulation

Code Rate

Family

User Rate

MCS-1 GMSK .53 C 8.8 kbps

MCS-2 GMSK .66 B 11.2 kbps

MCS-3 GMSK .80 A 14.8 kbps

MCS-4 GMSK 1 C 17.6 kbps

MCS-5 8PSK .37 B 22.4 kbps

MCS-6 8PSK .49 A 29.6 kbps

MCS-7 8PSK .75 B 44.8 kbps


Data/Voice

Issue: 01F DN09167685 13



Table 1 Peak data rates for single slot EGPRS (Cont.)

MCS

Modulation

Code Rate

Family

User Rate

MCS-8 8PSK .92 A 54.4 kbps

MCS-9 8PSK 1 A 59.2 kbps

GMSK modulation provides the robust mode for wide area coverage, while 8PSK

provides higher data rates.

The MCSs are organized into families to allow a re-segmentation of the data block for

link adaptation. Since higher protection means lower throughput, the protection that best

fits the channel condition is chosen for maximum throughput.

Incremental Redundancy (IR)

Incremental Redundancy (IR) is an efficient combination of two techniques: Automatic

Repeat ReQuest (ARQ) and Forward Error Correction (FEC). In the ARQ method, when

the receiver detects the presence of errors in a received data block, it requests a re-

transmission of the same data block from the transmitter. The process continues until an

uncorrupted copy reaches the destination. The FEC method adds redundant information

to the user information at the transmitter, and the receiver uses the information to correct

errors caused by disturbances in the radio channel.

In the IR scheme (also known as Type II Hybrid ARQ scheme), only a small amount of

redundancy is sent first, which yields a high user throughput if the decoding is

successful. However, if the decoding fails, a re-transmission takes place according to the ARQ method. Using IR, the re-transmission of the data block is different from the initial

transmission. The transmitter sends additional redundancy that is decoded at the

destination with the previously received information to allow for error correction. Since

the combination includes more information than any individual transmission, the

probability of correct reception is increased.

The IR mechanism in EGPRS is designed around nine Modulation and Coding Schemes

(MCSs). The basic characteristics of each MCS are its fixed data rate and fixed

protection level. For each of the MCSs, it is possible to reach the same data rate with the

same protection level, but with a different protection scheme.


14 DN09167685 Issue: 01F



Figure 1 Incremental Redundancy scheme

Data Block

One MCS

P2 P3P1

P2

P2

P2

P1

P1

P1

P1

Stored

Stored

Receiver

Transmitter

No data

recovered

No data

recoveredCombination: Protection Level x 2

Protection Level 1

Combination: Protection Level x 3

Stored

P3

P3

1st transmission 1st re-transmission

upon reception failure2nd re-transmission

upon reception failure

There are three protection schemes (P1, P2 and P3) for an MCS, as shown in the figure

above. The data block is first protected with the P1 of a certain MCS, and sent over theair to the receiver, which tries to recover the data. If this phase fails, the received P1 is

stored in the receiver's memory for future use, and the transmitter sends the data block

protected with the P2 of the same MCS. The receiver combines the received P2 with the

stored P1 and tries to recover the data from the combination of P1 and P2. This process

continues until the data is recovered.

If after P3, the data still cannot be recovered, P1 is sent again and combined with the

stored P1, P2 and P3 (which reaches a protection level of about four times P1), and so

on until the data is recovered.

Link Adaptation (LA)

Flexi Multiradio BTS supports PCU with EGPRS link adaption by providing themeasurements for the uplink radio blocks.


EGPRS Modulation and Coding Schemes MCS-1 - MCS-9 require the use of Dynamic

Abis Allocation.


Data/Voice

Issue: 01F DN09167685 15



2.4 BSS7003 High Speed Circuit Switched Data and

BSS7037 14.4 kbit/s Data ServicesHigh Speed Circuit Switched Data uses multiple parallel channels to provide higher data

rates for end-user applications, such as the World Wide Web, file transfer and facsimile.

The BSS implementation is to reserve a multiple set of basic resources for one high

speed data call. The data rate and the number of reserved timeslots vary between one

and the defined maximum of the user application. The variable rate is needed for various

common procedures, for example for handovers to a new cell if the requested data rate

cannot be given immediately. The BSS implementation of HSCSD supports the

simultaneous usage of a maximum of four radio timeslots (RTSLs) per HSCSD call.

The table below presents the corresponding maximum data rates with different channel

coding.

Table 2 Corresponding maximum data rates with different channel coding

Number of RTSLs

9.6 kbit/s

14.4 kbit/s

1 9.6 kbit/s 14.4 kbit/s




Both asynchronous and synchronous bearer services and transparent and non-

transparent data services are supported. Transparent HSCSD uses fixed data rate

throughout the duration of the call, but with non-transparent HSCSD, the data rate can

be changed automatically during the call, because of increased traffic for example. The

radio interface is either symmetric or asymmetric according to the mobile station (MS)

capability.

During basic channel allocation, the system tries to keep consecutive timeslots free for

multichannel HSCSD connection. If there are not enough appropriate free channels to

fulfill the requested data rate, a non-transparent HSCSD connection is started with fewer channels than requested. At least one channel is allocated for a non-transparent HSCSD

call request if there are available resources in the cell. By use of the resource upgrade

procedure, the data rate of the HSCSD connection can be increased when an

appropriate channel is available.

In a congested cell, the HSCSD load can be adjusted by BSC parameterization. The

resource downgrade procedure is used to lower the HSCSD connection data rate to

release radio channels for other connections. If a transparent connection cannot be

established in a cell, a directed retry can be attempted.


16 DN09167685 Issue: 01F



BSS7037 14.4 kbit/s GSM Data Services

With the 14.4 kbit/s GSM Data Services, the speed of one timeslot increases from 9.6

kbit/s to 14.4kbit/s.

The 14.4 kbit/s channel coding has less error correction than 9.6 kbit/s coding.

Therefore, there are some areas on the cell edges where using 9.6 kbit/s coding will give

a higher data throughput. The figure below shows the results of simulations. Note that for

transparent mode the maximum user throughput is 14.4 kbit/s, but in non-transparent

mode, the maximum user throughput is 13.2 kbit/s. The maximum throughput is based

on the amount of available space in the coding block. Non-transparent data requires

space for error checking, but transparent data does not.

Figure 2 Typical data throughputs for 14.4 kbit/s (non-transparent) and 9.6 kbit/scoding (this depends on the NW radio conditions)

0

2

4

6

8

10

12

14

60 65 70 75 80 85 90 95 100

Percentage of Cell Area (%)

D a t a T h r o u g h p u t R a t e ( k b i t / s )

14.4

9.6

The Automatic Link Adaptation (ALA) optimizes the data throughput by automatically

choosing the channel coding most suitable to the radio conditions and by control of the

power levels.The 14.4 kbit/s Data Services can be combined with High Speed Circuit Switched Data

(BSS7003).

Note that Flexi BTS does not support transparent data handovers because of limitations

in fax protocols.

2.5 BSS10004 Adaptive Multi Rate Codec (AMR)

Adaptive Multi Rate Codec provides significantly better speech quality by:

• using better source coding algorithms that give better subjective speech quality for the same link capacity

• adaptively adjusting ratio of bits used for speech coding and channel coding to

always provide best subjective speech quality according to current radio conditions.

With AMR it is possible to increase speech capacity by using HR mode and still maintain

the quality of current FR calls. It consists of an adaptive algorithm for codec changes and

8 different speech codecs (14 codec modes) listed in the table below.


Data/Voice

Issue: 01F DN09167685 17



Table 3 Channel and speech codec modes for AMR

Channelmode

Channelcodec mode

Sourcecoding bit-

rate, speech

Net bit-rate,in-band

channel

Channelcoding bit-

rate, speech

Channelcoding bit-

rate, in-band

TCH/FR CH0-FS

CH1-FS

CH2-FS

CH3-FS

CH4-FS

CH5-FS

CH6-FS

CH7-FS

12.20 kbit/s

(GSMEFR)

10.20 kbit/s

7.95 kbit/s

7.40 kbit/s

(IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s

4.75 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

10.20 kbit/s

12.20 kbit/s

14.45 kbit/s

15.00 kbit/s

15.70 kbit/s

16.50 kbit/s

17.25 kbit/s

17.65 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

0.30 kbit/s

TCH/HR CH8-HS

CH9-HS

CH10-HS

CH11-HS

CH12-HS

CH13-HS

7.95 kbit/s (*)

7.40 kbit/s

(IS-641)

6.70 kbit/s

5.90 kbit/s

5.15 kbit/s4.75 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

3.25 kbit/s

3.80 kbit/s

4.50 kbit/s

5.30 kbit/s

6.05 kbit/s

6.45 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

0.10 kbit/s

(*) Not supported, requires 16 kbit/s TRAU.

Codec mode adaptation for AMR is based on received channel quality estimation in both

the mobile station (MS) and the BTS.

The BTS and MS inform and request of codec used/to be used by in-band signaling. For

more information on Adaptive Multi Rate Codec, see BSS10004 and BSS6071:

Enhanced Speech Codecs: AMR and EFR document.

2.6 BSS7005 Intelligent Frequency Hopping andBSS6114 Intelligent Underlay-Overlay

With Intelligent Frequency Hopping and Intelligent Underlay-Overlay, it is possible to

reuse frequencies more intensively, and therefore achieve a higher radio network

capacity. With Intelligent Frequency Hopping, it is also possible to avoid frequency

dependent fading on the radio path.

When Intelligent Frequency Hopping is in use, the operator can use Intelligent Underlay-

Overlay simultaneously with frequency hopping in the same cell. Either baseband (BB)

or radio frequency (RF) hopping can be used.


18 DN09167685 Issue: 01F



The different interference characteristics of the regular and super-reuse layers in

Intelligent Underlay-Overlay require that the network plan for frequency hopping is

constructed separately for each layer. Intelligent Frequency Hopping enables the use of

separate Mobile Allocation Frequency Lists of radio frequency hopping for the layers of

an Intelligent Underlay-Overlay cell. Baseband hopping is implemented by treating the

regular layer as a normal cell and the super-reuse layer as a new hopping group.

The operator can set the regular and super-reuse layers in Intelligent Underlay-Overlay

individually to hopping.

For more information on Intelligent Underlay-Overlay, see Intelligent Underlay-Overlay

document.

2.7 BSS20960 Wideband AMR and BSS21118 TFO for

AMRThese features introduce wideband AMR coding as specified by 3GPP and ITU-T.

Wideband AMR is based on a family of new speech codecs. It is designed to achieve

improvements in speech quality. The sampling rate of WB AMR speech codec is

increased to 16 kHz which allows the bandwidth of the signal encoded to be extended to

cover range from 50 to 7000 Hz. Wideband AMR requires end to end tandem free

operation support. For more information on these features, see the document

BSS20960: Wideband AMR and BSS21118: AMR TFO.

2.8 Long Reach TCH TSL

A new RTSL type, Long Reach TSL, is used temporarily for incoming external handovers

(from 2G or 3G) in order to allow the BTS to determine the cell area (normal or

extended) where the mobile is actually located. The BTS informs the correct area to the

BSC which starts an intra-cell handover to this area.

2.9 BSS101482 Extended Cell functionalities for FlexiMultiradio BTS

Flexi Multiradio BTS supports extended cell features from EX4.1 onwards. The BSC

allows the user to configure these features for use in Flexi Multiradio BTS. The featurehas no separate license and the existing Flexi EDGE license applies for Flexi Multiradio

BTS.

Benefits

Extended Cell Range increases the cell radius to about 105 km, which means that this

kind of extended cell covers an area that is much larger than an ordinary cell, thereby

reducing CAPEX. The feature provides continuous support for upgrading the Flexi

Multiradio BTS with EX4.1 or later versions.


Data/Voice

Issue: 01F DN09167685 19



BSS20882 Extended Cell Range for CS

The cell radius of an ordinary cell is 35 kilometers. Extended Cell Range increases the

cell radius to about 70 km. The implementation is based on a one-BCCH and two-TRX

solution. Timing of the TRXs that serve the extended coverage area is delayed so thatthey can serve the area beyond 35 kilometers. The extended coverage area is served

with different TRXs than the normal coverage area and the TRXs so configured are

referred to as Extended TRXs (E-TRX).

BSS20094 Extended Cell support for GPRS/EDGE

Extended cell for GPRS/EDGE has been built on top of the extended cell function. This

means that the same method is used for creating the normal and extended service

areas, and the same parameters are used for dimensioning the cell for both PS and CS

services.

The two service areas are part of the same cell and both areas are served by the same

BCCH. In practice this means that MS movement between the service areas is handledas intra-cell reallocation instead of cell re-selection.

Only the BCCH BTS of an extended cell may serve the extended service area, that is,

the TRXs serving the extended service area must be accommodated by the BCCH BTS.

The minimum extended cell configuration includes two TRXs – one for the extended

service area and one for the normal service area – but multiple TRXs may be used in

both service areas.

Implementation

The extended cell implementation is based on one-BCCH and two-TRX solution.

Different TRXs serve the normal and the extended area. The TRX, which serves the

normal area, is normally configured with the BCCH/SDCCH and TCHs. The timing of thereceiver of the TRX which serves the extended area (E-TRX) has been delayed so that it

can serve the area beyond 35 kilometres. The timeslot 0 of E-TRX is tuned to the BCCH

frequency in order to get RACH-bursts from the extended area. The timing of

transmitters is the same in both TRX and E-TRX. If more capacity is required either in

the normal area or extended area, more TRXs can be added to serve those areas.

• The Extended Cell Range for Flexi EDGE BTS is supported for all Flexi frequency

bands.

• MHA units should be used in the Flexi EDGE BTS configuration to ensure

transmitted signal strength can reach the maximum range.


The following features cannot be used simultaneously with the Extended Cell Range for

Flexi EDGE BTS:

• Baseband hopping

• RF hopping cannot be used in extended area TRXs (RF hopping can be used in

normal area non-BCCH TRX(s), if present)

• Antenna hopping

• Intelligent Underlay Overlay (IUO)

• Dynamic Frequency Channel Allocation (DFCA)

• TRX Test: TRX Test cannot be commanded for a TRX configured to cover the

extended outer area


20 DN09167685 Issue: 01F



Benefits for the Operator

The extended cell feature is best suited for applications in coastal areas, rural areas and

corresponding ones where coverage exceeds typical GSM maximum cell size of 35 km.

Capex and Opex savings by enlarging cell areas and reducing number of radio sites

improved end user experience by having wider coverage Extended cell for GPRS/EDGE

feature is best suited for configurations in coastal and rural areas where coverage

exceeds typical GSM maximum cell size of 35 km.

BSS21270 105 km Extended Cell and BSS21277 105 km ExtendedCell for GPRS/EDGE

BSS21277 and BSS21270 are optional features and those can be used with Flexi-

Multiradio BTS to increase the cell radius to about 105 km. The cell radius in a normal

cell is 35 km, and the cell radius of the extended cell is 70 km. The cell with a 105 km

radius is referred to as a super-extended cell.105 km extended cell features have been

built on top of the extended cell function.

This feature expands the maximum extended cell radius to 105 km by allowing TRX

reception to be delayed further (up to 80% of a TSL duration) in relation to TRX

transmission. The TRXs so configured are referred to as super extended TRXs (S-

TRXs). This feature concerns only CS services.


The following features cannot be used simultaneously with features BSS21277 and

BSS21270:


•

RF hopping cannot be used in extended/super extended are TRXs (RF hopping canbe used in normal area non-BCCH TRX(s), if present)

• Antenna hopping

• Intelligent Underlay Overlay (IUO)

• Dynamic Frequency Channel Allocation (DFCA)

• TRX Test: TRX Test cannot be commanded for a TRX configured to cover the

extended/super extended outer area


Capex and Opex savings by enlarging cell areas and reducing number of radio sites

improved end user experience by having wider coverage Extended cell for GPRS/EDGE

feature is best suited for configurations in coastal and rural areas where coverage

exceeds typical GSM maximum cell size of 35 km.

BSS21274 Long Reach TSL (2G BTS)

Normally the BSC attempts to allocate incoming external handovers always to E-TRXs in

extended cells, however, it is possible that the mobile is actually located in the normal

coverage area of the target cell. In this case the handover would fail. The long reach

timeslot feature addresses this scenario.

Requirement

The features are supported with RG20(BSS) EP1


Data/Voice

Issue: 01F DN09167685 21



2.10 BSS21388 Random Fill Bits

This new feature provides an additional security enhancement for the generally

employed A5/1 ciphering solution as well as the A5/3 security mechanism and mitigates

the risks associated with a potential 'cracking' of the standard A5/1 mechanism, which

employs a fixed pattern filling bits sequence.


Whilst the A5/3 ciphering solution provides the required level of security against the

'cracking' of the standard A5/1 ciphering mechanism, near-full penetration of supporting

handsets is not available currently in today's networks. Consequently, this feature

provides another essential enhancement for the existing A5/1 ciphering mechanism in

cases where the A5/3 solution cannot be employed. This feature may also be used to

enhance the A5/3 ciphering mechanism and thus security.

Functional Description

In general, the A5/3 ciphering solution has been released and ultimately provides the

required level of security against this problem. However, since A5/3 capable handsets

currently do not represent the majority in general field deployments, this enhancement to

the A5/1 solution mitigates the immediate issue for Operators. The solution itself has

arisen from fears concerning the co-ordinated efforts into the real-time 'cracking' of the

generally employed A5/1 ciphering security mechanism. If a frame contains a length

indicator with value less than N201, the frame contains fill bits. Currently, the fixed

sequence '00101011' is employed for these fill bits. With this new feature, excluding the

first octet which still uses the fill bits '00101011', each subsequent fill bit shall be set to a

random value when sent by the network for either the A5/1 or A5/3 encryption

mechanism. A new activation parameter (acting at the cell level) is introduced. The

default value is that the feature is not activated. This feature may be used in combination

with BSS21389 or separately, as required.

Requirements

• The feature is supported with RG20(BSS) EP1

• The feature is supported via NetAct release OSS5.2 MP1

• The feature (and licence key for) BSS21389, A5/1 Cipher Enhancement - SDCCH

HO. The features may be activated independently of one another.

2.11 BSS21309 OSC Half Rate with SAIC MS

“Orthogonal subchannel (OSC)” is a feature that increases the radio channel capacity for

voice calls in GSM networks. This is provided by adopting quadrature phase shift keying

(QPSK) in downlink and orthogonal subchannels in uplink. These two key techniques

linked with adaptive multi rate (AMR) make it possible to serve two users that support

single antenna interference cancellation method (SAIC) simultaneously, in the single

radio traffic channel. The increase in network capacity depends on the radio conditions.

The feature “BSS21309 OSC Half Rate with SAIC MS” implements the OSC feature for

Half Rate traffic channels. With this feature, four users can share the same radio timeslot

with SAIC and AMR support from the mobile station. When OSC Half Rate with SAIC MS

is used, an increased Abis transmission capacity is required because OSC Half Rate


22 DN09167685 Issue: 01F



calls are multiplexed into one Half Rate traffic channel (TCH/H). The increased Abis

transmission capacity is provided by circuit switched dynamic Abis pools (CSDAPs) or

packet Abis.

OSC Half Rate with SAIC MS is an application software feature controlled by licensing.For detailed description of this feature, see BSS21309: OSC Half Rate with SAIC MS

Feature Description document.

This feature provides the following benefits:

• The feature is applicable with existing GSM SAIC handsets, thus providing an

immediate gain with just a software upgrade in the GSM radio network

• It increases the capacity for voice and releases capacity for data traffic without

requiring new TRXs or related hardware. This reduces the number of TRXs required

to realize a specific capacity or spectral efficiency

• The increased capacity per TRX reduces the energy consumption per user. This

reduces the energy consumption required per Erlang significantly

• It avoids the need to add new sites, as it maintains the coverage area in capacity

extensions

• The increased capacity per TRX effectively reduces site density through reduced

combining losses

• When another radio technology needs to share the same site, antennas or input

ports of combiners may be released by the introduction of OSC Half Rate with SAIC

MS


The “BSS21309 OSC Half Rate with SAIC MS” feature has the following limitations with

these features:

• 4-way uplink diversity

The BSC does not apply DHR multiplexing in a TRX that has 4-way uplink diversity

(4UD) feature in use.

• Dynamic Frequency and Channel Allocation

The BSC does not support Double Half Rate with SAIC MS feature in the TRXs that

apply the Dynamic Frequency and Channel Allocation (DFCA) feature.

• Extended Cell Range

DHR multiplexing is not applied in the TRXs of the extended coverage area.

• Super Extended Cell Range

OSC is not supported in the TRXs of the Super Extended coverage area.

• Intelligent Downlink Diversity

The BSC does not apply DHR multiplexing in a TRX that has Intelligent DownlinkDiversity (IDD) feature in use.

• Rx diversity

Use of Double Half Rate requires that the Rx diversity feature is also in use.

Recommendation

Some handset types may not perform equally good with few of the available training

sequence pairs. If OSC capacity is critical for a particular cell, then TSC pairs (1, 7) and

(5, 6) should be avoided to maximize the cell capacity with OSC.

Requirements

• BSC S15


Data/Voice

Issue: 01F DN09167685 23



• Flexi EDGE BTS EX4.0, Flexi Multiradio BTS EX4.1 or Flexi Multiradio 10 BTS

GF1.0

• NetAct OSS5.2 CD SET 3

• MS Capable of SAIC and AMR

2.12 BSS21534 OSC Full Rate with SAIC MS

The feature, BSS21534: OSC Full Rate with SAIC MS (also referred as Double Full Rate

or DFR) serves two AMR FR calls on SAIC capable handsets simultaneously on single

full rate traffic channel in a similar way as the feature, Double Half Rate with SAIC MS

(DHR) serves two AMR HR calls on SAIC capable handsets simultaneously on single

half rate traffic channel.

OSC Full Rate is an optional feature controlled by using an On-Off license and a

capacity license. BSS21534 OSC Full Rate with SAIC MS (Activation License) is anON/OFF license and provides an initial capacity of 100 simultaneous DFR Pairs.

BSS402011 OSC Full Rate Capacity License provides additional capacity in blocks of

100 DFR Pairs.

In a configuration, where a BTS has the OSC Full Rate feature enabled the BSC allows

unlocking of the BTS in question only if the OSC Full Rate with SAIC MS feature’s state

is ON. The use of OSC Full Rate feature is controlled with a BTS object parameter in the

BSS RNW Configuration Database.

The BSC requires that a BTS object is in the locked state in order to allow enabling or

disabling OSC Full Rate in the BTS. The enabling of OSC Full Rate feature results in

modifying the parameter Limit for Triggering OSC DFR Multiplexing from 0 to a value

greater than 0. The disabling of OSC Full Rate feature means modifying the parameter from a value greater than 0 to 0.

Having the parameter on BTS level allows the BTS specific control of the feature in

segment configuration where the operator can apply different policies for different layers

of a segment.

Recommendation

Some handset types may not perform equally good with few of the available training

sequence pairs. If OSC capacity is critical for a particular cell, then TSC pairs (1, 7) and

(5, 6) should be avoided to maximize the cell capacity with OSC.

Requirements

• BSC S15 EP1.2


GF1.0

• NetAct OSS5.2 CD SET 3

• MS Capable of SAIC and AMR

2.13 BSS21325 8k TRAU for OSC AMR FR

The feature, BSS21325: 8k TRAU for OSC AMR FR allows two AMR FR calls

multiplexed as OSC using fixed transmission capacity allocated for a single Radio TSL inlegacy Abis.


24 DN09167685 Issue: 01F



Two OSC AMR FR calls can be supported within legacy Abis transmission allocated for a

single radio timeslot (that is 2*8kbit/s Abis timeslot) when 8kbit/s TRAU frames are used

on Abis. When 8K TRAU for OSC AMR FR feature is enabled AMR codecs are restricted

up to 7.4K within the codecs used in the active codec set (ACS). The OSC-0 call is

supported in the first half of the Abis timeslot and the OSC-1 call is supported in the

second half of the Abis timeslot.

The feature, BSS21325: 8k TRAU for OSC AMR FR is optional with ON/OFF type

license. The 8k TRAU for OSC AMR FR can be activated independently from OSC Full

Rate with SAIC MS (BSS21534) and Circuit Switched Dynamic Abis Pool (BSS30385)

features.

The BSC specific ON/OFF license controls the availability of the 8k TRAU for OSC AMR

FR feature. The usage of this feature is controlled with a new BTS level parameter, 8k

TRAU for DFR Enabled. This parameter enables the DFR multiplexing in 8k TRAU

mode. It also defines the preference in selection between CSDAP and 8k TRAU mode

for DFR calls.

Requirements

• BSC S15 EP1.2


GF1.0

2.14 BSS21313 OSC support for VAMOS handsets

Voice services over adaptive multi-user channels on one slot (VAMOS) is a 3GPP

standardized feature, which allows the multiplexing of two users simultaneously on the

same physical resource in the circuit switched mode both in downlink and in uplink, using

the same timeslot number and TDMA frame number. OSC is Nokia proprietary feature

for VAMOS. OSC support for VAMOS Handsets feature is extension to OSC in which the

BSC supports the Training Sequence Code Set 2 (TSC Set2) and VAMOS mode

indication functionality.

The two classes of standardized VAMOS handsets are:

• VAMOS 1 supporting new training sequences, called TSC set2, and having DL SAIC

(or DARP phase I) receiver.

• VAMOS 2 supporting new training sequences, called TSC set2, and having

advanced receiver architecture than that of VAMOS 1.

The feature ‘BSS21313 OSC support for VAMOS handsets’ implements support for new

training sequences (TSC set2) for handsets indicating VAMOS capability. This feature is

an enhancement of basic OSC features BSS21309 Orthogonal subchannel with SAIC

MS and BSS21534 OSC Full Rate to extend support for new VAMOS 1 and VAMOS 2

handsets. This feature is controlled by an ON/OFF license.

Implementation

TSC set2 is selected for VAMOS capable calls even in normal non-paired TCH allocation

to increase the pairing probability for SAIC-VAMOS pairs. In case of SAIC-VAMOS pairs,

if the first multiplexing candidate is VAMOS capable and uses TSC set1 and second

multiplexing candidate is SAIC capable which doesn't support TSC set2, the pairing of

these mobiles is not possible since TSC of first candidate cannot be changed during


Data/Voice

Issue: 01F DN09167685 25



multiplexing. The VAMOS-SAIC pairing where first multiplexing candidate is VAMOS

capable is possible only if this VAMOS capable candidate is using TSC set2. When OSC

pair is selected:

• First candidate call maintains the same TRX, TSL and OSC subchannel, andcurrently used TSC code.

• Second candidate call is moved to the target radio channel (to other OSC

subchannel) with intra cell handover, and its TSC code is set according to the

following rules:

– TSC (set1, set1) in case of legacy SAIC-legacy SAIC OSC pair

– TSC (set1, set2) or TSC (set2, set1) in case at least one handset is VAMOS

capable. Handset using TSC set2 has to be VAMOS capable.

To support OSC for VAMOS, the OSC multiplexing has been enhanced to take

into account the different types of handsets in OSC pairing and TSC selection.

• First candidate selection and second candidate selection shall consider not onlylegacy SAIC handsets but also VAMOS 1 and VAMOS 2 handsets can be included.

For more details, please refer the below feature description documents:

• BSS21309 Double Half Rate with SAIC MS

• BSS21534 OSC Full Rate with SAIC MS

• BSS21537 AQPSK with VAMOS 2 Handsets

Benefits

• ‘OSC support for VAMOS handsets’ feature provides better performance in UL and

DL for VAMOS pairs due to the usage of new training sequence codes (TSC set2),

as new TSCs have low cross-correlation with legacy TSCs.• VAMOS 2 capable mobiles have better performance in DL, as they have more

advanced receiver than SAIC.

Requirements

• BSC S16

• Flexi Multiradio BTS EX5.1 or Flexi Multiradio 10 BTS GF1.0

• NetAct OSS5.4

• MS Capable of VAMOS (VAMOS 1 or VAMOS 2)

2.15 BSS21537 AQPSK with VAMOS 2 Handsets

'AQPSK with VAMOS 2 Handsets' feature extends Orthogonal Subchannel (OSC)

support for non-SAIC handsets when paired with VAMOS 2 capable handsets with the

support of AQPSK modulation in downlink. This feature includes the support of DL

AQPSK modulation creating quaternary constellation using fixed static alpha parameter.

Alpha parameter gives the gain obtained on higher power subchannel compared to

equally powered (QPSK modulated) subchannels and is dependent on used phase

rotation. For more details see the AQPSK constellation figure.

The feature BSS21537: AQPSK with VAMOS 2 Handsets is controlled by an ON/OFF

license.


26 DN09167685 Issue: 01F



AQPSK modulation together with advanced receiver performance of VAMOS 2 handset

allows BTS to use OSC sub channel specific power for a non-SAIC – VAMOS 2 pair.

BTS and TRX needs to support AQPSK modulation before BSC can multiplex a non-

SAIC handset with a VAMOS 2 handset. The non-SAIC handset of the OSC pair gets

downlink boost when it is allocated to the higher power sub channel whereas VAMOS 2

handset of the same OSC pair can survive in the lower power sub channel because of its

advanced receiver performance. AQPSK modulation is applied when non-SAIC and

VAMOS 2 handset are multiplexed and when the pair is demultiplexed, modulation is

changed to GMSK for the remaining connection.

DL AQPSK modulation creates quaternary constellation using fixed static alpha

parameter. Alpha parameter gives the gain obtained on higher power subchannel

compared to equally powered (QPSK modulated) subchannels. Alpha value = 1.3 is the

only value supported by this feature. VAMOS 2 mobiles are supposed to be based on

architectures that would enable better detection of the subchannel signal at lower

subchannel power imbalance ratios (SCPIRs). AQPSK modulation creates quaternary

constellation using phase rotation f, as shown in below figure.

Figure 3 AQPSK constellation

ORTHOGONAL SUB CHANNEL ACTIVATION FAILURE Alarm

BSC raises ORTHOGONAL SUB CHANNEL ACTIVATION FAILURE alarm for the BTS

when consecutive OSC channel activation failures take place during multiplexing in a

TRX in OSC DHR and OSC DFR features. BSC uses the same procedure and the same

rules when AQPSK modulation is involved in multiplexing. A supplementary information

field is added to the alarm to display AQPSK modulation involvement in failed

consecutive OSC multiplexing attempts. The supplementary information field is set when

AQPSK modulation has been involved at least in one of the failed consecutive OSC

multiplexing attempts that trigger the OSC channel activation failure alarm. AQPSK

modulation information in the alarm provides a way to see if AQPSK modulation

increases consecutive OSC channel activation failures.

Benefits


Data/Voice

Issue: 01F DN09167685 27



• OSC support can be provided to non-SAIC handsets to increase the network voice

capacity.

Requirements

• BSC S16 or later


• NetAct OSS5.4 CD Set 2 or later

• MS Capable of VAMOS 2, AMR and Non-SAIC AMR

2.16 RG301666 EGPRS Downlink Power Control

The EGPRS Downlink (DL) Power Control feature helps in controlling the downlink

transmit power on EGPRS timeslots and decreasing the interference that is caused due

to progressive introduction of packet switched services in GSM networks.

DL power control initially starts from maximum power and adjusts power so that the

target BEP or C/I levels can be maintained. The power control in DL transmission is

done on a block-by-block basis depending on the receiver’s channel conditions. If a

Mobile Station (MS) is in good radio conditions, the DL transmit power for the MS can be

reduced. If the MS is in bad radio conditions, then the DL transmit power for this MS can

be increased. This not only reduces interference in the radio network, but also reduces

BTS Power consumption.

g DL power ctrl can only be applied when dedicated PS data blocks are sent to exactly

one MS.

In the existing Abis L1 interface the DL PCU (master) data frames contain a Downlink

Power Control field which indicates the DL power level to BTS. Currently, PCU sets this

field based on PMAX (= maximum power level on the TRX) and the value is not changed

unless the parameter value is changed by the operator.

With the Downlink Power Control for EGPRS DL Power Control feature, PCU controls

the DL transmit power with the same field but now the field value is changed on a block-

by-block basis based on a pre-defined algorithm using which the PCU sets the DL power

level for each DL RLC block. The BTS sets the DL transmit power on a block-by-block

basis based on the Downlink Power Control field.

The key parameters for the Downlink Power Control field for the EGPRS DL Power

Control feature are:

• Initial DL power (-4 dB)

• Minimum DL Power (Pmax-8 dB)

• Target BEP for EGPRS (29)

• Target C/I for GPRS (14 dB)

Benefits

The EGPRS DL Power Control feature provides the following benefits to the operator:

• It reduces transmit power, which in turn helps in reducing the interference in the

network, and hence the mobiles experience better radio conditions.

• It helps in reducing BTS power consumption.


28 DN09167685 Issue: 01F



• It maintains voice quality when the data usage increases.

2.17 BSS21542 OSC Capability Test for Handsets'OSC Capability Test for Handsets' feature increases and improves utilization of

BSS21309: OSC Half Rate with SAIC MS and BSS21534: OSC Full Rate with SAIC MS

features available in the BSC.

Handsets that do not indicate Single Antenna Interference Cancellation (SAIC) support

to the network are tested with a momentary Quadrature Phase-Shift Keying (QPSK)

transmission. Handsets that clear the test are regarded as OSC capable and are

candidates for OSC multiplexing. This way the utilization of OSC is increased in the

network. OSC reliability is checked to ensure OSC capability of handsets. If the DL RX

quality of a handset decreases drastically after OSC multiplexing then the handset is

regarded as non OSC capable by the BSC. This improves the quality of the network.

OSC Capability Test for Handsets is an optional feature that is controlled with BSC

license key, ON/OFF. Test for Handsets is as below:

• Handset Selection

• OSC Capability Test

• RX Quality Report Generation and Inference

Figure 4 OSC Capability Test for Handsets

MS BTS BSC

Boosted speech over QPSK

CHANNEL ACTIVATION(OSC test information)

Measurement report

Measurement Result(OSC test IE)

Handset Selection

BSC selects handsets that have to undergo OSC Capability Testing based on following

criteria:

• DARP capability not indicated in MS Classmark 3

• Revision level indicated in MS Classmark 1 and 2 is not GSM phase 1

• AMR codec has been selected for the TCH to be activated

• Emergency calls are not selected

• Handsets that are already tested are not selected


Data/Voice

Issue: 01F DN09167685 29



• Handsets whose channel activation is related to OSC multiplexing are not selected

BSC’s decision to test a handset is informed to BTS in Channel Activation message

OSC Capability Test

BTS decides when to start the OSC Capability Test. The decision is based on DL RX

quality reports received from the MS. If the reported downlink RX quality is equal to or

better than a new DL RX quality threshold for OSC capability test parameter, the test is

initiated.

BTS sends boosted QPSK over test period to probe handset’s OSC capability.

Test Report Generation and Inference

BSC determines handset OSC capability by comparing DL Rx Quality values from test

period to DL Rx Quality values prior to the test period. If DL Rx Quality remains

acceptable during the test period then BSC regards the handset as OSC capable. If DL

Rx Quality degrades to unacceptable level or BSC cannot complete the comparison thenit regards the handset as OSC incapable.BSC maintains handset OSC capability test

result until the end of the call or until the handset is handed over to other BSC.

Detecting and Handling of MS with Faulty SAIC Indicator

Handsets that indicate SAIC support to the network are regarded as non OSC capable

by the BSC if, the DL RX quality of these handsets decreases drastically right after OSC

multiplexing. In such a scenario, BSC does not select the handset again for multiplexing

for the remaining duration of the call.

Benefits

• The feature increases network capacity by increasing OSC utilization

• The feature improves network quality and reduces call drop rate by identifying SAICcapable MSs that cannot survive in OSC mode

Requirements

• BSC S16


• NetAct OSS5.4 CD Set 2

• MS capable of SAIC but not reporting and capable of non-OSC but SAIC reporting

2.18 RG602124 Composite Multi Site TransmissionIn Composite Multi Site Transmission feature, antennas at different locations are merged

into one single logical cell, or composite cell, which helps in reducing the inter-cell

handover. The BTS is connected to multiple antennas (nodes) that are not co-located. A

maximum of six nodes are allowed in one BTS. If the transmitting and receiving

antennas are chosen correctly for every connection, the coverage in the cell becomes a

union of coverage areas of individual antennas. This way, the coverage can be improved

without increasing the number of cells and the number of handovers. In order to

minimize inter cell handovers, the non-co-located antennas are merged into a single cell.

The feature reduces inter-cell handovers in, for example, multi-floor sites thereby

improving network performance.


30 DN09167685 Issue: 01F



g Note that maximum of 12 nodes are allowed in GF.

The user can travel from one node to another inside the logical cell without a handover.

Inter-cell handover is needed only when moving from one logical cell to another. When ahandover occurs inside a logical cell, the TRX id and TSL remain the same but the

composite node id changes. In order to avoid an accumulation of interference for CS

Channels, a single active transceiver node is selected - that with the best Uplink signal -

from the (up to) six nodes that are available. Additionally, one node for receiving (Uplink

Diversity) is also selected. The BCCH Channel and PS Services are broadcasted

through all nodes in the Downlink.

Figure 5 Composite cell concept in multi-floor solution

Cell 1

Cell 1

Cell 1

Cell 1

Cell 1

Cell 1

Cell 2HO

Cell 7

Cell 6

Cell 5

Cell 4

Cell 3

Cell 2

Cell 1Floor 1

Floor 2

Floor 3

Floor 4

Floor 5

Floor 6

Floor 7

HO

HO

HO

HO

HO

HO

Node 6

Node 4

Node 3

Node 2

GSM SM

Node 1

Node 5

a) Without Composite Multi Site Transmission b) With Composite Multi Site Transmission

For call set up and handovers, BTS informs the BSC about the antennas using Channel

Required and Measurement Result messages.

BSC provides the details received through these messages back to BTS in Channel

Activation message for relaying them to target cell BTS in call setup and in BSC internal

handovers when the feature is enabled. The BTS uses this information for correct

mobility management inside composite cell

Composite Multi Site Transmission feature is controlled with TRX based capacity license.

For Flexi Multiradio 10 BTS enhanced CMST feature, see RG301980 CMST Support

with FSM3.

Benefits

The Composite Multi Site Transmission feature provides the following benefits to

operators:

• It reduces the number of required cells since the composite cell has same area as

several individual cells.

• It improves the network performance due to less inter-cell handovers.

Restrictions

The following features can not be used with this feature:


Data/Voice

Issue: 01F DN09167685 31



• OSC Half Rate (BSS21309) and OSC Full Rate (BSS21534)

• DFCA (BSS11052) and DFCA Support for OSC (BSS21391)

• MCPA Tx Power Pooling (BSS21507)

• Intelligent Underlay Overlay (BSS04016), Handover Support for CoverageEnhancement (BSS07064), and Enhanced Coverage by Frequency Hopping

(BSS08037)

• Extended Cell (BSS101482) and super extended cell (BSS21270)

• Long Reach TSL (BSS21274)

• Multi Operator BSS (BSS21213)

• RF sharing GSM-LTE (BSS21520)

• RF sharing GSM-WCDMA

• Satellite Abis (BSS5850)

• Preferred BCCH mark is not recommended to use since BTS will internally control

with BTS_ALARM that BCCH is located to the TRX which is the best possible.

• Multi BCF (BSS10046) configuration is not allowed since BCF where CompositedMulti Site Transmission is activated can contain only one BTS object configuration.

• RX Diversity shall be enabled on segment where CMST is enabled (that is, no single

antenna support

2.19 RG602125 High Speed Rail Handover

In the feature RG602124 Composited Multi Site Transmission, up to six spatially

distributed Remote Radio Heads (RRH) are linked and synchronized into a single cell.

This reduces the number of handovers in the coverage area of Composited Multi Site

cell.. RG602125 High Speed Rail Handover is an enhancement of Composite Multi SiteTransmission feature, and provides more reliable mobility management in places where

existing handover features may not provide fast enough HO decisions for cell change.

Figure 6 CMST in railway environment

This feature provides a fast handover (HO) decision for a mobile station (MS) that is

travelling on a high speed train where the uplink signal level degrades rapidly. It

executes handover to one pre-defined GSM adjacent cell when the serving composite

cell coverage ends. It is possible to define one GSM target adjacent cell for each of the

composited multi site cell nodes. High Speed Rail handover to a pre-defined adjacent


32 DN09167685 Issue: 01F



cell is performed without any radio link measurements of the pre-defined adjacent cell.

Composite Multi Site Transmission feature is needed as a base to provide composite cell

structure. If High Speed Rail Handover is active, then RSSI part of Enhancement on

VSWR and RSSI feature is not supported. The feature is controlled with TRX based

capacity license.

For Flexi Multiradio 10 BTS enhanced CMST feature, see RG301980 CMST Support

with FSM3.

Benefits

• It provides fast handover decision towards a pre-defined adjacent cell.

• It provides successful mobility management by providing fast and reliable handover.

• It provides the MS with a speed of upto 450 km/hr on high speed train.

Restrictions

• In an HSR site when optical cable length between ESMx and FHxX is >10 km, Uplinksamples are not be received by DSP SW for TRX defined on FHxX(connected with

>10KM) but Downlink Transmission works fine from all the Nodes. This impacts the

TRX test and CS call.

Requirements

• BSC S16

• Flexi Multiradio BTS EX5 or Flexi Multiradio 10 BTS GF1.0


2.19.1 CMST configuration restrictions(BSC):

This section provides CMST configuration restrictions in BSC.

• All the neighbors equipped for a CMST cell should be configured as type

ASYNCHRONOUS.

g • A CMST configuration in a collocated BTS should be avoided.

• In case of a collocated BTSs, the CMST and non-CMST cells should not be defined

as SYNCHRONIZE neighbors otherwise this would result in Handover failure and

other unpredictable behavior.

Table 4 Logical TRX ID, number of TRXs, and total number of CMST cell nodes

CMST Nodes

Abis

TRX

ID

1

2

3

4

5

6

7

8

9

10

11

12

1 Supported Logical TRX_id = any of

(1,4,7,…,31,34); otherwise 7600 alarm at

start-up

Supported Logical trx_id = any of

(1,7,….31); otherwise 7600 alarm at start-

up7


Data/Voice

Issue: 01F DN09167685 33



Table 4 Logical TRX ID, number of TRXs, and total number of CMST cell nodes(Cont.)

CMST Nodes

Abis

TRX

ID

1

2

3

4

5

6

7

8

9

10

11

12

13

19

25

31

4 Invalid, disable any invalid TRXs, with 7606

alarm (BB resource not avalable) if a BCF

is already operational10

16

22

28

34

Table 5 Number of Logical TRXs and depth of single optical chain (number of RRHper optical chain)

RRH per RP3-01 link

Abis TRX

1

2

3

4

5

6

1

2

3

4

5

6


34 DN09167685 Issue: 01F



Table 5 Number of Logical TRXs and depth of single optical chain (number of RRHper optical chain) (Cont.)

RRH per RP3-01 link

Abis TRX

1

2

3

4

5

6

7

8 *

9 * *

10 * *

11 * *

12 * * *

* - 7600 (at startup) or 7606 (run-time) RP3-01 UL bandwidth overload alarm


Data/Voice

Issue: 01F DN09167685 35



3 Interworking

3.1 BSS10101 GSM-WCDMA Interworking

In order for an operator to provide seamless coverage in areas where WCDMA is not

available, such as rural areas, inter-system handovers are introduced. This feature

facilitates handovers between GSM BSS and WCDMA RAN. When the WCDMA and

GSM networks overlap, also an inter-system handover from GSM to WCDMA can be

made to release traffic load in the GSM system.

Flexi Multiradio BTS supports this feature as a GSM EDGE Base Station.

3.2 BSS11086 Support for Enhanced MeasurementReport

Support for Enhanced Measurement Report (EMR) provides the system with enhanced

serving and neighbor cell measurements. This is achieved by requesting the mobile

station (MS) to use the EMR for reporting downlink measurements.

Enhanced Measurement Report also provides the system with information such as

Downlink Frame Erasure Rate (DL FER), the usage of bit error probability (BEP) instead

of RX Quality during the DTX frames, and the support for reporting WCDMA RAN

neighbor cells. In addition, the EMR also provides an extended range for the serving and

neighbor cells downlink signal strength and the possibility to report altogether up to 15

GSM and/or WCDMA RAN neighbor cells in one report.

These reports can be used by the network to enhance the generic performance of the

existing system, enable GSM/WCDMA interworking, and enhance several features, such

as:

• Automated Planning

• FER Measurement

• Intelligent Underlay Overlay (IUO) and Intelligent Frequency Hopping (IFH)

Interaction with other features:

• The network does not order an MS to use the EMR for reporting when an Idle

Broadcast Control Channel (BCCH) Allocation List or a Measurement BCCH Allocation List is used in active state in the serving cell.

• With Common BCCH Control, when a call is in a non-BCCH frequency band, the

serving cell BCCH frequency is added to the BCCH frequency list.

• When the EMR is used for reporting, also the serving cell BSIC is added to the BSIC

list before sending it to an MS.

Benefits

• Improved generic performance of the system

• Enables GSM/EDGE/WCDMA interworking

• Improved performance of statistics

Interworking Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

36 DN09167685 Issue: 01F



3.3 BSS21520: RF Sharing GSM - LTE

The Flexi Multiradio BTS GSM/EDGE RF Modules can be used for GSM-only mode or

for concurrent use with WCDMA and/or LTE. If Radio Modules are shared, then SW of

Radio Modules can be managed by GSM or by the peer technology, WCDMA/LTE. The

software version of the shared Radio Module can be different from that of the System

Module SW version, when the software master is WCDMA or LTE.

From the BSC point of view, Flexi Multiradio LTE support is visible when some or all RF

Modules of Flexi Multiradio GSM/EDGE are configured as shared and some shared

modules have LTE as SW master. The BSC receives SW master information in Abis

O&M interface in ‘BTS type’ information element. Flexi Multiradio BTS usage is

controlled with TRX capacity license.

Requirements

• BSC S15 EP1.2

• Flexi Multiradio BTS EX4.1 or Flexi Multiradio 10 BTS GF1 1.0.0

Software Requirements

Table 6 Software requirements

Network element

Software release

LTE RL20 onwards

GSM/EDGE EX4.1 onwards or Flexi Multiradio 10

BTS GF1 1.0.0

NetAct OSS5.3 CD Set3 onwards

Hardware Requirements

Table 7 Hardware requirements

Network element

Required hardware

BTS Flexi 3-sector RF Module 850 70 W (FXCA)

or, Flexi 3-sector RF Module 900 70 W (FXDA)

or, Flexi 3-sector RF Module 900 90 W (FXDB)

or, Flexi 3-sector RF Module 1800 70 W (FXEA)

or, Flexi 3-sector RF Module 1800 90 W (FXEB)

or, Flexi RF Module 1900 Tripe 70 W (FXFA)

or, FHDA 900 band 2x40 W

or, FHDB 900 band 2x60 W


Interworking

Issue: 01F DN09167685 37



Table 7 Hardware requirements (Cont.)

Network element

Required hardware

or, FHEA 1800 band 2x40 W

or, FHEB 1800 band 2x60 W

and, Flexi BTS Multimode System Module

(FSMC/D/E for LTE and ESMB/C for GSM)

g GSM-LTE software support for each hardware depends on the market requirement.

3.4 Collecting logs using Snapshot feature

The 2G Flexi BTS Site Manager can be used for collecting the logs using File -> Save

As -> Save Snapshot option. It is recommended to collect logs using this feature

everytime while troubleshooting the site or when a problem ticket is created.

g Snapshot is meant to help Nokia R&D to analyze and resolve the tickets. It cannot be

opened or analysed in the field nor browsed with an off-line 2G Flexi BTS Site Manager.

g Not all internal logs are always available, so those will be skipped when the Snapshot is

being fetched. For example, when the BTS is uncommissioned state, SCF and

commissioning report will not be available.

The following logs can be collected using Snapshot feature:

1. Site Information Report - Collect logs for complete site information.

2. UKPT Logs - Collect internal logs for system module.

3. Baseband memory dump - Collect baseband internal logs.

4. Hardware Unit Logs - Collect RF Module/RRH internal logs.

Interworking Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

38 DN09167685 Issue: 01F



Figure 7 Collecting logs using Snapshot feature


Interworking

Issue: 01F DN09167685 39



4 Operability

4.1 2G Flexi BTS Manager Compatibility Launcher

The Compatibility Launcher communicates with the BTS and with the installed 2G Flexi

BTS Site Managers. It requests for parameters such as BTS SW version, Management

interface version, and BTS type from the BTS and also fetches the SW version and

Management interface version from the installed 2G Flexi BTS Site Managers. Based on

the values of these parameters, the Compatibility Launcher launches the appropriate 2G

Flexi BTS Site Manager.

The following functionalities are supported in the Compatibility Launcher:

• Local connection with BTS

• Remote connection with BTS

• Create SCF file in offline mode for commissioning

• Display help for Flexi Multiradio 10 BTS

• Uninstall other versions of 2G Flexi BTS Site Manager

The following screenshot shows the Compatibility Launcher:

Figure 8 Compatibility launcher-local connection

The following screenshot shows the Compatibility Launcher when it is trying to connect

to the BTS.

Operability Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

40 DN09167685 Issue: 01F



Figure 9 Compatibility launcher-connecting

In the Create File option, the user can select the desired 2G Flexi BTS Site Manager

version to create the SCF file in offline mode.

Figure 10 Compatibility launcher-Create File option


Operability

Issue: 01F DN09167685 41



Already installed versions of 2G Flexi BTS Site Manager can be deleted using the About

option:

Figure 11 Uninstall versions of 2G Flexi BTS Site Manager

4.2 BTS Trace Tool

BTS Trace Tool is built in the 2G Flexi BTS Site Manager application and can be used to

collect detailed logs when investigating a problem seen on a customer BTS site. The tool

can be controlled either via local or remote 2G Flexi BTS Site Manager minimizing the

need for site visits. The tool provides the functionality to collect logs remotely from the

BTS site over the Abis link. In addition to a few standard logs, custom logs can be

recorded as well with the help of custom trace set files provided by the Nokia customer

support team. The recorded log files can be decoded and analyzed by Nokia.

4.3 Antenna VSWR measurement

Flexi Multiradio BTS provides antenna line supervision by means of voltage standing

wave ratio (VSWR) monitoring. VSWR monitoring is implemented in Main (TX/RX)

antenna ports in Flexi Multiradio RF Module (FXxx) and Remote Radio Head module

(FHxx).

During commissioning, the user can set the VSWR minor (7607) and major (7606) alarm

limits for each Main (Tx/RX) antenna line (or branch) separately. The minor and major

limit can be set between 1.5 to 3.5 (in steps of 0.1). The default limits on the 2G Flexi

BTS Site Manager are 1.9 (minor) and 2.6 (major), that is 10 dB (minor) and 7 dB (major)

Return Loss respectively.


42 DN09167685 Issue: 01F



Figure 12 Setting VSWR limits using 2G Flexi BTS Site Manager

At the end of the commissioning process, the values are stored in the site configuration

file (SCF) in the System Module's (ESMB/C) non-volatile memory. The System Module

then gives these values to commissioned RF modules or RRH. During normal BTS

operation, RFM/ RRH modules continuously monitor Forward and Reverse TX power on

their Main (Tx/Rx) antenna ports. The RFM/RRH then calculate the corresponding

VSWR values every few seconds and compare them against the commissioned minor and major limits.

Normal mode

In normal mode, VSWR (return loss) can be monitored reliably if the forward TX power

on the antenna port exceeds approximately +22.5 dBm in RRH (FHxx) and +21 dBm in

RF Module (FXxx). This forward TX power is dependent on per TRX power (carrier

power in SCF plan), attenuation level defined for the all carriers allocated to MCPA

(PMAX, PMIN).

If the calculated VSWR value exceeds either minor or major limit, RFM / RRH led turns

red indicating a failure. If the failure continues or if no valid and good VSWR values are

reported on the affected branch, the alarms 7607 TRX OPERATION DEGRADED or

7606 TRX FAULTY are reported after approximately 3 minutes. With 7607 alarm, theaffected TRXs remain in operational state and the alarm is automatically canceled if the

VSWR condition improves. With 7606 alarm, all affected TRXs are blocked and manual

recovery is needed. Typical causes for a bad VSWR are broken cables, broken

connectors and the ingress of water in the antenna cable path.

Power tolerant mode

VSWR monitoring can also be set to a "power tolerant" mode which can be used if the

RF isolation between the antenna ports is continuously poor, for example, due to

external combiner characteristics. Both minor and major VSWR alarms remain

operational but higher Forward (and Reverse, respectively) power levels are needed to

trigger any alarms. This mode can be activated by setting both minor and major limits to

3.5 (max value) during commissioning. In this mode, the following applies:


Operability

Issue: 01F DN09167685 43



• RFM / RRH internally use the default values 1.9 and 2.6 for minor and major alarms

respectively.

• VSWR alarms are only reported if alarming VSWR condition is present and the

continuous TX Forward power has exceeded +37.8 dBm (RFM) / +36.0 dBm (RRH)for over 3 minutes.

g Like other BTS parameters, the VSWR minor and major values should be selected

according to the physical BTS environment to ensure that BTS detects real VSWR

problems but also does not raise unnecessary alarms. For example, the VSWR

condition may be constantly poor if there are any causes for increased reverse power,

like two Main antenna ports being connected in an external combiner with poor isolation

causing RF leakage (reverse power) between the ports. The VSWR condition can also

be expected to fluctuate if the antenna element vibrates during heavy wind periods.

g The expected VSWR / Return Loss measurement tolerance in the RFM and RRH HW

circuitry is ±2.6 dB. So for example, when default VSWR minor limit 1.9 is used(=Return Loss 10 dB) the minor VSWR alarm (7607) is triggered if the real Return Loss

condition is between 7.4 to 12.6 dB.

4.3.1 Antenna boosting on TCH-only TRX antenna lines

If a RF module branch contains TCH-only TRXs, then RF module reports “Invalid VSWR”

after 1 hour if there were no valid VSWR measurements during that period. This triggers

so-called antenna boosting where BTS O&M SW activates one of the TCH TRXs on that

branch for 3 minutes. If “Valid VSWR” value is reported before the timer expiry, the

scenario is abandoned. If the RFM still reports "invalid VSWR" after timer expiry, a

VSWR alarm is raised for all TCH TRXs allocated in this pipe. If BTS (sector) lock /

unlock is given while the VSWR alarm is active, antenna boosting is also done to verify

the TCH-only antenna line condition after recovery.

4.4 BSC download of Abis mapping

Abis mapping automates the process of providing Abis allocations on the BTS. Instead of

using the information from the Site Configuration File (SCF), the BTS configures the

allocation of the Abis using the information received from the BSC. This configuration is

performed by the BTS, by using mapping algorithms to convert BSC data into BTS Abis

allocations. The mapping between the BSC data and the interfaces at the BTS relies on

reference signals that are collectively known as the Abis Termination information of theBTS. The Abis mapping information is provided to the BTS. The Abis Termination

information is provided to the BTS during commissioning via SCF from the 2G Flexi BTS

Site Manager. One reference signal per interface is supported at the BTS.

g A restriction with this feature is that it might be unable to take into account the possible

cross-connections in the Abis line. The BTS believes the Abis timeslot allocations as

defined on BSC but they may not be the same anymore on the BTS end due to cross-

connections (if TS offset is also used).

An Abis mapping Information Element (IE) consists of Abis channels (TRXSIG and TCH)

in BTS_CONF_DATA grouped into a bundle. The BTS_CONF_DATA can carry several

instances of Abis mapping IE(s), one for each bundle or interface. The interface time


44 DN09167685 Issue: 01F



slots in the Abis mapping IE(s) from the BSC are the time slots at the BSC interface.

OMUSIG configuration is still taken from the Abis Termination information already stored

at the BTS, and not from the Abis mapping IE. The timeslot information provided in the

Abis mapping IE is converted into timeslot information for the BTS via the Abis mapping

algorithm. EDAP information is provided using the Dynamic Pool Info IE(s) in the

BTS_CONF_DATA. The interface time slots in the Dynamic Pool Info IE(s) are the time

slots at the BSC interface. At the BTS, one bundle per interface is supported, and, at the

BSC, multiple bundles per interface are supported. However, one bundle cannot include

multiple interfaces.

The 2G Flexi BTS Site Manager supports Abis mapping download function:

• The Transmission menu of the 2G Flexi BTS Site Manager has the BSC Abis

Mapping Status view menu item. This is enabled when the BSC Abis Mapping

feature is in use, and disabled when the feature is not in use.

– The BSC Abis mapping facilitates the user to view the differences and conflicts in

the BSC and BTS allocations for a selected interface or a BSC bundle. The user can select an interface from the list of interfaces displayed in the Transmission

equipment view or select a BSC bundle from an available list of bundles. As per

user selection, the details of the BTS interface, reference signal and the

calculated offset value are displayed.

– This is only available in online mode for already commissioned BTS.

• Two check boxes have been added for the BSC Abis mapping download function in

the Abis Termination screen of the Commissioning Wizard:

– Enable Abis Signal Mapping allows the user to enable/disable the Abis signal

mapping.

–

Allow Abis Allocations from 2G Flexi BTS Site Manager allows the user toenable/disable the Abis allocations from the 2G Flexi BTS Site Manager. If this

check box is selected and the user enters the Abis allocations from the 2G Flexi

BTS Site Manager, they might later be overwritten by the allocation data from the

BSC.

– These options are available in both online and offline mode.

4.5 BSS20847 Automatic commissioning of the FlexiMultiradio BTS GSM/EDGE

Flexi Multiradio BTS GSM/EDGE is designed so that it is easy to install and commission.Easy commissioning needs support also from the BSC. The following functions are

related to the automatic commissioning of the Flexi Multiradio BTS GSM/EDGE:

• The BSC must be able to download Abis mapping to the BTS as Abis mapping

allows the BSC to dynamically provide the Abis allocations (TRXSIG, TCH, and

EDAP) for a BTS. The BTS configures the Abis allocations of the TRXSIGs, TCHs,

and EDAPs using the information received from the BSC, instead of getting the

information in the SCF. The mapping between the BSC data and the interfaces at the

BTS relies on reference signals (one per interface (E1/T1) at the BTS) which are

collectively known as the Abis termination information of the BTS. The Abis

termination information is provided to the BTS during commissioning via SCF from

the 2G Flexi BTS Site Manager.


Operability

Issue: 01F DN09167685 45



• When the site is commissioned, the BSC must automatically unlock the BCF when

the BTS informs that it is ready.

The 'Auto unlock allowed' is a configurable functionality (a BCF-level parameter in

the BSC).

4.6 BSS20817 End to End Downlink Abis PerformanceMonitor

BSS20065, in BSC S11.5 SW, implements counters in the BSC that check the uplink

signalling channels (channels using LAPD), keeps the results in a set of counters, and

every 24 hours checks the number of errors (CRC errors) against an alarm threshold.

BSS20817 is an equivalent feature for the Downlink Abis.

The BTS keeps downlink counters for each LAPD connection that terminates in the BTS.The counters measure the number of received bytes, the number of CRC errors and the

number of T200 timeouts. The BTS reports the counter numbers, per channel, every

hour between 10 minutes before the hour and the top of the hour according to the BTS

real-time clock.

4.7 BSS20063 Space Time Interference RejectionCombining

The Space Time Interference Rejection Combining (STIRC) is a licence-based

application software in the BSC that enables/disables the use of STIRC technology in the

BTS.

The STIRC is an uplink (UL) receiver performance enhancement to the Interference

Rejection Combining (IRC) technology. When enabled, the STIRC technology is

deployed in the UL by BTS. When disabled, the current IRC technology is deployed by

the BTS.

The new technology improves the spectral efficiency of the network via link performance

enhancement that significantly improves the interference (co-channel and adjacent

channel) rejection capability of Flexi Multiradio BTS in the uplink direction. For example,

the improved link level interference rejection performance of the STIRC with GMSK

modulation will give on average a gain of 4 to 9 dB for co-channel interference compared

to the IRC in 2-way Uplink Diversity (2UD) configurations. In addition, the current GMSK

normal burst receiver sensitivity levels are not affected.

The STIRC can also help to maintain the link balance (UL and DL) needed with the

deployment of Single Antenna Interference Cancellation (SAIC) technology in mobiles

that improves interference cancellation capabilities in the downlink (DL).

The STIRC licensing software will be operational once the STIRC option is enabled at

the BSC. The BSC will allocate the STIRC license from its available pool and send the

STIRC option in the BTS_CONF_DATA to the BTS.

This feature affects alarm handling so that STIRC alarms can be cancelled without reset.


46 DN09167685 Issue: 01F



Implementation

The STIRC feature can be enabled or disabled for the site any time the BTS is running

because it does not require locking the sector or TRX. The BSC will send the STIRC

option for each sector in the BTS_CONF_DATA. When receiving this option, the BTSO&M SW checks for each TRX in the sector for which STIRC is enabled, whether the

HW configuration is valid for the STIRC feature. If an invalid configuration is used, an

alarm is raised on the specific TRX(s) and these specific TRX(s) are blocked, and STIRC

is enabled on rest of the TRX(s). BTS O&M SW enables the STIRC algorithm by

informing the DSP of each valid TRX in the sector.

Note that the STIRC algorithm implementation requires 32-bit precision numerical

calculations to minimize quantization errors, while for the IRC algorithm 16-bit precision

is sufficient. Thus, for STIRC implementation 32-bit precision is used for all the functions,

some of which are common to the IRC algorithm also. As a result of this, slight gain (up

to 0.2 dB) in CCI and ACI performance can be observed even when the IRC algorithm is

used (STIRC=N).

In order to achieve the STIRC gain, Rx Diversity should be in use (RDIV=Y).

Requirements

This feature is supported by the following BTS generations and SW:

• Flexi EDGE EP2

• UltraSite CX5 with EDGE TRXs (BB2E/BB2F and TSxB) and Hybrid TRX

(BB2E/BB2F and TSxA).

• MetroSite CXM5 with EDGE TRXs

• BSC S12

• EX3.1 Flexi Multiradio• Flexi Multiradio 10 BTS GF1.0


• All valid hopping combinations for the supported TRX types are supported.

• BSS synchronisation helps in achieving full STIRC gain.

Benefits

The STIRC diversity algorithm improves the interference rejection performance and thus

the overall network spectral efficiency and quality.

The STIRC ensures better uplink quality, particularly in high user density/interferencelimited scenarios, and better average user data throughput, as well as improved traffic

and control channel performance. It also provides a possibility to use less mobile Tx

power for quality-based uplink power control, which leads to reduction in the overall

interference level in uplink and improves the mobile battery life.

4.8 BSS20040 User Access Level Control (UALC)

The User Access Level Control (UALC) is a solution to prevent unauthorized users from

making changes that can affect the remote management and traffic. The UALC is for a

remote connection only, in a local connection it is not in use.


Operability

Issue: 01F DN09167685 47



The UALC defines two levels of access rights for the users of 2G Flexi BTS Site

Manager:

• Full Access (Read and Write) means that all the functions that the manager

applications offer are available to the user.• Limited Access (Read only) allows only to read information from an element.

Assignment of user rights is via the existing Windows user management processes. The

2G Flexi BTS Site Manager applications can start-up and operate independently

regardless of the Windows User Administration.

The 2G Flexi BTS Site Manager applications check if the User Access Level Control is

enabled or disabled by reading the registry key 'Access Levels' under

KEY_LOCAL_MACHINE/Software/Nokia/2G Flexi BTS Site Manager:

• 'ON' – UALC is enabled.

• 'OFF' – UALC is disabled.

If the UALC is disabled, the application gives Full Access Rights (both Read and Write)

to the user. If the registry key is not present, by default Full Access Rights are granted.

In case the UALC is 'ON', that is, enabled, the EM application checks if the user currently

logged in belongs to the Nokia BTS_Administrator group or not. If yes, the user is given

Full Access Rights (both Read and Write). Otherwise, Limited Access Rights (Read only)

are granted. If the Nokia BTS_Administrator group is not present on the PC/domain, by

default Limited Access Rights are granted.

In case 2G Flexi BTS Site Manager is installed and the BTS_Administrator group does

not exist on the PC, the user can create the group either using a SiteWizard installer or

manually.

Creating the Nokia BTS_Admins user group manually

To create the Nokia BTS_Admins user group manually, follow the instructions below. Add

the PC's login ID to the Nokia BTS_Admins group using the Control panel.

1. Go to Control Panel > User Accounts.

2. Click on the Advanced tab and then the Advanced button. A new window Local

users and groups is displayed.

3. Select a group and then create a new group 'Nokia BTS_Admins' by right-clicking on

RHS.

4. Select the newly created group, right-click the Add to group option, and then click

Add. The Select Users, Computers, or Groups window is displayed.5. Enter your PC login ID to the 'Enter the object names to select' and click OK.

Creating the User Access Level Key manually

To create the Access Levels key manually, follow the instructions below.

Registry location: KEY_LOCAL_MACHINE/Software/Nokia/2G Flexi BTS Site Manager

Access Level Key name: Access Levels

Value: ON

1. Open the Command Window, type regedit, and press Enter to open the 'Registry

Editor'.


48 DN09167685 Issue: 01F



2. Go to HKEY_LOCAL_MACHINE/Software.

3. Create a 'Nokia' Key by right-clicking on Software > New > Key, if not present.

4. Create a '2G Flexi BTS Site Manager' Key by right-clicking on Nokia > New > Key, if

not present.5. Create 'Access Levels' string values by right-clicking on 2G Flexi BTS Site Manager

> New > String Values.

6. Modify the value of 'Access Levels' by right-clicking on Access Levels > Modify. Type

ON in the value data and press Ok.

4.9 BSS11047 Intelligent shutdown for Flexi MultiradioBTS GSM/EDGE

To provide protection against a mains power break, the operator can equip a BTS with a

battery backup system. The “Intelligent shutdown” feature is controlled by the BSC andits purpose is to maintain the BTS site operation for as long as possible by reducing

capacity so that only the essential site functions are maintained.

When a mains breakdown takes place, then BTS sends an alarm to the BSC, which

performs forced handovers for all the calls on the TRXs to be shut down. The calls are

handed over to a TRX, which will remain powered, or to adjacent cells and finally the

BSC orders the BTS site to stop transmission for the TRXs involved. When the main

power is restored the BSC takes the BTS automatically back in full service.

On a BTS site basis, the user can define the service level of the site to be maintained

while the battery backup is in use. Also, two timers can be defined, allowing the

execution of the shutdown procedure in phases, reducing capacity in a controlled way.

Three service level options are available:

• Full service – Service is maintained at full capacity for as long as the battery power

supply lasts. The two timers are ignored.

• Broadcast control channel (BCCH) backup – The BTS maintains full capacity until

the first timer expires. After that, all active calls on non-BCCH transceivers are

handed off. The non-BCCH transceivers are blocked from carrying any new calls and

the BSC commands the BTS to shut them down. The BCCH TRX(s) are maintained

to offer minimum service.

• Transmission backup – The second timer starts after the first one has expired. After

the expiry of the second timer, all active calls on BCCH transceivers are handed

over. The BCCH transceivers are blocked from carrying new calls and the BSC

commands the BTS to shut them down. Only the BTS transmission equipment power is maintained to secure the functionality of a transmission chain for as long as the

batteries last.

When the mains power is restored, the BSC commands the BTS site to power all the

shut down equipment and return back to full service.

Battery backup configurations for Flexi Multiradio BTS GSM/EDGE:

• Flexi with Multi Integrated Battery Backup Unit (MIBBU)

• Flexi with Integrated Battery Backup Units

• 3rd Party Battery Backup Solution


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Issue: 01F DN09167685 49



The optional battery backup system for the Flexi Multiradio BTS GSM/EDGE is selected

in the 2G Flexi BTS Site Manager during the commissioning phase.

If 3rd party BBU solution is used, one external alarm (EAC) line needs to be designated

to indicate a mains power loss/restoration from the BBU. The selected EAC line needs tobe configured as a Mains alarm at the BSC. If Nokia BBU solution (FPxA, MIBBU or

FPRx) is used, the FPA connector on the ESMB/C System Module can be used with no

need to use nor configure any EAC lines. Note that if an EAC line is configured as a

Mains alarm at the BSC, the BTS ignores the FPA connector.

With all BBU solution options, the BTS generates alarm 7995 Mains Breakdown when

the BBU indicates mains power loss. The 7995 alarm then triggers the Intelligent

Shutdown procedure at the BSC. If two or three phase supply is used with MIBBU or

FPRx, the loss of one phase already generates the 7995 alarm.

In addition to alarm 7995, the FPA interface can also generate three other BBU-related

alarms 7612/7613/7614 (note that with FPMA, only 7995 and 7613 alarms can be seen).

Benefits

The operation is optimal during both short and long mains breaks. Timers allow

executing the shutdown procedure in several phases. Each phase reduces the battery

power consumption.

With intelligent shutdown, the operator can define the service level to be applied on a

mains failure to optimize the trade-off between the service level and battery power

lifetime. A short mains break will not reduce the service unnecessarily, whereas during a

longer break, the essential functions, such as BCCH or transmission chain, are

maintained for as long as possible.

4.10 Remote mode of 2G Flexi BTS Site Manager

The user can control Flexi Multiradio BTS equipment locally via 2G Flexi BTS Site

Manager. To minimize the need for site visits, 2G Flexi BTS Site Manager functions can

also be accessed remotely.

The user can monitor and test the BTS remotely, by connecting the 2G Flexi BTS Site

Manager to the BTS remotely via NetAct™. A PC with the 2G Flexi BTS Site Manager

software is used as a user terminal.


50 DN09167685 Issue: 01F



Figure 13 2G Flexi BTS Site Manager connected in remote mode

The user can connect to a remote BTS using the 2G Flexi BTS Site Manager application,

via a menu item and/or a toolbar button, or via the command line. The user interface of

2G Flexi BTS Site Manager informs the user of the remote connection status when

information is being requested from the remote BTS, and when the 2G Flexi BTS Site

Manager is processing received information from a remote BTS. 2G Flexi BTS Site

Manager connected in remote mode supports all features available via a local

connection, except the Control Abis interface (enable/disable) commands.

It is not possible to perform the initial BTS commissioning remotely, but it is possible toperform subsequent recommissioning or append commissioning from the 2G Flexi BTS

Site Manager in remote mode.

At the BTS, the messages sent from or to the 2G Flexi BTS Site Manager in remote

mode are re-routed, but handled in the same way as with the local connection.

The alarm 7801 MMI CONNECTED TO BASE STATION indicates whether the 2G Flexi

BTS Site Manager is connected to the BTS locally (alarm text Local MMI connected)

or remotely from NetAct (alarm text Remote MMI connected).

4.11 BSS10063 Rx Antenna Supervision by ComparingRSSI

The purpose of Rx Antenna Supervision by Comparing received signal strength indicator

(RSSI) is to monitor the Rx antenna condition. Rx antennas can be monitored for major

problems by taking a long-term average of the difference between the Main Rx RSSI and

the Div Rx RSSI. This feature provides continuous antenna supervision for the BTSs,

which have the Main Rx RSSI and the diversity in use. It also offers an alternative

solution for Tx monitoring in cells that use duplexing. This detects, for example, antennas

with poor voltage standing wave ratio (VSWR) and inadequate feeders.


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Issue: 01F DN09167685 51



The monitoring is based on the principle that all received bursts where the Rx level of

main or diversity branch is above the defined limit value (-100 dBm) are accepted as

samples and used in the averaging process. A minimum of 160000 samples in one hour

must be collected for the BTS to assume that the results are reliable and therefore could

be used to raise an alarm.

The differences of the TRXs connected to the same antennas are counted up, and the

average difference for main and diversity antennas is calculated. If the difference is

above the threshold (default value 10 dB), and the number of samples indicate that the

results should be reliable, an alarm is activated. The threshold default value of 10 dB can

be changed by a parameter at the BSC between 3 and 64. The functionality of the

feature can be disabled.

It is still possible that both antennas are damaged simultaneously and the samples from

both antennas remain below -100 dBm limit value. Therefore, the difference algorithm

cannot detect the fault. For this reason, the BSC also observes the assignment and

handover success rate.

Note that the RSSI values observed from 2G Flexi BTS Site Manager may not be the

same on both of the carriers of a RF Module. The difference between carriers can be

greater than 10 dB, depending on the Rx level of the calls made on both carriers. If the

average uplink Rx level of calls (CS/PS) made on Carrier 1 is high compared to Carrier

2, this difference can be seen and this is not a problem. It implies that calls on Carrier 1

are being made from mobiles that are near to the BTS, while calls on Carrier 2 are being

made from mobiles that are relatively far from the BTS. The RSSI difference between

two carriers is different from the case where an RSSI alarm is raised. The alarm is raised

because of the difference in the Rx level of the main and diversity paths of a carrier.

However, this alarm is not valid for the comparison done across carriers. Moreover, the

comparison of RSSI values across carriers is not valid in Nokia UltraSite EDGE BTS, as

a TRX in the UltraSite EDGE BTS supports one carrier only, whereas in the FlexiMultiradio BTS, the RF Module supports two carriers.

Benefits

Rx Antenna Supervision by Comparing RSSI can identify antenna problems without the

need for active tests.

Collection and display of raw RSSI measurements

In addition to the newest and last reliable received signal strength indicator (RSSI)

values, the BTS also gathers the raw RSSI results periodically from the TRXs. These

results are displayed in the 2G Flexi BTS Site Manager.

Settable RSSI sample limit

The number of received signal strength indicator (RSSI) samples, needed for a valid

RSSI calculation, can be configured using the Element Manager according to the traffic

density. The RSSI sample can be configured to values: 80000, 160000 (default), 350000

and 750000. The value 80000 is preferred when the BTS is located in a rural area and

when the traffic density is low. The values 350000 or 750000 are preferred when the

BTS is located in an urban area and has high capacity utilization. In areas with

intermediate traffic density it is preferred to use the default value 160000.

The RSSI sample value may also be configured during the commissioning phase.


52 DN09167685 Issue: 01F



Alarm Start and Cancel

The BTS estimates the number of samples it would receive for high/medium traffic

profiles by setting an internal threshold value, which is a multiple of the user defined

RSSI sample count. This value is an internal value and is not visible to the user.

The RSSI alarm is raised when:

• In the first hour, the received sample count is greater than the internal threshold and

the RSSI alarm conditions are valid.

• In the first hour the received sample count is greater than the user configured RSSI

sample threshold, but less than the internal RSSI alarm threshold. Then, the BTS

software waits for the next hour to determine whether the RSSI alarm is to be raised.

• In the consecutive second hour the received sample count is greater than the

internal RSSI alarm threshold or the user configured RSSI sample threshold and the

RSSI alarm conditions are valid. If the user configurable sample count is changed

during this hour then the monitoring is reset and the process restarts from the firsthour.

The alarm is cancelled automatically in the next hour if the sample count is greater than

the user configured sample count and the alarm condition has been cleared.

4.12 BSS9068 BTS SW management

The BTS software package consists of a master file and several application files. You

can update the BTS software by downloading the new BTS software remotely from the

BSC. A site visit is not needed.

You can download the BTS software to a BCF in the background during normal

operation, without impact to ongoing traffic or any other operation of the base station.

Software downloading is also automatically triggered after BCF reset if the System

Module does not have the correct BTS software package stored locally (that is, the

package set as default for that particular BCF at the BSC).

When the BTS software is downloaded from the BSC, the process is optimized by

downloading only those application files which have been updated. Application files that

are unchanged from those already stored locally in the current BTS software package

are not downloaded. This minimizes the download time for a new BTS software package.

RF Module and RRH software is included in the BTS SW package and is automatically

upgraded or downgraded whenever the BTS SW package is upgraded or downgraded.

You can also download the BTS software with 2G Flexi BTS Site Manager to minimize

BTS boot-up time for new installations. In this case you do not need to download the

BTS software package from the BSC after BCF reset.

The downloaded BTS software package is stored in the flash memory of the System

Module (ESMB/C). The flash memory of the System Module contains two complete BTS

software packages to ensure recovery in the event of a download or start-up failure.


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4.13 BSS9058 BTS fault recovery

BTS fault recovery minimizes the effect of service level faults within the BTS. All objects

and interfaces are continuously monitored, and appropriate recovery actions are taken

when needed. Alarms are raised to indicate faults, which leads to recovery actions being

taken.

For more information on fault recovery and BTS alarms, see Trouble Management of

Flexi Multiradio BTS GSM/EDGE.

4.14 BSS9063 Abis loop test

The purpose of the Abis loop test is to verify the Abis transmission set-up and quality.During the Abis loop test, Flexi Multiradio BTS generates a test signal pattern in Abis

uplink for the timeslots under test. The BSC group switch loops the selected timeslots

back to Abis downlink where the BTS checks the integrity of the received signal. The

Abis loop test can be run on the TCH and Dynamic Abis Pool timeslots. After the test,

the BTS provides the related test reports to the BSC. The Abis loop test is run

automatically during BTS commissioning. The test can also be run manually from the

BSC.

Up to 12 simultaneous Abis loop tests can be tested if no Abis protection loops are used.

If they are used, then up to 6 Abis loop tests can be run simultaneously. This feature is

not supported with Packet Abis.

4.15 BSS9062 BTS supervision

The Flexi Multiradio BTS Base Station monitors and tests itself during operation without

a separate command.

Continuous monitoring

Both the software and hardware carry out monitoring. Most of the monitoring procedures

are so effective that no additional testing to find the faulty module is needed. The

following items are monitored continuously:

• Internal buses of the base station• Transmission equipment and interfaces

• RF parts

• Mast head amplifiers

• Flexi Support and Flexi Multiradio BTS Base Station Battery Backup (MIBBU)

• Temperature (heating and cooling) system of the base station

• Power supply voltages

• Reference Oven Oscillator


54 DN09167685 Issue: 01F



AC mains breakdown

A typical short voltage drop (that lasts less than 20 ms) in the AC mains supply does not

cause any detectable harm to the operation and does not cause an alarm. In case of a

mains breakdown, the Flexi Multiradio BTS Base Station cannot send an alarm to theBSC without battery backup (either integrated or external).

4.16 BSS9061 Temperature control system

Flexi Multiradio BTS Base Station monitors its temperature continuously with several

sensors located in the System Module (ESMB/C) and RF Module (FXxx).

The BTS controls its temperature with cooling fans to provide as stable operational

conditions as possible. Heating and cooling is controlled gradually depending on the

ambient temperature to ensure low temperature gradients and noise level.

During BTS start up, System module and Radio Modules can be powered on from the

ambient temperature of –35˚C (-40˚C, in case of 2x60 W RRH). When ambient

temperature is outside normal range (< -5˚C), additional startup time is added by linearly

extrapolating startup time value between following data points:

• -5°C: 2 minutes



The 2x60 W RRH starts 10 minute timer till the core temperature of the RRH reaches

above -40 ˚C. This additional time is needed for RFM heating. It is assumed System

Module heating will happen within this time.

During commissioning, a climate control profile can be selected from three options

depending on the BTS site environment:

• LOW NOISE minimizes fan noise for low and moderate ambient temperatures.

• OPTIMISED COOLING (default profile) maximizes unit reliability by running fans with

maximum speed already in moderate ambient temperatures.

• LINEAR RESPONSE is an intermediate profile which increases fan speed linearly as

the temperature increases.

If the temperature of a module rises too high, a temperature alarm is issued. If the

System Module is overheated, the BCF is blocked. If the RF Module is overheated, the

associated TRXs are blocked. Power supply units have their own internal shutdown andrecovery in case they are overheated.

All Flexi Multiradio BTS modules operate over full operational temperature range without

the need for external heaters.

4.17 BSS9060 TRX Test

The total performance of the TRX is tested with a multi-purpose TRX Test. The test time

is approximately 15 seconds and it covers the following:

• Digital and RF parts

• Rx operation and Tx level


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Issue: 01F DN09167685 55



• Both Rx branches

When the TRX test is carried out according to a regular schedule, it can be used in TRX

performance supervision.

Both Rx branches (Main and Diversity) are tested separately during the same TRX test.

Diversity is tested if "Rx" port (Ant2, Ant4, Ant6) is configured in use and if Diversity is

enabled on BSC. Otherwise, only the main branch is tested. Only the main branch is also

tested if Rx Diversity is coming from another branch, for example, in antenna optimized

configurations.

The TRX Test tests both the Tx and Rx RF paths of the selected TRX via an up looped

burst to the Air interface, including the RF Module (FXxx). The looped back signal is fed

back to the Rx path where the BER, Rx Level, and Rx Result are measured. The

reported Tx power is derived from the received RX level.

The Tx power level used during the TRX test is the same as the power level of the

broadcast control channel (BCCH). To avoid unwanted disturbances to the TRXs, thetraining sequence is not the same as the one normally used.

Figure 14 TRX Test window

All TRXs in the BTS can be tested either remotely from the BSC or the NetAct or

locally/remotely with 2G Flexi BTS Site Manager. If the TRX test which is run from

NetAct or the BSC fails, the test must be rerun remotely or locally with 2G Flexi BTS Site

Manager. The detailed failure reasons can be obtained from the 2G Flexi BTS Site

Manager and from BSC if the feature "RG301831 Enhancement on TRX Test" is

activated. Troubleshooting instructions for these failure reasons can be found in the

document, Trouble Management of Flexi Multiradio BTS GSM/EDGE .

It is possible to run the TRX Test after the TRX object is blocked from the 2G Flexi BTS

Site Manager. It is also possible to run the TRX Test after the TRX object is locked from

the BSC. Note that the TRX test can be performed only in traffic channel (TCH)

timeslots. Two free timeslots are needed for the test.


56 DN09167685 Issue: 01F



The TRX test is not possible when baseband or antenna hopping is used. The TRX Test

cannot be commanded for a TRX configured to cover the extended/super extended outer

area.

4.18 TRX Loop Test

Flexi Multiradio BTS provides a TRX Loop Test facility. In a TRX loop test, data

generated by SW in digital parts of the TRX is looped from the TX to RX side inside the

RF Module (FXxx), so that the TX and RX chains excluding antennas and antenna

feeder cables are tested. Main or diversity paths can be tested.

The BTS checks the looped test data, and the test result is given as BER values. The

TRX Loop Test can be performed with GMSK TCH/FS or 8PSK PDTCH/MCS-5 test

channels.

Two different Loop Back points can be selected on the BTS Manager: DSP-ABIS1-AIR3or AIRTESTER-ABIS1. Loop back points are used to turn downlink traffic back to uplink.

In addition, also the Modulation (GMSK or 8-PSK) and Channel Type (TCF or TCH with

various sub-options) can be selected.Typically, AIRTESTER-ABIS1 loop is used to

measure the BTS RX (Uplink) performance with an external test equipment.

4.19 BSS9059 Nokia BTS resets

You can separately trigger a reset of BCF, BTS, or TRX objects. An object reset can be

triggered from the BSC, NetAct, and from 2G Flexi BTS Site Manager. In addition, the

2G Flexi BTS Site Manager can also command HW resets for the System Module(ESMB/C) and RF Module (FXxx).

Object resets

• BCF (site) reset: resets all modules/units in the site except transmission sub-modules

(FIxx), which ensures that active cross-connections are not interrupted.

• BTS (sector) reset: resets a single BTS object, including all TRXs that are part of the

BTS object configuration. It has no impact on other BTS objects which are part of the

site.

• TRX reset: resets a single TRX. Only the targeted TRX object is impacted.

g

OMU reset is not supported.

Module resets

Module resets are provided as a recovery mechanism for exceptional conditions. In

normal operation, there should be no need to invoke this type of reset.

• System Module reset: reinitializes all hardware and software in the System Module.

This is equivalent to a power on reset. Transmission is also re-initialized, and there

will be a brief interruption in the cross-connect traffic.


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4.20 BTS Auto-detection

4.20.1 BSS9056 Auto-detection of Site Configuration

Flexi Multiradio BTS Base Station detects the site configuration automatically, including

all active modules, their hardware versions, and product codes. This information is

stored in the non volatile memory of the System Module (ESMB/C), and it can be

displayed in 2G Flexi BTS Site Manager.

The user needs to set the operator-specific settings, such as external alarm line settings,

from the BSC or the NetAct, for example with the SCF.

The following Baseband Bus properties are detected:

• State - disconnected/established

• Technologies that the hardware is shared with

• Whether the configuration carries only payload, or FCB and Ethernet also

• Distance between the System Module and RF Module

In addition to the attributes mentioned above, the timing, routing, capacity allocation

rules, and register views can also be viewed.

A possible change in any of the modules or in the configuration causes an automatic site

configuration update in the flash memory of the System Module. The configuration is

detected both in normal start-up situations and when extra capacity (more TRXs) is

added, modules are removed, or a faulty module is replaced with a new one. The

transmission configuration is part of the site configuration file (SCF), which is stored in

the System Module (ESMB/C).

With this feature, AISG compliant antenna line devices (such as Mast Head Amplifier)

can also be auto-detected.

4.21 48 V DC input voltage supervision

The System Module (ESMB/C) supervises the 48 VDC input voltage continuously. When

the input voltage decreases below 40.0 V DC or increases above 58.0 V DC, BCF

notification alarm 7602 Supply voltage to ESMB/C near low/high limit is activated to

indicate that the input voltage is close to exceeding its normal operating range.

Once the input voltage is back in the permissible range of above 40.0 V DC to 58.0 V

DC, the 7602 notification alarm is cancelled.


58 DN09167685 Issue: 01F



4.22 BSS20958 Energy saving mode for BCCH TRX

The “Energy saving mode for BCCH TRX” (BSS20958) feature introduces a configurable

power saving mode for the BCCH TRX. It aims to achieve lower electricity consumption

by reducing the transmit power of the BCCH TRX. This feature reduces the transmit

power level of dummy bursts on idle circuit-switched channels of the BCCH carrier by 2

dB. The feature also enables 2 dB dynamic power control on active dedicated circuit-

switched channels of the BCCH TRX. This feature reuses, for the circuit-switched

channels of a BCCH TRX, the same exceptions that the 3GPP specifications allow for

the maximum output power of 8-PSK modulated channels.

The feature is controlled using a license key at the BSC level.The reduced electricity

consumption due to the “Energy saving mode for BCCH TRX” helps operators to reduce

network operating costs. With dynamic power control of active dedicated channels, the

feature reduces electricity consumption throughout the day and night. The reducedtransmit power of dummy bursts, and the limited dynamic power control allowed for

active CS channels, result in a reduction in downlink interference caused by the BCCH

frequency.

4.23 Resource Allocation Algorithm

4.23.1 Overview

The resource allocation algorithm runs in the BTS O&M software and allocates RF TRX

resources to logical objects specified in BTS_CONF_DATA. Depending on the factors

like conflicts with allocations of peer technologies, the RF Module decides whether the

allocated resources can be set up or not.

The following sources provide inputs for the algorithm:

• Sector configuration in the BSC - number of TRXs, number of sectors, used

ARFCNs, and RX diversity.

• Local Sector configuration in the SCF - this is defined during BTS commissioning.

Information about branches available in a local sector is derived from the antenna

groups.

• HW capability information of the auto-detected RF Modules

The output is a set of sub-sets of TRX objects (with their ARFNs/MA lists) that are to beallocated to antenna ports (or branches) in a local sector.

4.23.2 General resource allocation rules

The following are the general rules that are followed for the allocation of resources:

• The algorithm attempts to allocate all TRXs belonging to the same sector in one

branch but if they do not fit (due to frequency or power budget, or number of

carriers), it allocates them in other antenna ports associated for the same local

sector.

• Dedicated RF Modules are given preference over shared RF Modules


Operability

Issue: 01F DN09167685 59



• The selection of branches is started from the RF module that is connected to the

lowest numbered optical port on the system module, where OPT1 is the lowest and

OPT4/EXT is the highest.

•

Of all available branches in the selected RF Module belonging to the same localsector (in chain or otherwise), selection begins from the highest numbered branch to

the lowest numbered branch

• If multiple antennas of the same RF Module are assigned to same sector, the highest

numbered antenna is used first

• RF Hopping TRXs are preferred over non-IDD and non-hopping TRXs

• Priority of allocation is given in the order BCCH TRX, IDD TRX, TCH TRX

• The same antenna resources are shared by multiple GSM and WCDMA operators

• The number of GSM and WCDMA carriers supported in the Concurrent Mode site

remains the same. The carriers are distributed among multiple GSM and WCDMA

operators

• There can be the maximum of three GSM operators and two WCDMA operators in

the MOBSS RF sharing configuration

g TCH TRXs which have the nearest frequencies to BCCH are allocated to the same

branch if it is possible. The remaining TCH TRXs (if there are any left unallocated), are

allocated on the next branch or branches associated for that local sector.

g In case the frequency in both pipes exceeds 35MHz, the FHxB RRHs cannot

accommodate it. Reduce the frequency allocated span to max 34.8 MHz in downlink.

No limits in uplink, for example antenna optimized configurations are possible to be

made wider – with 2 different RRHs only.

g During the planning phase, limit to max 60 MHz UL frequencies bandwidth, and 35/40

MHz DL bandwidth window, covering all carriers irrespective of technology of both pipes

at the same time.

g In case UL BW limit is accidentally exceeded with antenna optimized configuration

comprising both pipes in the same sector/cell when observed from both pipes, the last

configuration request should be NACKed, that is followed by 7606 TRX object allocation

failed in RF module, rack=0x03 (indicates frequency budget violation).

4.23.3 RF allocation procedure

Resource allocation happens during configuration of the BTS and during reconfigurationwhen TRX objects have been added/removed, and if the SCF and hardware auto-

detection allows it. At reconfiguration resource allocation is done at the latter part of

configurtion after software is downloaded, module related configuration is done, sync is

provided, and before configuration is completed.

The RF allocation procedure is performed in the following steps:

1. Determine the maximum number of configurable TRXs per branch – The number of

configurable TRXs per pipe is up to six depending on the maximum power per

branch and per TRX power.


60 DN09167685 Issue: 01F



2. Divide the TRX objects into TRX lists (BCCH, IDD, and TCH TRXs) – The algorithm

divides the TRX objects into three TRX lists according to the TRX type and sorts

them in ascending order of the ARFN. Resource allocation is done as per the rules

specified in 2 General resource allocation rules.

3. Allocate TRX objects – The order of resource allocation is BCCH TRX, IDD TRX,

TCH TRX and always starts from the first branch in the order. In case of an IDD TRX,

IDD A is allocated to the next eligible branch to IDDM such that frequency budget is

not violated or no more branches are available.

After resource allocation, if auxiliary IDD TRX paths are allocated by append

commissioning, then it should be followed by a reset operation.

The algorithm for RF hopping follows the same procedure as followed by the algorithm

for non-hopping/BB sectors. The difference between the two is that when allocating a

TRX object to a branch, both the lower and higher cut-off frequencies in a TRX object’s

MA list are compared for fitting into the frequency budget of a branch. Therefore, it is a

good idea to determine the high and low cut-off frequencies when computing the centrefrequency.

Example 1: 4+4+4 configuration with one RF Module

In the following figure:

• Per TRX power = 15 W

• Maximum power per branch = 60 W

• Maximum number of configurable TRXs per branch = 4


Operability

Issue: 01F DN09167685 61



Figure 15 RF resource allocation

BCCH IDD TCH Unalloc-ated

Sector config

Obj Id ARFN

1

2

3

4

5

6

7

8

9

10

520

680

530

700

540

640

720

650

550

740

520

720

740

530

540

550

640

650

680

700

Threesorted lists Pipe N Pipe N-1 Pipe N-2

Finalallocation Alarms

520

720

740

530

540

550

640

650

680

700

520

520

740M 740 A

720M 720 A

740 A

720 A

740M

720M

550 650 700

540 640 680

530

520

After IDD TRX allocation

After TCH TRX allocation

Per TRX power = 15 W

After BCCH TRX allocation

Example 1: 4+4+4 configuration with two RF Modules


62 DN09167685 Issue: 01F



Figure 16 Power budget

SCF Commissioning Data

Local Sector ID

Power/TRX

Assigned Antennas

AntennaType

LS-1

LS-2

LS-3

20W/TRX

20W/TRX

20W/TRX

(TX+RX)

(TX+RX)

(TX+RX)

FXxA1.1 - ANT-1

FXxA2.1 - ANT-1

FXxA1.1 - ANT-3

FXxA2.1 - ANT-3

FXxA1.1 - ANT-5

FXxA2.1 - ANT-5

BTS-41st TX Antenna

BTS-51st TX AntennaBTS-6

1st TX Antenna

BTS-62nd TX Antenna

BTS-52nd TX Antenna BTS-4

2nd TX Antenna

BSC Configuration

BCF-4

Sector ID AssignedTRX

ARFCN TRX Type

BTS-4

BTS-5

TRX-1

TRX-2

TRX-3

TRX-4

20

24

28

32

BCCH

TRX-5

TRX-6

TRX-7

TRX-8

50

54

58

62

BCCH

BTS-6

TRX-9

TRX-10

TRX-11

TRX-12

70

74

78

82

BCCH

RF Module FXxA 1.1

FXxA1.1-ANT-1 TRX-1TRX-2TRX-3

FXxA1.1-ANT-3 TRX-5

TRX-6TRX-7

FXxA1.1-ANT-5 TRX-9

TRX-10TRX-11

RF Module FXxA 2.1

FXxA2.1-ANT-1 TRX-4 32



+ =202428

505458

707478


Operability

Issue: 01F DN09167685 63



Figure 17 ARFCN effects


Local Sector ID

Power/TRX

Assigned Antennas

AntennaType

LS-1

LS-2

LS-3

20W/TRX

20W/TRX

20W/TRX

(TX+RX)

(TX+RX)

(TX+RX)

FXxA1.1 - ANT-1

FXxA2.1 - ANT-1

FXxA1.1 - ANT-3

FXxA2.1 - ANT-3

FXxA1.1 - ANT-5

FXxA2.1 - ANT-5

BTS-41st TX Antenna


1st TX Antenna

BTS-62nd TX Antenna


2nd TX Antenna

BSC Configuration

BCF-4

Sector ID AssignedTRX

ARFCN TRX Type

BTS-4

BTS-5

TRX-1

TRX-2

TRX-3

TRX-4

20

24

28

32

BCCH

TRX-5

TRX-6

TRX-7

TRX-8

50

54

58

62

BCCH

BTS-6

TRX-9

TRX-10

TRX-11

TRX-12

70

74

78

82

BCCH

RF Module FXxA 1.1

FXxA1.1-ANT-1 TRX-1TRX-3TRX-4

FXxA1.1-ANT-3 TRX-5

TRX-6TRX-8

FXxA1.1-ANT-5 TRX-9

TRX-11TRX-10

RF Module FXxA 2.1




+ =202428

505458

707478


64 DN09167685 Issue: 01F



Figure 18 Frequency budget


Local Sector ID

Power/TRX

Assigned Antennas

AntennaType

LS-1

LS-2

LS-3

20W/TRX

20W/TRX

20W/TRX

(TX+RX)

(TX+RX)

(TX+RX)

FXxA1.1 -ANT-1

FXxA2.1 -ANT-1

FXxA1.1 -ANT-3

FXxA2.1 -ANT-3

FXxA1.1 -ANT-5

FXxA2.1 -ANT-5

BTS-41st TX Antenna


1st TX Antenna

BTS-62nd TX Antenna


2nd TX Antenna

BSC Configuration

BCF-4

Sector ID AssignedTRX ARFCN TRX Type

BTS-4

BTS-5

TRX-1

TRX-2

TRX-3

TRX-4

640

600

660

650

BCCH

TRX-5

TRX-6

TRX-7

TRX-8

770

830

720

821

BCCH

BTS-6

TRX-9

TRX-10

TRX-11

TRX-12

580

729

679

681

BCCH

RF Module FXxA 1.1

Antenna

AllocatedTRX

ARFCN Freq Diff from BCCH

FXxA1.1-ANT-1

TRX-1TRX-4TRX-3

640650660

BCCH+ 2.0+ 4.0

FXxA1.1-ANT-3 TRX-5

TRX-7770720

BCCH- 10.0

FXxA1.1-ANT-5 TRX-9TRX-11

580679

BCCH+ 19.8

RF Module FXxA 2.1

Antenna

AllocatedTRX

ARFCN Freq Diff from BCCH

FXxA2.1-ANT-1 TRX-2 600 - 8.0


821830

+ 10.2+ 12.0


681729

+ 20.2+ 29.8

+ =

4.23.4 Alarms due to resource allocationThe major alarm 7606 TRX FAULTY - "TRX object allocation failed in RF Module" is

started due to the fault reason TRX object allocation failed in RF module when the

System Module fails to allocate TRX objects in the RF Module. Note that only in case of

inadequate resources, the resource allocation alarm is started. If there are excessive RF

resources they just remain unused and no alarm is started.

See Trouble Management of Flexi Multiradio BTS GSM/EDGE for more information on

fault reasons and troubleshooting instructions for alarms related to resource allocation.

4.23.5 Smart BCCH recovery

In the RF Module, Software Tunable Filters (STuF) support limited uplink and downlinkbandwidth. TRX resources are allocated on the basis of the frequency and power budget

of the RF Module antenna ports (pipes) as described in RF allocation procedure.

When the branch carrying the BCCH TRX gets faulty and when BCCH ARFN can not be

swapped with all of the remaining TRXs (in that sector), 7606 TRX FAULTY alarms are

started on all the TRXs of the working branch when BCCH TRX and its TCH TRXs move

is made. The TCH TRXs mapped to that branch and no alarms are started on the BCCH

TRXs.

In this example:


• Max power per branch = 60 W


Operability

Issue: 01F DN09167685 65




• 2 branches of 1800 MHz band in local sector

Figure 19 Smart BCCH recovery when interchangeability is not possible

If interchangeability is possible with all the non-BCCH frequencies then the BTS raises

the alarm on all TRXs of the broken branch including BCCH TRX, and BSC does a

BCCH reconfiguration with a healthy non-BCCH TRX. BTS then performs the ARFN

swap for these two TRXs as shown in the figure.

In this example:


• Max power per branch = 60 W


• 2 branches of 1800 MHz band in local sector


66 DN09167685 Issue: 01F



Figure 20 Smart BCCH recovery when interchangeability is possible

4.24 BSS21362 Fast BSS Restart

The “BSS21362 Fast BSS Restart” feature increases the network availability by reducing

the radio network (RNW) downtime in a controlled BSC restart. The reduced downtime is

achieved by restarting the BSC without an RNW restart. The feature is basic software

and its usage is not controlled by a license or parameter. Fast BSS Restart is not allowed

if RNW Plan or RNW Fallback activation is ongoing.

Usually, a BSS system restart is performed to ensure that all the necessary parameters

and information are updated inside BSC and BTS after a BSC software installation, or

during maintenance. During a BSS system restart, the cells go into a barred state for a

while causing downtime in the radio network. The BSC’s computer units become active

and start running depending on the BSC configuration. After that, the RNW takes 1- 82.5

minutes to get active, depending on the BTS site type, BTS software, size of radio

network configuration, and BTS configuration in the BSS.

With the “BSS21362 Fast BSS Restart” feature, after a BSC restart is triggered and

when all its BTSs support the feature, the RNW activation phase takes only 0.5 - 4.5

minutes after all the BSC computer units are raised back to working state. The time

taken depends on the size of RNW configuration in the BSC.


Operability

Issue: 01F DN09167685 67



This feature provides the following benefits:

• Increased network availability for service usage

• All BTSs under BSC support the feature

Requirements

• BSC S15


GF1.0

• NetAct OSS5.2 CD set 3

4.25 BSS21316 Flexi BTS Autoconnection

The feature “BSS21316 Flexi BTS Autoconnection” enables a faster, automatedintegration of new Flexi BTSs into the BSS network, eliminating the need to use a laptop,

and making the integration less prone to error. The main purpose of the “Flexi BTS

Autoconnection” feature is to allow the dedicated SCF data to be automatically

transferred from the BSC to the BTS during BTS commissioning. However, when there

are radio transmission hops, or when the PCM line is shared between BTSs, a laptop is

needed as a download device. For this automated BTS integration capability, the

supporting transmission connectivity must be in place. An integrated radio network

planning process enables further automation improvements. This feature is not

supported with Pseudowire Ethernet (PWE) and Packet Abis modes. This is a licensed

feature.

The Flexi BTS Autoconnection feature provides the following benefits to operators:

• Simplifies installation and reduces the rollout time for new Flexi EDGE BTSs,

improving the efficiency of installation teams. Consequently, the time to service is

reduced and revenue is increased

• During the maintenance phase (after the network rollout has been completed), the

feature continues to support the speeding up of BTS configuration modifications,

reducing errors and consequently reducing the operating costs

• Reduces the time required for installing radio hops

Requirements

• BSC S15


GF1.0

4.26 BSS101574: Air Path Loss Measurement

The feature, BSS101574: Air Path Loss Measurement introduces a method to calculate

the path loss in uplink and downlink directions and a new measurement which consists

of uplink path loss, downlink path loss and path loss difference between uplink and

downlink. The new measurement for the circuit switched channels can be used for radio

network optimization purposes. This feature is controlled by a BSC level on/off license.

Requirements


68 DN09167685 Issue: 01F



• BSC S15 EP1.2


GF1.0

4.27 BSS101583 Precise Rx Level Management

The specific measurement counters log more accurate details of both the Uplink and

Downlink Rx Signal Level for all TRXs within a cell. The object level is defined as TRX,

which may also be aggregated at the BTS or BSC level. The information provided is

similar to that available from the existing Rx Level Statistic Measurement, however,

instead of counters for six Rx level classes, all 64 Rx levels defined by 3GPP now have

their own individual counters through this feature.

The source information is provided by handsets, via the standard Measurement Reports

(MR) and Enhanced Measurement Reports (EMR), when they are allocated to a TCHchannel (whilst in CS dedicated mode). The PM counters are updated during a CS

Handover and upon the cessation of the CS call.


This new performance management enhancement provides more accurate and precise

measurement data, which may then be utilised to improve the network planning and

network optimisation processes.

4.28 BSS101584 Precise Timing Advance Management

The specific measurement counters log more accurate details of both the Uplink andDownlink Rx Signal Level for all TRXs within a cell. The Object Level is defined as TRX,

which may also be aggregated at the BTS or BSC Level. The information provided is

similar to that available from the existing Rx Level Statistic Measurement, however,

instead of counters for 6 Rx level classes, all 64 Rx levels defined by 3GPP now have

their own individual counters through this feature. The source information is provided by

handsets, via the standard Measurement Reports (MR) and Enhanced Measurement

Reports (EMR), when they are allocated to a TCH Channel (whilst in CS dedicated

mode). The PM counters are updated during a CS Handover and upon the cessation of

the CS call.


This new performance management enhancement provides more accurate and precisemeasurement data, which may then be utilised to improve the network planning and


4.29 BSS101585 Precise Power Level Management

The specific measurement counters log more accurate details of the power level

statistics for BTS and Handsets. The Object Level is defined as TRX, which may also be

aggregated at the BTS or BSC Level. Counters for 39 (23 Handset and 16 BTS) power

levels are available through this feature and they are updated for all voice call types.


Operability

Issue: 01F DN09167685 69




(MR) and Enhanced Measurement Reports (EMR), when they are allocated to a TCH

Channel (whilst in CS dedicated mode). The counters are updated during a CS handover

and upon the cessation of the CS call.





4.30 BSS101586 Adjacent Cell Rx Level Management

The specific counters log more accurate details of the adjacent cell Rx levels, reporting

various Rx level statistics for the serving as well as adjacent cells. The object level may

be defined as serving BTS and serving BTS coverage area. Counters for three Adjacentcell Rx level ranks, 64 Adjacent cell Rx level values, 51 Serving-Adjacent cell Rx level

difference and 121 Serving-Adjacent cell Rx level matrices are collected and available

through this feature. The maximum number of reported adjacent cells is 40 (which may

include defined cells and undefined cells). The adjacent cell Rx level measurement

objects are reserved in the sequence that the adjacent cells are reported - the first 40

adjacent cells reported are monitored whilst adjacent cells reported beyond this are

ignored.


(MR) and Enhanced Measurement Reports (EMR), when they are allocated to a TCH

channel (whilst in CS dedicated mode). The Counters are updated during a CS

Handover and upon the cessation of the CS call.





4.31 Power Cable Auto-detection

Flexi MultiRadio System Module (ESMB/C) has 4 PDU ports, which can be used to

supply power to the RF Modules connected to the System Module through optical

cables. RF Modules can draw power from the System Module’s PDU ports or from someexternal power supply. External power supply may be chosen when distance between

the System Module and the RF Module is quite long, or if the number of RF Modules

exceeds the number of available PDU ports (4) in the System Module.

The Power Cable Auto-detection feature provides the operator to connect the power

cables in any order and the software resolves the connectivity during commissioning. An

algorithm in the BTS software power cycles the PDU ports and resolves the connectivity

by checking the presence of the unit through optical signal. The outcome of this process

is written in the commissioning report. This feature is particularly useful when the RF

Module Power Down Feature is used. BTS software uses the PDU port which is mapped

to the RF Module to selectively switch off the 1800 RF Modules during low traffic to save

power.


70 DN09167685 Issue: 01F



The execution of this feature increases the time for the BTS to come to working state

during full commissioning. This is caused by the multiple iterations of switching on/off the

RF Modules to detect the connectivity. A known limitation of this feature is that if for

some reason the RF Module power cable or the optical cable was not connected, (full)

commissioning needs to be done again to resolve the power cables. Once the BTS is

commissioned, PDU port association of any hot inserted RF Module is not supported.

4.32 Antenna Hopping

Antenna Hopping feature is a further improvement for the performance of RF or BB

hopping. In antenna hopping, the BCCH frequency is fully hopping between 2 or more

antennas.

Antenna Hopping enables the TRXs in an RF hopping BTS to transmit with all the TX

antennas in the BTS. Antenna Hopping uses the existing baseband (BB) hopping

functionality in the BTS. In case of BB hopping, switching occurs in every frame whereas

in Antenna Hopping switching happens after 2 frames. In RF/BB hopping, the switching

point is Timeslot 0 and in case of Antenna Hopping it is Timeslot 4

Antenna Hopping can be used either with or without the RF hopping feature. With RF

hopping, cyclic and all random frequency hopping sequences can be used together with

Antenna Hopping. Antenna Hopping pattern will be automatically optimized based on the

frequency hopping sequence. The BCCH TRX is included in the Antenna Hopping

configuration, that is the BCCH transmission is moved from one antenna to another

antenna (TRX).

With Antenna Hopping, it is possible to achieve space diversity to the regular RF hopping

configuration, which means that there is a distance that separates two or more

transmitting antennas providing uncorrelated signals. At the MS, a separation of half a

wavelength is the minimum for obtaining uncorrelated signals. At the base station

frequency, the antenna height and antenna spacing make the correlation efficient.

Restrictions

The following functionalities cannot be used simultaneously with Antenna Hopping:

• BB hopping or DFCA hopping in the same BTS


• BCCH antenna VSWR measurement

Antenna Hopping is OFF in the BTS

• when TRX(s) are down

• if the number of working TRXs decreases below two TRXs per BTS

When Antenna Hopping is in use the following tests are not possible:

• the TRX test

• the TRX loop test

The minimum configuration for Antenna Hopping is two TRXs/cell where both TRXs are

used for Antenna Hopping. At least two antennas must be commissioned for the

minimum configuration. Note that site expansion by adding TRX(s) in an Antenna


Operability

Issue: 01F DN09167685 71



Hopping sector results in 7606 "TRX object allocation failed in RF Module" alarm for the

added TRX(s). A sector reset needs to be triggered after carrier addition to cancel the

alarm and reconfiguring the Antenna Hopping Group for the sector.

Benefits

The Antenna Hopping feature helps in avoiding network level interference and link level

frequency selective fading.

With this feature the user can achieve an average 2 dB gain on the link level. With low

antenna correlation, Antenna Hopping can gain 1.5 to 4 dB depending on the mobile

speed (typical urban, 3 to 50 km/h, no FH) compared to a single antenna.

Antenna Hopping also makes it possible to gain better network level spectral efficiency

on the BCCH layer. In a very narrow band environment (3.6 MHz), better network

capacity can be achieved by tightening the BCCH re-use (for example from 5/15 to 4/12)

without an extra TRX). By tighter BCCH re-use, more frequencies can be used in the

hopping traffic layer, thus providing better capacity for narrow band networks.

4.33 BSS101696 Small form-factor pluggable (SFP)Transceiver Diagnostics

The feature ‘BSS101696 Small Form-Factor Pluggable (SFP) Transceiver Diagnostics’ is

an Operability Enhancement feature to help improve maintenance and troubleshooting of

Optical Converter to Radio Module connections. This feature helps to fetch the following

real-time parameters of SFP:

• Optical output power • Optical input power

• Temperature

• Laser bias current

• Transceiver supply voltage

This information is updated in the BTS at periodic intervals and can be obtained from the

2G Flexi BTS Site Manager’s Site Information Report (SIR). Static information like

revision number of SFP is also available from this feature.

Benefits

• Improved troubleshooting of optical lines in the ESMx cards

• Lesser number of site visits

4.34 BSS20984: 2G TRX Automatic Power Down

The “BSS20984: 2G automatic power down” feature introduces an energy saving

mechanism for the BTS. This feature automatically shuts down TRXs when the traffic is

low. This feature is controlled with an ON/OFF license key in the BSC. The operator can

define the traffic limits for power down and power up at segment level. The TRXs are

automatically powered down and powered up when the respective traffic load limit is

reached. The statistics of the feature collect the cumulative down time for powered-down

TRXs.


72 DN09167685 Issue: 01F



The operator defines the traffic load limits for TRX power down and power up as two

segment level parameters. By means of a new parameter at BSC level, the operator

defines the power down supervision period to control the reaction speed of the TRX

power down procedure.

By default, the feature is off in a segment. The operator enables the feature in the

segment by setting the segment’s “2G TRX Power Down Threshold” parameter to a

value greater than 0.

The BSC follows traffic load in the segment level. The BSC starts to power down a TRX,

with intra-cell forced handover, when a segment’s traffic load remains below the

powerdown threshold level for the duration of the power-down supervision period. When

the traffic load again increases and exceeds the power-up threshold, the BSC

immediately starts the power up of a powered-down TRX.

TRX power down

The power down of TRXs is possible only in working TRXs. The following issues aretaken into acount when selecting TRXs to power down:

The following TRX configuration issues are taken into account when selecting TRXs to

power down.

• A TRX without GPRS territory is preferred to be powered down before a TRX with

GPRS territory.

• Non-BB hopping and non-antenna hopping TRXs are preferred to be powered down

before a BB hopping layer and antenna hopping BTS.

• In the segment environment, TCH TRXs in the non-BCCH BTS(s) are preferred to

powered down before TCH TRXs in the BCCH BTS.

• A TCH TRX is preferred to be powered down before an SDCCH TRX.

• TCH TRXs with the non-preferred BCCH TRX mark (PREF=N) are preferred to

powered down before TCH TRXs with the preferred BCCH TRX mark (PREF=P).

• A GPRS-disabled TRX (GTRX=N) is preferred to be powered down before a GPRS

enabled TRX (GTRX=Y).

• A TRX with less traffic channel capacity is preferred to be powered down before a

TRX with more traffic channel capacity.

The BB and antenna-hopping TRXs are not powered down one by one. The powerdown

procedure is performed in one step for an antenna hopping BTS, or BB hopping layer

TRXs. With the “Handover support for coverage enhancements”, “Enhanced coverage

by frequency hopping” and “Intelligent underlay - overlay” features, TRXs of a BTS are

divided in two layers that can perform BB hopping independently. These layers are

powered down independently when BB hopping is in use. The BSC software allowsadding and removing of TRXs to and from the Antenna Hopping layer without blocking

the corresponding layer. Power down can be done TRX by TRX for the Antenna Hopping

layer.

g If BB-hopping is in use, the following features are also needed to be activated before

BSS20984 can be used:

• BSS7064 Handover support for coverage enhancements

• BSS8037 Enhanced coverage by frequency hopping

• BSS7005 Intelligent underlay - overlay

• BSS6115 Directed Retry


Operability

Issue: 01F DN09167685 73



The power-down order in a BB-hopping BTS is as follows:

1. Non-BCCH layer is preferred for power down before BCCH layer.

2. Super-layer TRXs are selected before regular-layer TRXs in case of a BTS with no

BCCH TRX.

When the number of free traffic channels in the segment increases, then the BSC checks

the segments capacity. The threshold parameter indicates the number of traffic channels

that have to remain idle after the TRXs are powered down. The BSC starts a TRX power

down if the traffic loads in the segment remains low enough for a period of time defined

by the “2G TRX Power Down Supervision Period” parameter. The BSC requests the BTS

to power down the TRX. The TRX operative state is changed to “blocked for power

automatic power down”.

The GPRS channels are counted as reserved channels when checking the amount of

free traffic channels. The size of packet territory will remain the same even if the TRX(s)

are powered down. This will cause a situation that packet territory is relatively large

compared to CS resources.

During a 30-minute period after a system restart (including hot reset) the BSC does not

power down TRXs for power saving.

TRX power up

The power-up procedure is possible only for a TRX with operative state “blocked for

power automatic power down”.

The power-up procedure is done in reverse TRX id order than it is done in power down.

The baseband and antenna hopping are an exception to this rule. The hopping groups

are powered up last since they are powered down last.

The base band and antenna-hopping TRXs in “blocked for power automatic power down”state are powered up in one step (not one by one). With the “Handover support for

coverage enhancements”, “Enhanced coverage by frequency hopping” and “Intelligent

underlay-overlay” features, TRXs of a BTS are divided in two layers that can perform BB

hopping independently. These layers are powered up independently when BB hopping is

in use. Power up can be done TRX by TRX for the Antenna Hopping layer.

When the number of free traffic channels decreases, the BSC checks if capacity is below

the value of the “2G TRX Power Up Threshold” parameter. If capacity is below this value,

the BSC starts the power up. The BSC requests the BTS to power up the TRX. The TRX

operative state is changed to “WO”.


When this feature is activated in the network, the operator can lower the network

operating costs by reducing energy consumption.

Restrictions

Baseband Resource Sharing is not supported with BSS20984 2G TRX Automatic Power

Down feature.

4.35 RG301936: Intelligent MCPA TRX Shutdown

Introduction


74 DN09167685 Issue: 01F



The RG301936: Intelligent MCPA TRX shutdown feature is an enhancement to the

BSS20984: 2G TRX Automatic Power Down feature.

The Intelligent MCPA TRX shutdown feature improves the shutdown functionality of

power amplifier in MCPA BTS to save power during low traffic conditions. The 2G TRXautomatic power down functionality in BSC is improved so that TRX-MCPA association is

taken into account when TRXs are powered down and up. MCPA can be shut down as

soon as all TRXs connected to it have been powered down by BSC (upon no traffic).

g For FlexiCompact as external RFM module and support of external Flexi MR RFM

(FXxB), the handling of Intelligent MCPA TRX shutdown feature remains the same.

Even if TRX connected to MCPAs on the integrated RFM are shutdown, the

corresponding PA are not shutdown as FlexiCompact houses a System Module.

The feature is controlled by ON/OFF license key.

The BSC controls the functionality of this feature with the following parameters:

• 2G TRX Power Down Supervision Period - BSC level.

• 2G TRX Power Down Threshold - segment level.

• 2G TRX Power Up Threshold - segment level.

For more information see the BSS20984: 2G TRX automatic power down feature. The

BSC selects TRXs to be powered down and up based on traffic and instructs the BTS to

power down and power up the TRXs. BTS shuts down the PA when all the TRXs are

powered down. The TRXs of MCPA BTS are associated with certain MCPA units.

Maximum number of TRXs per MCPA unit is six.

TRX power down based on TRX-MCPA association

TRXs connected to the BCCH MCPA or MCPA shared with other technologies or MCPA

with ETRXs are not powered down. If MCPA is shared with other technologies BTS

reports that to BSC. TRXs connected to the other MCPAs are powered down so that the

MCPA with least working TRXs is preferred. This way the PAs are shutdown as soon as

allowed by the traffic.

The MCPA Priority is considered while powering down TRXs connected to different

MCPAs. The MCPA Priority from the lowest to the highest order are shown below:

• A GPRS-disabled TRX (GTRX=N) is preferred to be powered down before a GPRS

enabled TRX (GTRX=Y).

• TCH TRXs with the non-preferred BCCH TRX mark (PREF=N) are preferred topowered down before TCH TRXs with the preferred BCCH TRX mark (PREF=P).

• An MCPA with more powered down TRXs is preferred to an MCPA with less powered

down TRXs.

• A TCH TRX is preferred to be powered down before an SDCCH TRX.

• In the segment environment, TCH TRXs in the non-BCCH BTS(s) are preferred to

powered down before TCH TRXs in the BCCH BTS.

• Non-BB hopping and non-antenna hopping TRXs are preferred to be powered down

before a BB hopping layer and antenna hopping BTS.

• A TRX without GPRS territory is preferred to be powered down before a TRX with

GPRS territory.


Operability

Issue: 01F DN09167685 75



In the following figure TRXs in MCPA 2 has the highest number of TRXs in powered

downstate, hence BSC first prefers the TRXs in MCPA2 and then TRXs in the MCPA3 for

power down. BSC does not select the TRXs in MCPA1 as it has an associated BCCH

TRX.

Figure 21 TRX power down based on the MCPA priority

BTS 1

TRX 1 (BCCH)

TRX 2

TRX 3 (BL-PWS)

TRX 4

TRX 5

TRX

TRX 1 (BCCH)MCPA 1

MCPA 2

MCPA 3

The following TRXs cannot be used for power down by this feature:

• TRXs from MCPAs having a BCCH TRX

• TRXs from MCPAs having Extended TRXs

TRX power up based on TRX-MCPA association

BSC powers TRXs up in reversed order of TRX power down. BSC first prefers the MCPA

with BCCH TRX connection when possible configuration changes of MCPA occur, for

example BCCH swap from one MCPA to another while TRXs are in powered down state.

Requirements

Software Rquirements

Table 8 Software requirements for different network elements

Network Element

Software release

BSC S16.1

BTS EX 5.1, GF1.0 or GFC1 1.0.0

Hardware Requirements


76 DN09167685 Issue: 01F



Table 9 Hardware requirements for different network elements

Network Element

Required hardware

BSC BSC3i, Flexi BSC

BTS Flexi Multiradio BTS

GSM/EDGE, Flexi Multiradio 10

BTS or Flexi Compact BTS

Restrictions

Basic functionality of Intelligent MCPA TRX shutdown feature remains the same with the

following exception related to internal RFM module:ul

• Even if TRX connected to MCPA)s) on the integrated RFM are shutdown, the

corresponding PA are not shutdown as FlexiCompact also houses a System Module.

• BSS20984 2G TRX Automatic Power Down feature

The feature BSS20984 2G TRX Automatic Power Down feature license is needed to

activate Intelligent MCPA TRX shutdown feature.

• Shared RF configurations

If the RF configuration of the MCPA is shared with other technology, BSC does not

power down the TRXs.

• RG301794 BSS support for Baseband Resource Sharing

BSS support for Baseband Resource Sharing feature cannot be activated

simultaneously with Intelligent MCPA TRX shutdown feature.• Extended Cell range

The Intelligent MCPA TRX shutdown feature does not support the extended and

super extended area TRXs. An MCPA with atleast one extended or super extended

area TRX connected to it cannot be shut down.


Baseband hopping TRXs are not powered down one by one. Power down is

performed for all those TRXs that are possible to power down at same time and not

one by one. If Baseband hopping TRXs are distributed between a BCCH MCPA and

non BCCH MCPA or RF shared MCPA and non BCCH MCPA then TRXs in the

BCCH MCPA and RF shared MCPA are never powered down. Power up is

performed for all powered down TRXs at same time.

• RG602124 Composite Multi Site TransmissionThe Intelligent MCPA TRX shutdown feature does not support the Composite Multi

site cell. The operators should not activate 2G TRX Automatic Power Down in

Composite Multi site cells.

• Common BCCH and Multi BCF

BSC measures the traffic amount in segment level. For power down the TCH TRXs

in the non-BCCH BTS(s) are preferred to power down before TCH TRXs in the

BCCH BTS. For power up the TCH TRXs in the BCCH BTS are preferred to power

up before TCH TRXs in the non-BCCH BTS(s).

• Optimized antenna configuration

This feature usage is limited when using optimized configuration for antennas.


Operability

Issue: 01F DN09167685 77



4.36 BSS101688 BSS support for FSM3

BSS101688 BSS Support for FSM3 (FSMF) is a feature that brings BSC and NetAct

support for Flexi Multiradio 10 BTS. Flexi Multiradio 10 BTS is new site type that is

capable of implementing 2G, 3G and LTE radio standards in the same System Module.

Feature is needed to provide BSC and NetAct support for FSM3 BTS. FSMF is a new

System Module platform.

4.37 BSS10104 Intelligent Downlink Diversity

The auxiliary transceiver and antenna diversity gain is applied in downlink by using a

feature called Intelligent Downlink Diversity (IDD). In the IDD, the cell coverage area is

extended by sending the same downlink signal through two transmitters simultaneouslyfor additional signal power. The auxiliary transmitter introduces controlled delay and

hopped phase to the original signal for additional diversity gain. As a result, the auxiliary

transmitter doubles the transmitted signal power and creates an artificial, independently

fading multipath propagation component, which can be resolved by any legacy mobile

station receiver. Increased signal power and diversity gain will improve the performance

of all physical radio channels and timeslots for different propagation conditions. All

logical traffic and control channels in all radio timeslots are transmitted through two

transceivers, which are connected to spatially separated antennas. Also, the BCCH

carrier is transmitted through two transceivers for enhanced BCCH coverage. The IDD

boosts downlink performance by 3 dB due to doubled transmitted signal power obtained

from the auxiliary transceiver. Additional 2 to 3 dB diversity gain can be added, resulting

thus in 5 to 6 dB gain in average for radio timeslots. The IDD is an ideal method for adual X-polarised antenna concept providing major capacity, coverage and quality

enhancements with added data throughput.

g IDD configurations with 2UD or 4UD receiver configurations are only supported with

oddly numbered TRXs : 1,3, 5…35. However GF1.0 release has a limitation in

performance (for example only one transmitting antenna is supported) for odd TRXs

3,9,15,21,27,33, so the user is guided not to configure them. Otherwise configuration

and performance boost of IDD TRXs is similar to fleximulti BTS.

4.38 RG301980 CMST Support with FSM3Feature RG301980: CMST Support with FSM3 supports Composite Multi Site

Transmission (CMST) on FSMF. It is extended version of RG602124: Composite

Multisite Transmission feature that supports CMST on FSMB/C. This feature enables

combining of 2 - 12 RRHs in one cell to reduce handover between cells by creation of

one single logical cell.

Possible configurations:

• 1 to 12 TRX objects with chain depth of 1...6 RRH nodes

• 2 to 6 TRX objects with chain depth of 2...12 RRH nodes


78 DN09167685 Issue: 01F



5 Site solutions

5.1 BSS10046 Multi BCF Control

The cell capacity can be increased with the Multi Base Control Function (BCF). Multi

BCF is an application software product that allows combining resources of several

physical base stations into one logical cell. Flexi Multiradio BTS cell capacity can be

increased up to 108 TRXs with Multi BCF/common BCCH. For more details, see

GSM/EDGE BSS, BSC and TCSM Product documentation. Multi BCF also provides a

path for site expansion from Nokia UltraSite EDGE BTS to Flexi Multiradio BTS

GSM/EDGE.

Multi BCF Control requires that BSS9055 Clock Synchronisation between base stations,

or BSS10069 Synchronized BSS is used.

The operator can arrange base stations so that the TRXs in different base stations

(operating on the same frequency band) can serve the same cell with a single BCCH. At

the base station site, the operator needs to make some installations, for example

synchronisation is needed between the base stations. All the base stations will have a

separate O&M link to the BSC. At the BSC, a SEGMENT (SEG) object must be used to

set all the BTS objects sharing the same BCCH.

Figure 22 Multi BCF configuration

Multi BCF cell (= SEG)

f1 f2 f3

f4 f5

UltraSite TRX group

Flexi TRX group

5.2 BSS9055 Clock Synchronisation between BaseStations

Clock Synchronisation between Base Stations enables synchronous handovers between

base stations. The sectors defined to different base stations can use common hopping

frequencies with RF hopping, which increases the channel capacity. The maximum site

configuration is nine Flexi Multiradio BTSs in a chain.The Flexi Multiradio Base Station has an external clock interface that can be used to

synchronize the air interface between several Flexi Multiradio Base Stations located on

one site.

When several Flexi Multiradio Base Stations are synchronized, the master base station

(master BTS) functions as the frame clock source to the slave BTSs. The master BTS

transmits the frame clock and frame number signals to the external clock line, while the

other BTSs (slave BTSs) receive these signals. The slave BTS uses the received frame

clock signal as a reference clock signal to adjust its main frequency source. The master

BTS uses the reference clock signal derived from the Pulse Code Modulation (PCM)

signal.


Site solutions

Issue: 01F DN09167685 79



It is possible to synchronize a Flexi Multiradio Base Station to a Nokia UltraSite EDGE

BTS to serve the adjacent sectors. In this case the clock master is always a Nokia

UltraSite EDGE BTS.

In Pseudowire Emulation (PWE) mode, the following synchronisation sources areoffered:

• Adaptive clock recovery based on a PW

• Synchronisation via E1/T1

• Synchronisation via 2 MHz input (ITU-T G.703)

• Synchronisation to a system reference clock (that is, a clock used by the BTS like a

GPS)

• 1 Pulse Per Second (PPS) signal as external sync source

The performance of the adaptive clock recovery is very much dependent on the

performance of the packet-switched network. It is recommended to trial use the adaptive

clock recovery for gaining information about if the network performance is sufficient for this option.

Physical properties

The maximum cable length for the total system is 100 meters. The synchronisation chain

between the BTSs is made using RS-485 connection for the transferred clock signals.

Synchronisation recovery

If there is a failure in the synchronisation between the base stations, the slave BTS

generates an alarm and the BSC then blocks all TRXs of the alarming BCF. When the

fault disappears, cancellation to the alarm is sent to the BSC. The BSC then unblocks

the TRXs under the alarming BCF object.

Fast tuning

• If the clock reference is taken from Abis:

If the BTS is being commissioned, the fast oven-controlled crystal oscillator (OCXO)

tuning is executed for the maximum duration of 8.6 seconds. The target accuracy is

0.02 ppm. The adjustments can be 10 times larger than in normal tuning. After fast

tuning, the BTS starts normal tuning, and allows the BTS configuration to be

completed.

• If the clock reference is taken from an external synchronisation source (other BTS or

LMU):If the BTS is being commissioned, the fast OCXO tuning is executed for an indefinite

duration until the target accuracy of 0.02 ppm is met. Typically, the external clock

reference is stable, therefore the fast tuning is completed in 36.92 seconds (eight

rounds). The adjustments can be much larger than in normal tuning. After fast tuning,

the BTS starts normal tuning, and allows the BTS configuration to be completed.

When an already commissioned BTS is started, the BTS starts performing fast tuning

and starts configuration on TRXs. Since fast tuning configuration on TRXs are

running in parallel, there is a possibility of handover failures for approximately one

minute. However, this failure is seen only when the slave BTS is started with

calibrated DAC word which is far from the stable value. No handover failure is seen

when the slave BTS is started with stable calibrated DAC word.

Site solutions Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

80 DN09167685 Issue: 01F



• With PWE and the adaptive clock recovery as the Abis synchronisation source, the

performance of the lock-in to adaptive clock recovery will take approximately 10

minutes, but depending on the condition of the packet-switched network, can take

considerably more time. The BTS will wait at commissioning until the lock-in is

achieved before continuing with fast tuning.

If the commissioning is aborted due to exceeding lock-in time allowance, the BTS will

continue to achieve the lock-in and proceed to supervisory mode.

Normal tuning

With Abis as reference, the digital-to-analogue converter (DAC) word adjustment may

occur every 20 minutes. The purity of Abis is monitored continuously, and the adjustment

is only performed if the purity is good enough.

With an external clock as reference, the DAC word adjustment may occur every 20

minutes. The presence of the external clock source is monitored, the purity is not. When

the external clock is present, the adjustment is made.

With both clock sources, the current DAC word is written as a new calibrated DAC word,

if the current DAC word eventually drifts far enough from the calibrated DAC word. This

ensures that in later start-ups (in any environmental conditions), the BTS starts

immediately with a value as accurate as possible, and the C-plane and U-plane signaling

and traffic remain undisturbed.

With PWE and the adaptive clock recovery, it is possible to use the 4th E1 interface for

relaying synchronisation to, for example, a co-sited BTS. This output is compliant to

wander network interface requirements (ITU-T G.823). By not adhering to the

synchronisation interface requirements, the output should only be used for a BTS

synchronisation application.

If the adaptive clock recovery synchronisation source is lost due to a degraded packet-switched network, the BTS will use a high stable OCXO for hold over. For approximately

13 minutes, the BTS is still showing the adaptive clock recovery as the synchronisation

source and does not raise an alarm, filtering those short term intermediate disturbances.

5.3 1 Pulse Per Second (PPS)

A 1 Pulse Per Second (PPS) signal, generated from any source like a GPS receiver, can

be fed to the SYNC IN connector of the System Module. This signal can then be used as

a clock source for tuning the System Module OCXO. Since no frame number is encoded

in the signal, just the BTS frequency/phase can be synchronized to this clock source.

The required frame number and frame clock are generated BTS internally.

5.4 BSS10069 Synchronized BSS

With Synchronized BSS, all the clocks of the different sites in the network are

synchronized, so that the GSM frame timing is aligned between all sites.

This is done by using a Location Measurement Unit (LMU) or other GPS Devices, such

as, FYGB. These devices gets a GPS time reference, and uses this to generate clock

signals for the BTSs.


Site solutions

Issue: 01F DN09167685 81



Synchronizing all BTS sites in the network minimizes timing differences between TDMA

bursts of different sites. The benefits are:

• Improved quality (higher data throughput, lower frame error rate (FER))

• Possibility of tighter frequency reuse

• More effective cell re-selection and handover processes

• More accurate MS locationing functionality

5.4.1 BSS20371 BSS Site Synchronisation RecoveryImprovement

BSS Site Synchronisation Recovery Improvement is an enhancement to BSS11073

Recovery for BSS and Site Synchronisation. With BSS Synchronisation Recovery

Improvement, the BTS site continues in the BSS Synchronized service even if the GPS

coverage is lost for up to 12 hours. The BTS site also continues in the BSS

Synchronized service throughout an LMU software update.

The transmission link(s) to the BTS site meet the Jitter and Wander requirements of

ANSI T1.403 for T1 links, or ITU G.823 for E1 / 2048 kbit/sec hierarchy links.


Improved BSS Synchronisation Recovery is used in any networks which use BSS

Synchronisation.

5.4.2 BSS11073 Recovery for BSS and Site Synchronisation

The main purpose of Recovery for BSS and Site Synchronisation is to give automatic

recovery for BSS Synchronized sites (sites with LMU) if the BSS 20371 Site

Synchronisation recovery improvement is not used.

• when the Location Measurement Unit (LMU) clock signal is lost, to get the chained

BTS cabinet (site) into unsynchronized mode

• when the LMU clock signal is again available, to return the chained cabinet back into

Synchronized mode

Recovery for BSS and Site Synchronisation also offers synchronisation recovery for a

Multi BCF site using BSS9055 Clock Synchronisation.

When the BTS chain is defined in the BSS radio network database, Recovery for BSS

and Site Synchronisation automates the recovery if the BTSs in the chain are

Synchronized and the clock signal is lost and regained. On the other hand, if the chain is

not defined or the BSS or Site synchronisation of the chain has not been activated, the

sites need to be locked and unlocked in the correct order to enable system

synchronisation. The BSC receives the information for recovery from Q1 and BTS

alarms.


82 DN09167685 Issue: 01F



Figure 23 Synchronized BSS example in Flexi Compact BTS chain

BSC

LMU(master)

BTS(Flexi)(slave)

IN OUT

Abis

FN Offset

Q1

FN, FCLK

BTS2(Flexi)(slave)

IN OUT

BTS3(Flexi)(slave)

IN OUT

FN, FCLK FN, FCLK

The BSS is Synchronized by a Global Positioning System (GPS), that is, LMUs are

installed to every site with GPS antennas. The clock source is a GPS satellite via the

LMU. When the LMU feeds the clock, all BTSs are working as slaves. When the LMU

clock feed is lost, the BSC starts a timer. The Synchronized operation continues

uninterrupted based on the BTS internal clock. If the BSC timer expires, the first BTS in

the chain becomes a clock master and starts supplying the clock signal to the other

BTSs. The BTS synchronisation status indication in the BSC is changed to

'unsynchronized'. When the LMU clock is recovered, the BTS becomes Synchronized

again.

Benefits

Automatic recovery for the loss of LMU clock, when the BTS chain is defined in the BSS

radio network database:

• Automatic BSC-controlled recovery to unsynchronized operation

• Automatic BSC-controlled return to Synchronized operation

• Timeslot offset parameter sending to LMU

• BTS synchronisation configuration and mode information available from the BSC by

MML and NetAct

LMU can be connected to a legacy BTS, such as, ESMA/B/C and provide FCLK/FN to

Flexi Multi Radio 10 BTS. LMU can not be directly connected to Flexi Multi Radio 10BTS. FYGB is connected to a Flexi Multi Radio 10 BTS for BSS synchronization. Such

sites with no LMU can still continue synchronized operations uninterrupted based on the

BTS internal clock.

5.5 Operating bands

Flexi Multiradio supports the following operating bands with RF Module (FXxx):


Site solutions

Issue: 01F DN09167685 83



Table 10 Flexi Multiradio RF Module variants

Version

Description

FXCA 850 band 70 W

FXCB 850 band 90 W

FXDA 900 band 70 W

FXDJ 900 J-band (for CDMA co-siting) 70 W

FXDB 900 band 90 W

FXEA 1800 band 70 W

FXEB 1800 band 90 W

FXFA/FXFB 1900 band 70 W

FXFC 1900 band 90 W

Flexi Multiradio supports the following operating bands with RRH Module:

Table 11 Flexi Multiradio RRH Module variants

Version

Description

FHDA 900 band 2x40 W

FHDB 900 band 2x60 W

FHEA 1800 band 2x40 W

FHEB 1800 band 2x60 W

Dual and Tri Band Common BCCHCommon BCCH allows the combination of two or more sectors into a single logical cell,

with a single BCCH carrier. With common BCCH sectors in different frequency bands

such as 900/1800 MHz (or 800/1900 MHz, or 800/1800 MHz) can be configured with a

common BCCH carrier.

The main advantages of the common BCCH functionality are:

• Improved trunking gain

• Use of signaling channels is optimized by sharing them between bands

• Tighter reuse of all carriers in the non-BCCH bands

• Better call quality because of decreased number of handovers


84 DN09167685 Issue: 01F



To ensure proper operation of the network, take into account issues related to the

difference of propagation between the different bands when performing cell planning.

Figure 24 Common BCCH configuration

Common BCCH cell

f1 f2 f3

f6 f7 f8

f4 f5

PGSM 900 TRX group

EGSM 900 TRX group

GSM 1800 TRX group

Frequency hopping between bands in the same sector is not supported.

5.6 BTS2043 BTS External Alarms and Controls (EAC)

With external alarms and controls, alarms can be sent from external equipment attached

to the BTS. External alarms and controls also allow control of these external equipment

attached to the BTS. External Alarms caused on the site, such as the intruder alarm, are

sent to the BSC and NetAct via the Abis.

The EAC connector on ESMB/C modules have 12 alarm input and 6 control output lines.

By using optional FSEB Alarm Extension module, the number of alarm input lines can be

extended up to 24. The use of both input and output lines are defined on BSC. In

addition, FPA connector on ESMB/C modules can then be used to monitor up to 6 BBU

related alarm input lines. The use of these lines are defined on BTS Manager during

commissioning.

EAC connector on RFM and RRH modules have 4 alarm input lines. The use of these

lines are also defined on BTS Manager during commissioning. The alarm input lines are

TTL level signals, all referred to 5 V. The operator can define whether an alarm is raised

when the alarm input line is grounded or disconnected from the ground potential (this is

known as alarm polarity). This allows more flexibility for the alarming device.

The External Controls allow the user to control external equipment remotely from the

BSC. The External Controls are of open-collector type and typically used to control

external opto-couplers.

g EAC inputs 7…12 are multiplexed with EAC outputs, so that only one can be configured

at a given time. BSC supports then defining of the EAC output into “not used” state.

5.7 BTS2020 RX antenna diversity

The BTS receive sensitivity especially in fading conditions can be improved with

multipath receive diversity. 2-way diversity requires at least two antennas for each sector,

one for both main and diversity Rx-signals. 2-way diversity also requires a receiver for

each antenna, that is, at least two receivers. The 3-branch RF Module is optimized for 2-

way diversity. The module has a diversity RX path in addition to the main RX path in

each radio pipe. So, 2-way diversity can be configured in the RF Module without any

additional BTS HW.


Site solutions

Issue: 01F DN09167685 85



Diversity is defined for every sector separately from the BSC.

5.8 BTS configurationsFlexi Multiradio BTS is a cost optimized solution for single mode GSM/EDGE, WCDMA,

or LTE networks or mixed multimode networks, enabling a smooth evolution between

different network technologies. Flexi Multiradio BTS can be used for high capacity as

well as high coverage macro or micro cellular applications, feederless sites, and mast

top installations.

It has a 3-branch RF Module optimized for traditional BTS sites with or without cabinet

installations. The RF Module is capable of serving 3 sectors with multimode multicarrier

radios of up to 60W output power/branch. The GSM/EDGE configuration supports up to

6 sectors with 36 carriers (one BCF object).

Flexi Multiradio also uses the Radio Remote Radio Head (FHxx) or RRH, which is a two-branch multicarrier, multi-standard radio transceiver module. Each branch consists of a

transmitter and receiver chain. It is intended for outdoor mounting and optimized for

feederless applications. The module consists of two independent branches, capable of

transmitting and receiving signals of multiple radio technologies concurrently with up to

six GSM carriers.

5.8.1 Dedicated mode

In Dedicated Mode, the radio module of the Flexi Multiradio operates purely in a single

radio technology. In a dedicated 2G mode, the RF Modules (FXxx) are connected

directly to the 2G System Module (ESMB/C).

Figure 25 Flexi Multiradio BTS in dedicated mode

ESMx

Fxxx

Fxxx

FxxxFSMx

5.8.2 Concurrent mode

In Concurrent mode or RF sharing mode the radio module of the Flexi Multiradio is

shared between radio technologies which are operating in 2G and 3G simultaneously. In

concurrent mode, the RF Modules (FXxx) are connected directly to the 2G system

module (ESMx) and the 3G system module (FSMx) and the system modules are

synchronised to each other.


86 DN09167685 Issue: 01F



Figure 26 Flexi Multiradio BTS in concurrent mode

FSMx

FSMx

RFM

RFM

RFM

with GSM

g Note that maximum number of shared RFMs is three.

5.8.3 Shared RX diversity

Rx diversity sharing between WCDMA and GSM/EDGE is achieved with two RF

modules, one dedicated to WCDMA and one dedicated to GSM/EDGE. This feature

enables operators to reduce site complexity, reduce site upgrade costs and to reuse

existing antenna systems.The RF modules are connected together using cable kit

472454A “RDSA Rx Diversity Sharing Kit 2m”.

Figure 27 Basic configuration with RX diversity sharing

FXDATx/Rx

Rx

RxOut

FXDATx/Rx

Rx

RxOut

FSMF

FSMx

Abis

Iub

1+1+1@60W3+3+3@20W6+6+6@10W

1+1+1@40W2+2+2@20W

3+3+3@20W

1

2

3

1

2

3

5.8.4 Antenna-optimized configurations

In Flexi Multiradio BTS it is possible to minimize the amount of antennas required by

using the “antenna-optimised” 2UD configurations.In these configurations, the RX

Diversity samples are automatically cross-connected between the RF branches in the RF

Module. This only happens if all TRXs (in the same sector) are within the STuF (Software

Tunable Filter) bandwidth of 20 MHz for GSM900 band or 30 MHz for GSM1800 band

and the antenna count for each branch is reduced to 1 antenna (that is, the TX/RX

antenna).If the TRXs are spread further apart (more than 20 MHz for GSM900 or more

than 30 MHz for GSM1800), then antenna optimisation is not used and 2 antenna

feeders for each branch are required (that is, TX/RX and RX).


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The following table lists the antenna-optimized configurations supported with Flexi

Multiradio BTS:

Table 12 Antenna-optimized configurations

Configurations

# of FXxx

# of

ESMB/C

# of

FPAA1)2)

# of

FPDA1)

Total number

of antennas

One RF Module

antenna-optimized

2 up to 12 OMNI

2UD

1 1 2 1 12

Two chained RF

Modules antenna-

optimized 2+2+2 upto 12+12+12 2UD

2 1 3 2 12

Three chained RF

Modules antenna-

optimized 3+3+3 up

to 12+12+12 2UD

3 1 4 2 18

5.8.5 Feederless configurations

In a feederless Flexi Multiradio BTS site, the RF module can be installed at a distance

from the System Module. This reduces the site investment and increases the RF

performance as the antenna feeder lines are shorter or not needed at all when the sitelocation is easy to access. BTS antenna line feeders are replaced with optical fiber

connections. Flexi Multiradio BTS has compatible optical OBSAI interfaces in the System

Modules and separate optical converters are not required.

For RF sharing the 300 m cumulative, maximum distance is supported irrecpectively of

fiber cable/SFP type.

When DC is fed from the DC power system to the RF Module, the maximum distance is

100 m (measured from the power system equipment to the RF Module input). The BTS

site can be either DC or AC powered (this concerns all the modules that require 48 V

DC). In the latter case, an AC/DC converter (either the FPMA or a 3rd party converter) is

required and the maximum length of the optical cable to be used is 200 m.

For information on installation distances see the Creating Flexi Multiradio BTS

GSM/EDGE feederless site configurations document.

1) Optional depending on the external power source. The number of power modules is based on maximum

power consumption and does not account for redundancy.2) One FPMA supports up to four FPAAs. FPBAs may also be installed in the FPMA. See Installing Flexi

Multiradio BTS GSM/EDGE Optional Items for more details.


88 DN09167685 Issue: 01F



Figure 28 Feederless rooftop site

Central location(System Module,Power system)

Sector Antenna

Sector Antenna

RF Module

5.8.6 Maximum configuration supported

The largest configuration achievable with Flexi Multiradio BTS GSM/EDGE is a

36+36+36+36+36+36 configuration using Multi-BCF.

In this configuration, 6 clock chained (FCLK and FN) ESMB/ESMC are required,

although up to nine BCFs in the following combinations can be clock chained together:

Table 13 BTS combinations and sync cables

Combination of BTS

Synchronization cable used

Flexi Multiradio – Flexi Multiradio ESFA

Flexi Mulitradio – Flexi EDGE ESFA

Flexi EDGE - Flexi Mulitradio ESFA

EDGE UltraSite - Flexi Multiradio ESUA

EDGE UltraSite - Flexi EDGE - Flexi

Multiradio

ESUA / ESFA

EDGE UltraSite - Flexi Multiradio - Flexi

EDGE

ESUA / ESFA

A 108 TRX Flexi Multiradio configuration can be constructed as follows:


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Figure 29 108 TRX configuration

Sync In Sync OutESMC

RFM 118TRX@10W

RFM 218TRX@10W

36 36 36

BCF1 BCF2 BCF3 BCF4 BCF4 BCF5

Local Sector Scheme

RFM1

RFM2

6 6 6

666

Each 36 TRX segment is created by segmenting a 12+12+12 configuration as follows:

BCF1 = 12+12+12 (requires 1 ESMC, 2 RFM)

For instructions for expanding and changing Flexi Multiradio configurations, see

Changing Flexi Multiradio BTS GSM/EDGE configurations.

5.9 Remote Electrical Tilt (RET)

Remote Electrical Tilting (RET) provides increased efficiency for optimization and

minimized site visits, as antenna tilting can be arranged by electric means remotely.

Antenna tilting also has impact on network performance, for example, on cell capacity,

due to other cell interference, soft handover overhead and coverage probability. This

feature is supported for configurations in concurrent mode only.

The reduction of interference for network efficiency and performance enhancement

requires a careful adjustment of the vertical antenna tilt during network deployment

(initial tuning), network expansion, troubleshooting, and network optimization. The

possibility of remote adjustment of the antenna tilts increases the flexibility during the

different network deployment phases by offering the possibility of several fine-tuning

cycles.


90 DN09167685 Issue: 01F



2G Flexi BTS Site Manager displays the commissioned RET devices and cannot

commission the tilt angle for the RETs. See Commissioning Flexi Multiradio BTS

GSM/EDGE document and See Nokia Product Information Center, Antenna Systems,

Operating Documentation for more information about RET.

5.10 MHA types supported

Flexi Multiradio BTS GSM/EDGE broadly supports the following types of MHA:

• AISG 2.0

• MOTOROLA 7.68

• Non-AISG 2.0

These can be configured using the 2G Flexi BTS Site Manager antenna settings screen.

g The MHA and/or RET cannot be used on GSM dedicated Pipes on a shared Radio

Module.

5.11 RG301397 Co-siting with BS2xx

The feature "RG301397 Co-siting with BS2xx" extends the support of BSxx to the Multi

BCF implementation described in BSS10046 Multi BCF Control by allowing co-siting of

BTSplus BTS with Flexi EDGE BTS or Flexi Multiradio BTS. The baseline of this feature

is the "BSS21469 BS2xx@Flexi BSC product family" feature that already interfaces

BS2xx to Flexi BSC.The aim of this feature is to allow site capacity extension by deploying new TRXs, and to

provide BR operators with features that are no more developed in the BR line. In a co-

sited configuration, the Flexi BTS is always placed before BTSplus in a common

transport E1/T1 chain. Antenna equipment, TMA/MHA modules and RF cabling are

shared by BTSplus and Flexi BTS in order to accomplish RX diversity, whereas for

transmission, dedicated antennas are used. The (common) BCCH carrier is configurable

both, in the Flexi BTS and BTSplus BCF.

In order to support Abis over IP/Ethernet (Pseudo Wire Emulation PWE) in a co-siting

scenario it is necessary that Flexi BTS performs the PWE/TDM conversion (described in

BSS21443 Packet TRS for UltraSite/BTSplus). In this scenario, no impacts are foreseen

on the BTSplus BTS.The benefits of this feature are:

• This feature allows the deployment of Flexi EDGE BTS or Flexi Multiradio BTS at

existing BTSplus sites in a co-sited configuration. Segments (radio cells) are

composed of transceivers belonging to both BCFs

• Investment savings for BR operators who may further use existing BTSplus TRXs

while adding Flexi BTS both in order to accomplish site capacity expansion and in

order to provide users with new features

Requirements

• BSC S15 EP1.2



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5.12 RF Module/RRH chaining

RF chaining can be done for Flexi Multiradio RF Modules/RRH. There are four optical

ports on the System Module which can be connected to up to four Radio Modules using

optical cables, in unchained configurations. Operators can increase the number of

supported Radio Modules by introducing chaining configurations. Chaining configuration

can support up to three Radio Modules in a single chain. This minimizes the optical cable

requirement for distributed/remote island sites and reduces the complexity of network

deployment.

Benefits

• Cost saving by minimizing the optical cable requirement

• Simplified and easy deployment

• Increase in capacity by adding up to six radio with one GSM/EDGE System Module

Software requirements

• Flexi Multiradio GSM/EDGE BTS software EX3.1 MP2.0 or Flexi Multiradio 10 BTS

GF1.0

Other supported configurations

• 850/1900 RFM chaining EDGE BTS software EX3.1 MP2.0

• Chained RRHs and chained RF Modules when connected to separate optical ports

• Mixed RFM-RRH usage in a single chain

Restrictions

• Antenna optimized configurations with RFM - RFM distance greater than 200 m is

not supported

• Maximum distance between System Module (ESMB/C) and the farthest Radio

Module (FXxx/FHxx) in a chain is 40 km

g There is a special case under CMST cell, that a single chain can have up to 6 RRHs

supported.

5.12.1 GSM - RF Module chaining

The following are the supported GSM RF Module chaining configurations:

Table 14 GSM RF Module chaining configuration

Chaining Type

Configuration

Distance

between

ESMB/C and

FXxA

Distance

between

FXxA 1 and

FXxA 2

Distance

between

FXxA 2 and

FXxA 3

Single chain of

three RF Modules

3/3/3@60 W to

9/9/9@20 W

upto 10 km 1 km 1 km


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Table 14 GSM RF Module chaining configuration (Cont.)

Chaining Type

Configuration

Distancebetween

ESMB/C and

FXxA

Distancebetween

FXxA 1 and

FXxA 2

Distancebetween

FXxA 2 and

FXxA 3

Single chain of

two RF Modules

2/2/2@60 W to

6/6/6@20 W

upto 10 km upto 3.0 km

Two chains of

three RF Modules


Two chains of two

RF Modules

1/1/1/1/1/1@60 W to

6/6/6/6/6/6@10 W


Three chains of

two RF Modules


5.12.2 GSM - RRH chaining

The following are the supported GSM RRH (FHxx) chaining configurations:

Table 15 GSM RRH chaining configuration

Chaining Type

Configuration

Distancebetween

ESMB/C and

FHxA

Distancebetween

FHxA 1 and

FHxA 2

Distancebetween

FHxA 2 and

FHxA 3

Single chain of

three RRHs

2/2/2@40 W to

6/6/[email protected] W


Single chain of

two RRHs

2/2@40 W to 6/[email protected]

W


Two chains of

three RRHs

2/2/2/2/2/2@40 W to

6/6/6/6/6/[email protected] W


Two chains of two

RRHs

2/2/2/2@40 W to

6/6/6/[email protected] W


Three chains of

two RRHs

2/2/2/2/2/2@40 W to



Six RRH distance

between System

Module and RRH

upto 10 km and

RRH to RRH 1 km

(two chains)

2/2/2/2/2/2@40 W to




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Table 15 GSM RRH chaining configuration (Cont.)

Chaining Type

Configuration

Distancebetween

ESMB/C and

FHxA

Distancebetween

FHxA 1 and

FHxA 2

Distancebetween

FHxA 2 and

FHxA 3

Six RRH distance

between System

Module and RRH

upto 10 km and

RRH to RRH 3.0

km (two chains)

2/2/2/2/2/2@40 W to


upto 10 km 3.0 km 3.0 km

5.12.3 Common BCCH chainingThe following are the supported common BCCH chaining configurations:

Table 16 Common BCCH chaining configuration

Chaining

Type

Configuratio

n

FXxx 1/

FHxx 1

Distance

between

ESMB/C and

FXxx/FHxx

FXxx 2/

FHxx 2

Distance

between

FXxx 1/ FHxx

1 and FXxx

2/ FHxx 2

FXxx 3/

FHxx 3

Distance

between

FXxx 2/ FHxx

2 and FXxx

3/ FHxx 3

Single chainof three RF

Modules

FXCA/ FXDA:1+1+1@60 W

to 3+3+3@20

W

FXEA/ FXFA:

2+2+2@60 W

to 6+6+6@20

W for

FXCA/FXDA

upto 300 m FXEA/FXFA

2 m FXEA/FXFA

2 m

Single chain

of three RF

Modules

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m FXEA/

FXFA

2 m

Single chain

of two RF

Modules

FXDA/ FXCA:

1+1+1@60 W

to 3+3+3@20

W

FXEA/ FXFA:

1+1+1@60 W

to 6+6+6@10

W for

FXCA/

FXDA

upto 300 m FXEA/

FXFA

2 m

Two chains of

three RF

Modules

3+3+3@60 W

to 9+9+9@20

W

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m FXCA/

FXDA

2 m


94 DN09167685 Issue: 01F



Table 16 Common BCCH chaining configuration (Cont.)

ChainingType

Configuration

FXxx 1/FHxx 1

Distancebetween

ESMB/C and

FXxx/FHxx

FXxx 2/FHxx 2

Distancebetween

FXxx 1/ FHxx

1 and FXxx

2/ FHxx 2

FXxx 3/FHxx 3

Distancebetween

FXxx 2/ FHxx

2 and FXxx

3/ FHxx 3

3+3+3@60 W

to 9+9+9@20

W

FXEA/

FXFA

upto 300 m FXEA/

FXFA

2 m FXEA/

FXFA

2 m

Two chains of

two RF

Modules

2+2+2@60 W

to 6+6+6@20

W

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m 1 km

2+2+2@60 W

to 6+6+6@20

W

FXEA/

FXFA

upto 300 m FXEA/

FXFA

2 m 3.0 km

Three chains

of two RF

Modules

2+2+2@60 W

to 6+6+6@20

W

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m

2+2+2@60 W

to 6+6+6@20

W

FXEA/

FXFA

upto 300 m FXEA/

FXFA

2 m

2+2+2@60 Wto 6+6+6@20

W

FXEA/FXFA

upto 300 m FXEA/FXFA

2 m

Three chains

of two RF

Modules

2+2+2@60 W

to 6+6+6@20

W

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m

2+2+2@60 W

to 6+6+6@20

W

FXCA/

FXDA

upto 300 m FXCA/

FXDA

2 m

2+2+2@60 W

to 6+6+6@20W

FXEA/

FXFA

upto 300 m FXEA/

FXFA

2 m

Single chain

of three

RRHs

FHDA: 2 omni

40 W

FHEA: 12

omni 13.3 W

FHDA upto 300 m FHEA 2 m FHEA 2 m

Single chain

of three

RRHs

FHDA upto 300 m FHDA 2 m FHEA 2 m


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Table 16 Common BCCH chaining configuration (Cont.)

ChainingType

Configuration

FXxx 1/FHxx 1

Distancebetween

ESMB/C and

FXxx/FHxx

FXxx 2/FHxx 2

Distancebetween

FXxx 1/ FHxx

1 and FXxx

2/ FHxx 2

FXxx 3/FHxx 3

Distancebetween

FXxx 2/ FHxx

2 and FXxx

3/ FHxx 3

Single chain

of two RRHs

FHDA upto 300 m FHEA 2 m

Two chains of

three RRHs

FHDA upto 300 m FHDA 2 m FHDA 2 m

FHEA upto 300 m FHEA 2 m FHEA 2 m

5.12.4 RF Module - RRH chaining

The following are the supported GSM RF Module - RRH chaining configurations:

Table 17 RF Module and RRH chaining configuration

Chaining

Type

Configuratio

n

FXxx 1/

FHxx 1

Distance

between

ESMB/C and

FXxx 1/ FHxx

1

FXxx 2/

FHxx 2

Distance

between

FXxx 1/ FHxx

1 and FXxx

2/ FHxx 2

FXxx 3/

FHxx 3

Distance

between

FXxx 2/ FHxx

2 and FXxx

3/ FHxx 3

Three RRH in

one chain and

one RF

Module

RRH:

2+2+2@40 W

to

[email protected]

W

FHxA upto 10000 m FHxA upto 1400 m FHxA upto 1400 m

RF Module:

1+1+1@60 W

to 6+6+6@10

W

FXDA/

FXEA

upto 10000 m 2 m

Four sector

configuration

FXxA upto 10000 m FHxA upto 1400 m FHxA upto 1400 m

FHDA/

FHEA

upto 10000 m

Three RRHs

in one chain

and two RF

Modules in

one chain

FXDA/

FXEA

upto 10000 m FXDA/

FXEA

upto 1400 m



96 DN09167685 Issue: 01F



Table 17 RF Module and RRH chaining configuration (Cont.)

ChainingType

Configuration

FXxx 1/FHxx 1

Distancebetween

ESMB/C and

FXxx 1/ FHxx

1

FXxx 2/FHxx 2

Distancebetween

FXxx 1/ FHxx

1 and FXxx

2/ FHxx 2

FXxx 3/FHxx 3

Distancebetween

FXxx 2/ FHxx

2 and FXxx

3/ FHxx 3

Three RRHs

in one chain

and three RF

Modules in

one chain

FXDA/

FXEA

upto 10000 m FXDA/

FXEA

upto 1400 m FXDA/

FXEA

upto 1400 m


5.12.5 Examples of chained configurationsFor cabling instructions, see Creating stack, wall, and pole configurations for Flexi

Multiradio BTS GSM/EDGE , Creating FCIA configurations for Flexi Multiradio BTS

GSM/EDGE , and Creating FCOA Configurations for Flexi Multiradio BTS GSM/EDGE

documents.

The examples of chained configurations are as follows:

One chain of three RF Modules

Figure 30 Single chain of three RF Modules

ESMB/CUp to 10 km

Fxxx 1Up to 3 km Up to 3 km

Fxxx 1Fxxx 1

Three chains of two RF Modules

Figure 31 Three chains of two RF Modules

ESMB/C

U p

t o 1 0 k m

Fxxx 1Up to 3 km

Fxxx 1

Fxxx 1

Fxxx 2

Fxxx 2

Fxxx 2

U p t o 1 0 k m

Up to 10 km

Up to 3 km

Up to 3 km

Three chains of two RRH


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Figure 32 Three chains of two RRH

ESMB/C

u p t o 1 0

k m

u p t o 1 0 k m

up to 3 kmFHxx 1800XFHxx 900X


up to 10 km


Six RRH distance between System Module and RRH upto 10 km and RRH to RRH

3.0 km (two chains)

Figure 33 Six RRH distance between System Module and RRH upto 10 km and RRHto RRH 3.0 km (two chains)

ESMB/C

u p t o

1 0 k m

u p t o 1 0 k m

FHxx 900/1800Hup to 3 km

FHxx 900/1800H3 km

FHxx 900/1800H


FHxx 900/1800H3 km

FHxx 900/1800H

Three chains of two RF Modules in common BCCH

Figure 34 Three chains of two RF Modules in common BCCH

ESMB/C

Fxxx 900

u p t o

3 0 0 m

u p t o 3 0 0 m

upto 300 m

2 mFxxx 1800

Fxxx 9002 m

Fxxx 1800

Fxxx 9002 m

Fxxx 1800

Three RRHs in one chain and three RF Modules in one chain


98 DN09167685 Issue: 01F



Figure 35 Three RRHs in once chain and three RF Modules in one chain

ESMB/C

u p t o

1 0 k m

u p t o 1 0 k m



FHxx 900/1800H

FXxx 900/1800Hup to 3 km

FXxx 900/1800Hup to 3 km

FXxx 900/1800H

5.13 BSS21507 Flexible MCPA TX Power Pooling

The Flexi BTS RF Module (FXxx) has three branches which are equipped with the Multi

Carrier Power Amplifier (MCPA). Each MCPA can include up to 6 TRXs by keeping theTX power capacity of same module. An MCPA simultaneously amplifies all the

connected TRXs that provides enhanced coverage. MCPA power is 60 W and supports

shared RF configuration feature. Thus it can be dedicated to GSM/EDGE or shared with

other radio technologies(3G/LTE).

In static allocation, MCPA’s total output power is shared equally among all carriers

defined in that branch and hence the maximum TX power per TRX reduces when the

number of TRXs increases. This means that higher configurations have smaller cell size

and reduced coverage.

The Flexible MCPA TX Power Pooling feature divides the MCPA power flexibly between

different TRXs instead of fixed splitting. High output power is allocated to those mobile

stations that require it and lower power is allocated to those that can operate with low TXpower. This feature is controlled by a capacity-based licence key.

g If earlier RG301555 feature is used and taken BSS21507 in to use, license is required.

Figure 36 Coverage without and with flexible MCPA

15W coverage

MS Only 1 mobilecan be servedPL=0

BTSBTS

MS

MS

MS

a) Coverage without flexible MCPA

MS PL=0

MS

PL=1

MS

PL=1

MS

PL=0BTS20W coverage

all 4 mobilescan be served

b) Coverage with flexible MCPA


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With fixed MCPA (as shown in figure a), TX power is equally distributed among all the

TRXs (for example 15W). However, mobile stations at extended coverage area require

higher power (for example 20W). Since TRXs have a limited power of 15W, it is not

possible to serve mobile stations outside the 15W coverage area. PL=0 refers to the

TRX with maximum obtained power level.

With flexible MCPA (as shown in figure b), TX power is flexibly distributed among the

TRXs. The power is distributed according to the need and thus it is possible to serve

mobile stations outside the 15W coverage area. PL=0 refers to the TRX with maximum

obtained power level and PL=1 refers to the TRX with power level of 2dB attenuation.

Cell coverage depends on the number of the TRXs in the MCPA. When more TRXs are

configured it causes a reduction in cell size because the power is shared between all

TRXs. With the Flexible MCPA TX power pooling feature, it is possible to configure

dynamic power for the BTS.

Figure 37 Power allocation without Flexible MCPA TX Power Pooling

Fixed 60W MCPA TX power

Unused capacity

Idle

Occupied

Even if the call is in the bad RX field,TX power cannot be increased, as the restof the power is reserved for idle channels.

15W15W 15W 15W15W15WBCCH TRX 15W

15W15W 15W 15W 15WTRX 2PMAX=15W

15W15W15W 9.5W 15W6W 1.5WTRX 3PMAX=15W

6W 8W 15W 2.5W 8WTRX 4PMAX=15W

Used TX power

Unused TX power

15W 6W 47.5W 60W 36W 19W 45W 53W

7W15W41W24W0W12.5W54W45W

Maximum capacity used

TS 0 TS 1 TS 2 TS 3 TS 4 TS 5 TS 6 TS 7

The above figure shows an example of power allocation situation with 4 TRX

configurations. In this, the power is split in a fixed manner between different TRXs. The

MS in TRX3, TSL0 needs a higher TX power. It is not possible to increase the power of

TRX 3, TSL0 by using the 30W idle power since the power is allocated for the TRX 2,

TSL 0 and TRX 4, TSL0. These TSLs are idle do not use the power resulting in the

remaining 30 W power being unused.

With Flexible MCPA TX Power Pooling feature, the unused extra TX power capacity in

fixed TX power sharing is taken into use to increase the Flexi Multiradio BTS maximum

TX power per TRX. This unused TX power is considered as virtual TX power. The

practical amount of the virtual TX power depends on the number of TRXs in the BTS.

This virtual TX power can be then used to increase the BTS TX power.


100 DN09167685 Issue: 01F



Figure 38 Power allocation with Flexible MCPA TX Power Pooling

12W 20W 20W 20W20WBCCH SD/8 20W

20W20W20W 20W20W

20W 20W20W 20W 20W20W 12W

20W8W 8W8W 8W

BCCH TRX 20W

TRX2 PMAX=20W

TRX3 PMAX=20W

TRX4 PMAX=20W

BCCH TRX can be configured for higher output power and rest of the TRXs usedynamically high power only when it isneeded. This increases cell coverage.

BCCH TSL 2dB power reductionand compression possible whenBSS20985 is active.

Channel allocation and admission

control in BSC takes care of optimalchannel allocation.

Power compression in BTS 2dBpower reduction possible for higher power users.Pooled 60W

Maximum TX power

Idle

Occupied

The above figure shows an example of power allocation situation with 4 TRX MCPA

configuration. With 4 TRX MCPA configuration the TX power can be set to, for example,

20 W instead of 15 W. The Flexible MCPA TX power pooling feature then takes care that

60W power for those four TRXs is not exceeded. If a new call is needed on TRX4 in slot

2, the BTS can compress the TX power of TRX2 and TRX3 by 2dB in slot 2 using DTX

(Discontinuous Transmission). This results in compression of power from 20 W to 12.5 W

for both TRX 2 and TRX 3. The combined TX power for these two TRXs is now 25 W,

leaving up to 15 W of power for a new call on TRX4 slot 2.

The allowed BCCH TRX power classes when the MCPA power budget is 60 W and

Flexible MCPA TX Power Pooling feature in use are given below:

Table 18 TRX power classes limit for MCPA power budget 60 W

MCPA TRX configuration

Power classes in watts

1 TRX 60, 30, 20, 15, 10

2 TRXs 30, 20, 15, 10

3 TRXs 30, 20, 15, 10

4 TRXs 20, 15, 10

5 TRXs 20, 15, 10

6 TRXs 20, 15, 10

The allowed BCCH TRX power classes when 60 W MCPA is shared with other radio

technologies and for the GSM dedicated 52 W is given below. The remaining 8 W is

used by other radio technologies, 3G or LTE.


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Issue: 01F DN09167685 101



Table 19 TRX power classes limit for MCPA power budget 60 W and GSM 52 W



1 TRX 52, 30, 20, 15, 12.5, 10

2 TRXs 20, 15, 12.5, 10

3 TRXs 20, 15, 12.5, 10

4 TRXs 20, 15, 12.5, 10

5 TRXs 20, 15, 12.5, 10

The allowed BCCH TRX power classes when 60 W MCPA is shared with other radio

technologies, and for the GSM dedicated 40 W is given below.

Table 20 TRX power classes limit for MCPA power budget 60 W and GSM 40W



1 TRX 40, 30, 20, 15, 12.5, 10

2 TRXs 20, 15, 12.5, 10

3 TRXs 20, 15, 12.5, 10

4 TRXs 15, 12.5, 10

5 TRXs 12.5, 10

Supported configurations with RF Module (FXxx)

Table 21 Configurations supporting RFM

Configuration

Tx Power

AntennaOptimized

Number of

Number of Modules

Number of Antennas

3+3+3 30 W No 1 1 6

5+5+5 20 W No 1 1 6

6+6+6 20 W No 1 1 6

10+10+10 20 W Yes 2 2 6/12

12+12+12 20 W Yes 2 2 6/12


102 DN09167685 Issue: 01F



Supported configurations with RRH (FHxx) and Radio Module (RM)

Table 22 Configurations supporting RRH

Single Pipe

Two pipes

TRXs

Tx Power of

RM

Tx Power of

RRH

TRXs

Tx Power of

RM

Tx power of

RRH

3 30 W 20 W 6 30 W 20 W

4 20 W 13.3 W 8 20 W 13.3 W

5 15 W/ 20 W 10 W/ 13.3 W 10 15 W 10 W/ 13.3 W

6 15 W/ 20W 10 W/ 13.3 W 12 15 W 10 W/ 13.3 W

g RRH power pooling is not supported when the RRH is shared.

g When Flexible MCPA TX Power Pooling Feature is activated along with (Super)

Extended Cell downlink power compression on timeslots on the E-TRXs may reduce

the coverage of the extended region causing unexpected call drop(s) or disturbance.

Benefits

The Flexible MCPA TX Power Pooling feature provides the following benefits to

operators:

• It allows the operators to utilize the output power of the MCPAs optimally.

• It increases the capacity of the BTS for a given coverage area without the need

ofadditional Radio Frequency (RF) modules and also helps in network planning.

• It reduces the call drop rate in coverage limited networks.

• It enables the user to enhance coverage and capacity at the same time. It also

enhances the coverage or capacity individually which results in flexibility.

5.14 RG301743: Adjustable UL RLT Increase StepCurrently in the drop call process, the radio link time out process decreases one step

when the base station cannot receive SACCH properly and increases two steps after it

starts receiving the SACCH properly. The radio link countdown decreases to zero if it

does not receive SACCH for some time.

This feature allows the operator to adjust the size of a single increase step from the

default +2 up to +10 for Uplink Radio Link timeout (RLT) counter that is calculated and

controlled by the BTS.

Configuring the UL RLT increase step to a bigger value increases the chances of

maintaining a call, and decreasing DCR (drop call rate) correspondingly. The counter

control is connection specific and based on the used radio codec.


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Issue: 01F DN09167685 103



The new SEG level BSC parameters, UL RLT increase step (URIS) for non-AMR calls,

AMR UL RLT increase step (AURIS) for AMR-FR and Wideband AMR calls, and AMR

HR UL RLT increase step (AHURIS) for AMR-HR calls are visible and modifiable at the

BSC when the feature state is ON. The feature is controlled with BSC ON/OFF type

license key.

5.15 BSS101623 Energy Efficient Coverage

The feature ‘BSS101623 Energy Efficient Coverage’ feature provides a new licence to

control the IDD functionality in Flexi Multiradio, Flexi Multiradio 10 and Flexi Compact

BTS site types. It enhances the system efficiency with two TX antennas per sector.

Benefits

• This feature exploits two TX antennas for LTE. For e.g., Two 3-sector radio modules

• This feature makes use of Intelligent Downlink Delay Diversity that allows the

coverage gain of 5..8 dB

• This feature enables Antenna Hopping that allows the coverage gain 2..4dB

5.16 RG301726 Uplink Min RX level Based Access

The RG301726: Uplink Min RX level Based Access feature aims to improve SDCCH

DCR KPIs (drop call ratio key performance indicators), by filtering out non-viable call

attempts in RACH phase. The amount of SDCCH drops is reduced by filtering out RACH

bursts received from MS on CCCH that have a lower RX level for uplink than given value

of RACH Drop RX Level Threshold parameter.

The RG301726: Uplink Min RX level Based Access feature also introduces the Resource

Access Measurement RACH DROP LOW UL RX LEVEL counter which counts the

filtered call attempts.

Figure 39 SDB deployed in one sector


104 DN09167685 Issue: 01F



5.17 RG301965 GPS 1PPS+TOD Sync Support

With the RG301965 GPS 1PPS+TOD Sync Support feature GSM/EDGE BTS collects

the BSS sync signal (1PPS+ToD) from the GPS Receiver device of the GSM/EDGE BTS

or from co-sited e-NodeB. When using the sync source from GPS Receiver, the status of

the GPS Receiver is monitored by the BTS and can be viewed at the Element Manager.

The world time is also provided, thus DFCA hopping mode interaction is possible.

g • Using the RG301965 feature requires a BCF capacity type of license.

• Every BTS Site that has the RG301965 feature configured and activated consumesone unit of license capacity.

Dependencies on other features

• BSS SynchronisationBSS Synchronisation means that all the BTS sites in the synchronisation area are

fixed to a single external clock source, and the connections in the different cells are

aligned and synchronised at the time division multiple access (TDMA) burst level. In

other words, the time slots in the radio interface are constantly aligned. This

enhances or enables some key features in the BSS system, such as Dynamic

Frequency and Channel Allocation (DFCA).

This feature is dependent on the following BSS Synchronisation related features:

– BSS11073: Recovery for BSS and Site Synchronisation

– BSS20371: BSS Synchronisation Recovery Improvement

•DFCADFCA can be used with this feature.

Benefits

This feature:

• eliminates the need of connecting LMUB to get Synch Input from GPS

• helps in Capital Expenditure (CAPEX) and Operating Expenditure (OPEX) reductionby reducing additional investment on LMU and GPS receiver

• provides enhanced overall network FER versus C/I performance.


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Issue: 01F DN09167685 105



6 Basic GSM operation

6.1 Static Power levels

Static TX power for a BTS object can be set from BSC by using the PMAX parameter.

Default PMAX value is 0 and it has a range of 0 to 30dB in steps of 2 dB. The PMAX

ranges should be used as follows:

• PMAX range 0…14 - should be used in all live sites to ensure that all TX power

related alarms remain functional.

• PMAX range 16…30 - should only be used in lab testing. Note that, for example, in

scenarios where TX power levels are low, VSWR alarms may not work.

g Dynamic power control on BSC can adjust the timeslot transmit power from Static level.

The dynamic Timeslot capability of the system work can work in the whole 30 dB range.

6.2 BSS21113 Increased dynamic SDCCH capacity

This feature is related to BSS7036 Dynamic SDCCH Allocation feature. When BSS21113

feature has been turned on at the BSC, the maximum number of SDCCH channels for

each TRX is increased from 16 to 24 or 32, depending on the type of the TRX. It is

increased to a maximum of 24 channels in BCCH TRXs and to a maximum of 32

channels in non-BCCH TRXs.

6.3 BSS20872 Robust AMR signaling

Robust AMR signaling is an application SW product and requires a valid licence in the

BSC. The SW product consists of four separate features:

1. FACCH and SACCH repetition for “repeated ACCH” capable mobiles on AMR TCH

2. FACCH repetition for legacy mobiles on AMR FR

3. FACCH repetition for legacy mobiles on AMR HR

4. FACCH Power Increment on AMR TCH

FACCH/SACCH repetition and FACCH Power Increment proposals are specifiedtogether as a single repeat/power increment function so that the BTS can optimize the

use of the power increment and repetition according to the BTS Tx power level, mobile

capability and channel (AMR FR, AMR HR) used.

The BSC's role is to provide parameters related to this feature to the BTS. The BSC

checks the mobile’s capability and sends parameters related to this feature to the BTS at

the beginning of a call (Channel Activation message). The BTS then uses the

commanded features according to the radio conditions. The BTS indicates the usage of

FACCH/SACCH repetition and soft combining of repeated blocks in the Measurement

Result message to the BSC. This information is used for monitoring of Robust AMR

signaling.

Basic GSM operation Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

106 DN09167685 Issue: 01F




With FACCH repetition, the time taken to get a command to a mobile increases, so

repetition should only be applied when needed. Uplink SACCH repetition reduces the

frequency of measurements from the mobile, so it should also be used only when

needed. Repetition of the same measurement reports also affects the averaging of

measurements and the reaction speed of handover and power control algorithm.

Repeated AMR SACCH and FACCH in 3GPP Release 6

With 3GPP Release 6 and onwards, mobiles and BTSs can ask for SACCH frames to be

repeated exactly on transmit so that the original frame and its repeat can be decoded

together using Incremental Redundancy (soft combining) type decoding, similar to the IR

defined for EDGE data. Similarly, transmit repeat and Incremental Redundancy on

decode can also be used with downlink FACCH frames.

This gives about a 4 dB improvement in the C/I needed to decode the SACCH and

FACCH so that these channels are as robust as the lowest rate AMR codecs.

BSS13 supports the 3GPP protocol for repeated SACCH and FACCH, and will use theIncremental Redundancy on the uplink SACCH when needed for good normal operation

of the control channels.

Repeated AMR FACCH for existing mobiles

For mobiles designed according to ‘old’ 3GPP releases (that is, releases up to and

including Release 5), 3GPP has enhanced the radio interface protocol so that the

downlink FACCH can be repeated, to give the mobile two chances to decode the FACCH

before each link timeout and retry of the protocol. This gives about a 2 dB improvement

in the C/I needed to decode the FACCH, so that this channel is more robust and the

dropped call rate in handovers is reduced.

BSS13 will use the repeated downlink FACCH when the mobile is indicating poor downlink quality by requesting a low-rate AMR CODEC.

The 2 dB improvement in the C/I is not enough for reliable operation with the very lowest

rate AMR/FR codecs, so Nokia also offers the FACCH Power Increment feature for the

existing mobiles.

FACCH Power Increment for existing mobiles

With this feature, for 3GPP Release 5 and earlier mobiles, the BTS Tx power for

(downlink) AMR FACCH bursts can be increased by 2 dB, up to the maximum power

capability of the TRX. The Power Increment is not used when transmitting on the BCCH

frequency.

This will give an improved C/I for FACCH so that the dropped call rate in handovers is

reduced, but without adding significant interference to other ongoing calls. Combining

this feature and the Repeated AMR FACCH for the existing mobiles, BSS13 offers up to

4 dB improvement in the C/I for FACCH decode, and a corresponding reduction in the

handover dropped call rate.

For more information on Robust AMR signaling, see BSS20872: Robust AMR Signalling

document.


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Issue: 01F DN09167685 107



6.4 BSS20588 TRAU bicasting in AMR FR/HR handover

AMR speech codec is a key voice codec in Nokia GSM/EDGE BSS. AMR

packing/unpacking is one of the most important system level capacity/quality tools of the

Nokia AMR system feature. AMR packing/unpacking uses intra-cell handovers in order

to change speech coding between AMR HR and AMR FR.

In order to reduce audio breaks during a handover, the BSC establishes a unidirectional

connection in the downlink towards the target channel (bicasting) before the handover.

For an AMR FR/FR (or AMR HR/HR) handover, bicasting means that TRAU frames

carrying 16k (or 8k) TRAU coming from the transcoder (TC) are transmitted by the BSC

simultaneously to the source and target channels in 16k (or 8k) format depending on the

channel rate.

This method, presented in the following figure, tries to ensure that valid speech frames

are being transmitted in the downlink over the air interface before the MS moves from

the source to the target channel.

Figure 40 TRAU bicasting in AMR FR/HR handover

TC

BSC

TC

BSC

TC

BSC

DL

With this approach, it is possible to reduce the potential for breaks in audio in the

downlink during a handover. TRAU bicasting in AMR FR/HR handover also enables toestablish a unidirectional connection in AMR FR/HR intra-BSC handovers. When this

feature is used, source and target BTSs and TC are all using 8 kbit/s TRAU frame format

for Abis and Ater transmissions during an AMR packing/unpacking handover. In practice,

this means that the 8 kbit/s TRAU frames are sub-multiplexed onto a 16 kbit/s Abis

channel of the BTS that is sending/receiving TCH/AFS radio frames.

6.5 Basic GSM features

Flexi BTS supports the following basic GSM channel combinations:

• Combined broadcast control channel (BCCH) including


108 DN09167685 Issue: 01F



– frequency correction channel (FCCH)

– synchronisation channel (SCH)

– common control channel (CCCH)

– standalone dedicated control channel (SDCCH/4) – slow associated control channel (SACCH/C)

– random access channel (RACH)

• Non-combined broadcast control channel (BCCH) including

– frequency correction channel (FCCH)

– synchronisation channel (SCH)

– common control channel (CCCH)

– random access channel (RACH)

• Standalone dedicated control channel (SDCCH) including

– Standalone dedicated control channel (SDCCH/8) – Slow associated control channel (SACCH/C)

• Full rate speech (TCH/FS, TCH/EFS, TCH/AFS) with

– Slow associated control channel (SACCH/T)

– Fast associated control channel (FACCH)

• Half rate speech (TCH/HS, TCH/AHS) with

– slow associated control channel (SACCH/T)

– fast associated control channel (FACCH)

• Full rate circuit-switched data (TCH/F24, TCH/F48, TCH/F96, TCH/F144) with

– slow associated control channel (SACCH/T)

– fast associated control channel (FACCH)

6.6 BSS6071 Enhanced Full Rate Codec

Enhanced Full Rate Codec (EFR) uses the existing GSM 900/1800 full rate channel

coding but provides a considerably better performance in all channel conditions.

Moreover, in good channel conditions, the codec ensures equal or better quality than

Adaptive Differential Pulse Code Modulation (ADPCM).The EFR can coexist with Half Rate (HR) or Full Rate (FR) 'dual codec'.

For more information on Enhanced Full Rate Codec (EFR), see BSS10004 and

BSS6071: Enhanced Speech Codecs: AMR and EFR document.

6.7 BTS2023 Downlink and uplink DTX

Discontinuous transmission (DTX) is a mechanism allowing the radio transmitter to be

switched off during speech pauses. This feature reduces the power consumption of the

transmitter, which is important for mobile phones, and decreases the overall interference

level on the radio channels affecting the capacity of the network.


Basic GSM operation

Issue: 01F DN09167685 109



The DTX function is supported both in downlink and uplink for the following speech

channels: TCH/FS, TCH/EFS, TCH/AFS, TCH/HS, and TCH/AHS.

6.8 BTS2503 Compressed Abis timeslot allocation

In traditional transmission solutions, some capacity is left unused, especially in the case

of BTSs with one TRX, because one radio interface time slot is always used for the

broadcast control channel (BCCH). The compressed Abis time slot allocation makes it

possible to use this capacity for TRX signaling. This slot can 'steal' the traffic channel

(TCH) transmission slot, which leaves capacity for six full rate TCHs or twelve half rate

TCHs for that TRX.

In environments where it is not necessary to use the full traffic capacity of a TRX,

compressed Abis time slot allocation offers an ideal solution for using the transmission

medium more efficiently. With this configuration, it is possible to fit 15 TRXs to one 2

Mbit/s PCM.

6.9 BTS2067 Fast Associated Control Channel(FACCH) Call Setup

With Fast Associated Control Channel (FACCH) Call Setup, it is possible to establish a

call without using a stand-alone dedicated control channel (SDCCH). A traffic channel

(TCH) is set to 'signaling only' and switched over to normal speech operation when

needed. FACCH Call Setup is for emergency calls only.

For more information on Fast Associated Control Channel (FACCH) Call Setup, seeBSC3015: FACCH Call Set-up document.

6.10 BSS7036 Dynamic SDCCH Allocation

Dynamic Stand-alone Dedicated Control Channel (SDCCH) Allocation allows the

SDCCH resources to be configured according to the actual SDCCH traffic situation of a

cell. When the BTS temporarily needs greater SDCCH capacity than normal, the BSC

configures the idle traffic channel (TCH) resources for SDCCH use. For an example of

this, see the figure below. A maximum of two additional SDCCH/8 can be configured.

When the SDCCH congestion situation is over, the extra SDCCH resources are

configured back to TCH resources. Dynamic SDCCH Allocation can be used with both

combined and non-combined Broadcast Control Channel (BCCH).

The BTS only needs to be configured to the minimum static SDCCH capacity sufficient to

handle the normal SDCCH traffic.


110 DN09167685 Issue: 01F



Figure 41 Dynamic SDCCH allocation

TCH(busy)

TCH TCH(busy)

TCH(busy)

SDCCH/8

BCCH SDCCH/8 TCH

(busy)

TCH

(busy)

TCH

(busy)

TCH

(IDLE)

TCH

(busy)

TCH

TRXwith static

SDCCH/8

New TRXconfiguration

with additionalSDCCH/8

SDCCH congestion triggersdynamic allocation of SDCCH for free FR RTSL

BCCH SDCCH/8 TCH(busy)

TCH(busy)

An extra SDCCH resource is allocated only when the existing SDCCH is fully loaded.

When the dynamic SDCCH radio resource is totally free again, it is immediately

reconfigured for TCH use. Thus, the maximum number of TCHs is always in use

depending on the actual need of the SDCCH resources at each moment.

Dynamic SDCCH Allocation benefits traffic cases in which signaling is the only

transmission to the network, for example Short Message Service (SMS) traffic and

location updates. In some special places, such as airports and stations, the location

updates can produce sudden short-term SDCCH congestion. With Dynamic SDCCH

Allocation, this can be handled without any need to configure extra permanent SDCCH

capacity.

6.11 BTS2024 Synthesized frequency hopping

Synthesized frequency hopping is available for configurations that have at least two

TRXs per sector. Synthesized frequency hopping enables all TRXs to changefrequencies in successive timeslots, so that the carriers can hop at many different

frequencies in quick succession. Both random and cyclic hopping can be used. The

maximum number of frequencies per BTS site is 64. The number of frequencies can be

greater than the number of TRXs.

Note that the BCCH carrier must remain at a fixed frequency and at a fixed power level

to enable the MS to measure the signal strength.

6.12 BTS2013 Baseband Frequency Hopping

In Flexi Multiradio BTS, the RF Modules are interconnected through a Gigabit EthernetL2 switch to facilitate baseband hopping. Both random and cyclic hopping can be used

for baseband hopping. The number of frequencies used in the baseband hopping

frequency hopping sequence is the same as the number of carriers in the sector.

Baseband hopping in shared RFMs is supported only with TRX IDs 1 to 18 and not with

IDs 19 to 36.

Baseband hopping is allowed for all BTS configurations except with over 150 m

multimode fiber used with Feederless Site configuration.


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6.13 BTS2037 Air interface measurement pre-

processingThe measurement results for the active channels may be averaged for the TRX. This

option is useful when 16 kbit/s signaling is used because it reduces the capacity needed

on the Abis link. The averaging period may be set to consist of 1 - 4 SACCH multiframes.

Both uplink and downlink measurements are averaged. As a result, the BSC receives a

measurement report once at the end of the averaging period rather than after every

SACCH multiframe.

6.14 BTS2012 BTS time base reference from PCM

The PCM clock is used as a reference when tuning the long-term accuracy of the BTS

internal clock. The requirement for the accuracy is 0.015 ppm in order to meet the GSM

requirement (0.05 ppm) for the clock signal accuracy in the Air interface.

6.15 BTS2133 Short Message Service (SMS) point-to-point

Nokia base station supports the short message service (point-to-point) for both mobile

originating and mobile terminating calls.

6.16 BTS2033 Short message cell broadcast

The short message service (cell broadcast) defined in the GSM recommendations is

supported.

6.17 BSS6025 Short Message Service Cell Broadcastwith Discontinuous Receiving (SMS-CB DRX)

SMS-CB DRX enables phase-2 Mobile Stations (MSs) to receive only the needed blocksof the CBCH (Cell Broadcast Channel). This decreases battery consumption.

The BSC has a user interface for SMS-CB (Short Message Services Cell Broadcast) and

it stores CB messages in the BSS. After the BTS initialisation, the BTS operates in non-

DRX (Discontinuous Receiving) mode until SMS-CB DRX is activated in the BSC. When

SMS-CB DRX is employed, the BTS starts transmitting Schedule Messages to the cell

area. A Schedule Message includes information about a number of immediately following

consecutive CB messages, planned for that cell. The time between two Schedule

Messages is called the Schedule Period. The Schedule Period is one minute (see the

figure below).


112 DN09167685 Issue: 01F



The MS starts operating in DRX mode after the power up when it has received the first

Schedule Message. If the MS does not receive a Schedule Message, it has to read at

least the first block of each CB message.

Figure 42 SMS-CB DRX Schedule Period

Sch CB

1

CB

2

CB

31 Sch Sch

60 s

.... ....

CB

1

In DRX mode, in the first block of the Schedule Message, the MS receives information

about

• How many CB messages there are

• In which slot they will be transmitted• Message identifiers (if there are fewer than 6 new messages)

If there are:

• No new CB messages in successive schedule periods, the MS ends up reading only

the first block in each Schedule Message.

• 1 to 5 new CB messages, the MS does not need to read other blocks in the

Schedule Message, but it still needs to read the new CB messages.

• More than 5 new CB messages, the MS has to read more than one block in the

Schedule Message plus all the new CB messages.

6.18 BSS6083 Mobile Station (MS) speed detection

The purpose of this feature is to determine the speed of the Mobile Stations (MSs) in

GSM networks so that the fast moving MSs can be directed to macro cells and the

slower moving MSs respectively to micro cells whenever configured so by the BSC.

Furthermore, BSC statistics also collects this information.

The benefit of this feature is that it decreases the number of handovers in a micro-cell

network and thus increases network capacity.

The BTS estimates the MS's speed by using the Crossing-rate algorithm. The algorithm

is based on a comparison between the signal levels obtained from each burst and their

averaged value over one SACCH multiframe. The algorithm counts the rate at which the

signal level crosses the averaged signal level. The crossing rate is relative to the MS's

speed. The BTS sends the measured MS-speed information to the BSC by including it in

the 'Meas_res' message. The MS-speed indication can vary between 0 and 254 km/h (0

– 159 mph) in 2-km (1.25-mile) steps. If measurement averaging is used, MS-speed

measurement results are also averaged (see the figure below).


Basic GSM operation

Issue: 01F DN09167685 113



Figure 43 MS speed detection used for handover decision

BSCBTS

BTS

Macro cell

Micro cell(s)

Fast MSs

Slow MSs

Meas_res

Crossing-rate algorithm

HOs

The handover-decision algorithm in the BSC takes into account the MS-speed results

sent by the BTS. Furthermore, the MS-speed based handover parameters (nx, px, upper

speed limit (USL) together with lower speed limit (LSL)) and the adjacent cell layer

definitions are also used with this feature.

The handover (HO) and power control (PC) algorithm determines the need for the

handover as follows:

• If px averaged MS-speed indications out of last nx averaged MS-speed indications

exceed the USL, the MS is considered as a fast moving MS and the call will be

handed over to a suitable upper-layer cell (macro cell) if any.• If px averaged MS-speed indications out of last nx averaged MS-speed indications

are lower than the LSL, the MS is considered as a slow moving MS and the call will

be handed over to a suitable lower-layer cell (micro cell) if any.

Layer information and the umbrella handover criteria are used as the target cell selection

criteria. This means that the RX level in the target cell has to exceed the umbrella

handover requirement HO_UMBRELLA_LEVEL defined for every adjacent cell.

g The algorithm does not work with frequency hopping.

6.19 BSS20093 A5/3 ciphering

The ciphering algorithm A5/3 is a strong block cipher and provides improved security

over air interface links when compared to A5/1 encryption. If the network capabilities are

sufficient, A5/3 encryption should be deployed for maximum privacy over the air

interface. Nevertheless, the A5/1 algorithm can be used as fallback solution.

For more information on A5/3 ciphering, see BSS20093: A5/3 ciphering document.


114 DN09167685 Issue: 01F



6.20 Multiple Operator BSS Configuration (MOBBS)

The Multiple Operator BSS (MOBSS) feature allows sharing of Radio Access Network

Elements, and their resources by different operators. From base station point of view this

means sharing of the same RF resources respectively antenna(s) by 2G cells of different

operators.

Sharing is done according to the following:

• SCF allows defining more than one logical sector for the same set of RF resources

respectively its related antennas

• 2G Flexi BTS Site Manager displays that an RF resource is shared by different

logical sectors

• The maximum number of logical sectors per RF resource is 3

• The logical sectors may have different power levels. This has to be captured in theSCF

• New TRX(s) and antennas can be defined and allocated to already configured

MOBSS configuration

g The frequencies of the multiple sectors used in a pipe should be non-overlapping.

Consider a case of two sectors, one RF hopping and one non-hopping whereby the

BCCH of the second sector is part of MA list of the first sector. Under such a condition,

there are cases where two Rx bursts are received on Air with the same frequency. In

this case, the TRX test may fail. If we compare to Flexi EDGE, there is one key

difference. AIR3 loop in Flexi EDGE is on carrier/sector basis. In Flexi Multiradio, AIR3

loop is on pipe basis. So, if these sectors are in the same pipe in Flexi Multiradio, AIR3

loop, and subsequently, TRX test may fail.

EDGE license, MOBSS Optimized Configurations

MOBSS or EDGE license optimized configurations are based on having 2 artificially split

sectors using the same Tx and Rx antennas. This can be built with SCF configuration

that has more than 1 sector sharing the same antennas; and it can be resolved when

TRX objects belonging to 2 different sectors are mapped to same antennas.

The following table lists the MOBBS optimized configurations supported with Flexi

Multiradio BTS:

Table 23 2 sectors using same pipes configurations

Sectors

imapped to

same

antennas

Tx power

Antenna

optimized

# of FR

pipes

# of SM

(FSM/ESM

x)

# of

Antenna

Preference1) (M/S)

1+1 30-30/40-20 No 1 1 1/2 S

2+2 15-15/20-10 No 1 1 1/2 M

3+1 15-15/10-30 No 1 1 1/2 S


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Issue: 01F DN09167685 115



Table 23 2 sectors using same pipes configurations (Cont.)

Sectorsimapped to

same

antennas

Tx power

Antennaoptimized

# of FRpipes

# of SM(FSM/ESM

x)

# of Antenna

Preference1) (M/S)

1+1+1 20-20-

20/30-15-15

No 1 1 1/2 M

2+1+1 10-20-

20/15-15-15

No 1 1 1/2 S

2+2+2 10-10-10 No 1 1 2/4 S

EDGElicense

optimized,

first digit

expresses

normal

TRXs and

second digit

EDGE

TRXs

3+1 EDGE

opt

15-15 No 1 1 2/4 M

5+1 EDGE

opt

10-10 No 1 1 3/6 M

7+1 EDGE

opt

15-15 Yes 2 1/41 1/2 S

4+2 EDGE

opt

10-10 No 1 1 1 S

6+2 EDGE

opt

15-15/20-10 Yes 2 1 2 S

1) Where M indicates mandatory and S indicates supported configurations.

It is possible to define more configurations with 2 or 3 pipes. MOBSS can support up to

maximum 3 operators on one pipe.

Restrictions

• EX4.1 onwards, it is recommended to apply all BCCHs of MOBSS that share one

antenna line to be assigned the same static power level PMAX at the BSC.

• This feature is not supported when the feature RG602124 Composite Multi Site

Transmission is in use.


116 DN09167685 Issue: 01F



6.21 BSS101411 Extended BCCH

The "BSS101411 Extended BCCH” feature allows the reduction of the number of SI2

quarter messages that are sent in a normal BCCH channel. When this feature is in use,

all the individual SI2 quarter messages are sent in an extended BCCH sub-channel

instead of the normal BCCH, increasing the static CCCH channel capacity in a cell.

When this feature is in use, it reduces the amount of SI2 quarter messages that are sent

to the mobile stations (MS) and increases the capacity of these messages. Reducing the

number of SI2 quarter messages reduces the time taken by the MS to read them. As a

result of this, when 3G/TD-SCDMA is deployed within the GSM/EDGE network, the MS

takes reduced time for handovers and location updates. This feature improves the KPIs

on GSM and 3G/TD-SCDMA interworking.

For more information on Extended BCCH, see BSS101411:Extended BCCH document.

6.22 BSS21538 Extended Common Control Channel(CCCH)

The “BSS21538 Extended CCCH” feature increases the CCCH channel capacity in the

cell. It may be used for alleviating CCCH paging and access grant capacity problems if

these appear in the network.

With this feature, the operator can define one, two, or three extended CCCH channels in

the BCCH TRX. The non-combined channel structure of a CCCH is meant for bigger

cells. This feature aims to introduce more non-combined CCCHs, thus extending therange of non-combined configurations that a cell can assume in compliance with GSM

specifications.

The Extended CCCH feature provides the following benefits:

• Faster SMS services

• The paging capacity is enhanced by increasing the number of CCCH channels in the

cell. The paging success rate is improved with large location areas

• Increased use of packet switched (PS) services is possible without being constrained

by the access grant channel (AGCH) capacity

• Due to the increased rate of success in paging, calls are established faster

• The revenue is improved with more established/served calls

6.23 BSS21445 Packet Abis Congestion reaction

The feature “BSS21445 Packet Abis Congestion reaction” introduces congestion control

procedures that control the packet transmission rate into Packet Abis network. This

feature detects and reacts to congestion and also monitors the bandwidth usage. Packet

Abis offers a fully shared dynamic bandwidth with an upper limit that can be configured.

Further, it also increases the optimization gain, and prevents violations of PSN SLA

agreements.


Basic GSM operation

Issue: 01F DN09167685 117



With this feature, the BTS detects congestion at the BCF level and informs the BSC.

Even though the BSC does not detect congestion by itself, it acts upon the congestion

detection message sent by the BTS. The goal of congestion control procedures is to

avoid the overload of intermediate nodes and networks between the BTS and BSC, and

to avoid exceeding congestion thresholds (set as a percentage of the agreed CIR) on the

Abis link.

Congestion reactions:

• PS Data and AMR CODEC Adaptation

• Handover

• Call Admission Control


This feature enables overbooking, increases the optimisation gain and prevents

violations of PSN SLA Agreements.

Requirements

This feature is support is provided with RG20(BSS) EP1

6.24 BTS Overload Control

Overload Control is a mechanism provided by the BTS to monitor the internal overload

and prevent overflow of internal buffers, which would otherwise lead to unidirectional or

bidirectional call muting during call setups or handovers (HOs). BSC supports this

mechanism for a better subscriber behavior and improved performance.

There are two threshold values monitored by the BTS. They separate three overload

levels and trigger certain behaviors on both BTS and BSC side:

• Level 0 (no overload)

• Level 1 (first overload threshold) - BSC starts avoiding non-urgent HOs

• Level 2 (second overload threshold) - BTS starts rejecting TCH channel activation

and Mode Modify requests. BSC continues avoiding non-urgent HOs and performs

an automatic retry for the rejected TCH channel activation requests

When the first threshold level is exceeded, the BTS informs the BSC about that, sending

a message. When the BSC receives the overload information message, it starts avoiding

non-urgent TCH handovers in the affected BCF, for example: AMR packing/unpacking,

OSC multiplexing, and other.

When the second overload threshold is exceeded, the BTS starts responding to TCH

channel activation requests with Channel Activation Negative Acknowledge message,

with "processor overload" cause code. The cause value is defined in the 3GPP

specification. The BTS also starts rejecting Mode Modify requests. The TCH activation

can be for a call setup or for a handover. The BSC continues avoiding non-urgent TCH

handovers as in level 1.

BSC handles the Negative Acknowledge for both Speech calls and Circuit-Switched

Data call setups. It starts a 5-second timer and resends the Channel Activation message

to the BTS once again after the timer expires. There is no retry for High-Speed Circuit-

Switched Data calls. When the timer is running, MS is waiting on SDCCH. The BSC

does not start SDCCH handovers for the MS. The TCH channel is kept allocated in the


118 DN09167685 Issue: 01F



BSC. If the BSC receives Negative Acknowledge also for the retry, then the call is

released. If TCH activation was done for a handover, then the handover attempt is

canceled and target TCH channel is released. High-Speed Circuit-Switched Data calls

are immediately released after receiving the first Negative Acknowledge.

BSC handles the negative acknowledgement with “processor overload” cause so that the

radio timeslot is not blocked even if there are many consecutive Negative Acknowledge

messages for the same radio timeslot.

When the internal overload drops below the second overload threshold, the BTS informs

the BSC immediately. The BTS stops rejecting requests. The BSC keeps avoiding non-

urgent handovers. If the internal overload drops below the first overload threshold the

BTS informs the BSC and all the overload control reactions are stopped.

The following counters can be negatively affected due to the BTS Overload Control

reactions:

• 0500308 / TCH ACT NACK• 001028 / TCH ACT FAIL

• 001081 / TCH ACT FAIL CALL

• 001083 / TCH ACT FAIL TARGET

Furthermore, delaying TCH activations affects the SDCCH holding time KPI. Cancelling

TCH handovers affects TCH handover success rate and call drop rate.

The overload control reactions typically remain active for short periods of time. Due to

this short duration, the counters and KPIs may only be slightly affected.

Three UTPFIL parameters control the BSC reactions:

• avoidance of non-urgent TCH HOs (default is ON)• retry of channel activations (default is ON)

• retry timer duration (default is 5 s)

The same information message is used between BTS and BSC for reporting, cancelling,

and acknowledging internal overload and backhaul congestion. Both types of impact are

independent on each other and can occur simultaneously or separately.

Backhaul congestion denotes a state where the backhaul transport network is congested

or close to congestion. In this case, packets can drop and traffic is affected.

Requirements

The BTS Overload Control is available from the following SW releases onwards:

• BTS: EX4.2 PP1.1, EX5 1.0.1 or Flexi Multiradio 10 BTS GF1.0

• BSC: S15 PP5.0-1 and S16 0.2.0

BTS Overload Control does not require any licenses.

The BTS Overload Control applies to Packet Abis over Ethernet, Packet Abis over TDM,

and Legacy Abis (also called “TDM Abis”). BTS and BSC actions are the same for all the

three Abis types.


Basic GSM operation

Issue: 01F DN09167685 119



6.25 RG301917 Triple RFM 3*80W in 1900 band

This feature introduces fixed full band duplex filter, 5-10% reduction in power

consumption compared to FXFA/B, integrated OVP in DC supply line, iBW as wide as

possible target, 35MHz BW in downlink and 60MHz uplink BW.

6.26 RG301703 FXEB support in BSS

RG301703 feature provides BSS support for FXEB RF Module. FXEB is a new 3-sector

RF Module with 3x80W o/p power at the antenna connector. The module requires 3HU.

It supports instantaneous 35MHz BW in TX, 60MHz in RX:

•

TX filter 35MHz stuf, RX full 75MHz• optimized for four GSM TRXs (six TRXs supported with lower o/p power and/or

narrower band)

• enabling 20 MHz BW LTE 1TX + 15 MHz for GSM the maximum of four carriers total

80 W (one module)

• enable 20 MHz BW LTE 2TX MIMO + 15 MHz (below LTE carrier) +15 MHz (above

LTE carrier) for GSM the maximum of eight carriers total 80 +80 W (two modules)

6.27 RG301704 5W Output Power Step size for Flexi

MultiradioPreviously o/p power step sizes did not allow a full flexibility in deployment. This feature

provides smaller granularity during configuration of the o/p power per TRX. Additional

power levels with flat 5W granularity: 1W, 5W, 25W, 35W, 40W, 45W, 50W, 55W. Unified

power levels (except 60W on RRH) can be used on both RRH and RFM.

6.28 RG301756 FXDB support in BSS

RG301756 feature provides BSS support for FXDB and RF Module. FXDB is a new 3-

sector RF Module with 3x80W o/p power at the antenna connector.

• IBW of 35MHz in TX and Rx for 900 band

• GSM configurations up to 6+6+6

• WCDMA configurations up to 4+4+4

• LTE configurations up 20MHz

• up to 10 MHz BW LTE 1TX + max 4 GSM carriers

• up to 20 MHz BW LTE 2TX MIMO + max 8 GSM (4+4) carriers


120 DN09167685 Issue: 01F



6.29 RG301844 BSS Support for High Power RRH

Remote Radio Heads(RRH) are among the most important cogs in the wheel of

Distributed Base Station topology. RRHs help operators to fine tune their network for

coverage and other operational issues. The major benefits provided by Nokia's RRH are:

• Reduced RF loss

• 2x2 MIMO and 2-way diversity

• higher efficiency

• Flexible location capability

Decentralization of the macro base station into separate pieces has allowed the major

components of these distributed base station topologiesto be considered as some of the

most important sub-segments of the wireless hardware infrastructure market. The

second generation RRH from Nokia is an essential, cost-optimized version to keep theRemote Radio Head profitable.

6.30 RG302087 Narrow LTE RF Bandwidth

The RG302087: Narrow LTE Carrier Bandwidth feature allows allocating GSM TRX in

freed lower and upper slice of LTE bandwidth in RF Sharing deployments.

The improvement is dedicated for 5, 10, 15, and 20 MHz carrier-to-carrier separation in

GSM/LTE refarming.

The RG302087: Narrow LTE Carrier Bandwidth feature use is controlled with ON/OFFlicense in the BSC. When the licence state is ON in the BSC and the feature state has

been delivered to BTS, the 2G BTS allows GSM carrier allocation inside LTE nominal

bandwidth (BW) in co-sited deployment, usually with RF sharing.


Basic GSM operation

Issue: 01F DN09167685 121



7 Transmission

7.1 Basic transmission

7.1.1 Abis Trunk Transmission for E1 (ETSI) interface

Up to four full rate (FR) or Enhanced Full Rate (EFR) speech channels, or up to eight

Half Rate (HR) speech channels, are multiplexed on a single 64 kbit/s PCM timeslot. It is

possible to create point-to-point star, multidrop chain or remote star transmission

connections between BSC and BTS sites. This flexibility ensures that all kinds of

transmission needs are fulfilled: traditional star configuration, economical multidrop

chains, and reliable multidrop loops are all possible.

Up to 12 TRXs are supported on a single 2 Mbit/s PCM line. See also BTS2503

Compressed Abis timeslot allocation.

Abis Trunk Transmission Allocation is implemented using the standard G.703 2 Mbit/s

PCM frame structure.

For more information, see Nokia BSS Transmission Configuration in BSC/TCSM Product

Documentation.


BSS30285 Activation of additional two E1/T1 interfaces

7.1.2 Abis Trunk Transmission Allocation for T1 (ANSI) Interface

Abis trunk is a single transmission channel between two points, either the BSC or the

BTS. Up to four full rate/enhanced full rate (FR/EFR), and eight with Half Rate (HR)

speech channels are multiplexed on a single 64 kbit/s PCM timeslot. It is possible to

create point-to-point star, multidrop chain or remote star transmission connections

between BSC and BTS sites. This flexibility ensures that all kinds of transmission needs

are fulfilled: traditional star configuration, economical multidrop chains, and reliable

multidrop loops are all possible.

Up to 10 TRXs are supported on a single 1.5 Mbit/s PCM line. See also BTS2503

Compressed Abis timeslot allocation. This feature is implemented using the standard

T1.403 PCM frame structure.

The BTS supports Extended Super Frame (ESF) and SF/D4 framing. The ESF supports

CRC-6 checks and 4 kbit/s data link for performance management.


BSS30285 Activation of additional two E1/T1 interfaces

Transmission Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

122 DN09167685 Issue: 01F









7.1.3 Abis Trunk Signaling

Radio Signaling Link is a logical link between the BSC and the BTS in Layer 2. The RSL

is identified by a functional address known as Service Access Point, SAPI=0. Radiosignaling links over the Abis interface are addressed to different units by Terminal

Endpoint Identifiers, TEI. The TEI values are fixed and correspond to the TRX-id. The

TEI management is not used.

One signaling channel is used for each transceiver (TRX) and one for each BTS base

control function (BCF). Alternative signaling speeds are available: 16 kbit/s, 32 kbit/s, or

64 kbit/s. The selection of the signaling speed is done in the commissioning phase on

BTS basis. The same selection is also done on the BSC site when channel configuration

is defined.

Normally, 16 kbit/s TRX signaling speed is recommended for the FR operation. 32 kbit/s

TRX signaling rate is recommended for the HR use.

7.1.4 Network Synchronisation

In normal network conditions, synchronisation information is carried by selected E1 or T1

paths from upper to lower hierarchical levels according to the synchronisation plan, from

the MSC down to the BTSs.

Flexi Multiradio BTS selects the E1 or T1 signal that has the highest priority from a group

of pre-selected digital paths as the active synchronisation signal. In case of FIQB/FIYB

PIU's PseudoWire Emulation (PWE)/PWE relay/Packet Abis over Ethernet/Packet Abis

over Ethernet relay will have ToP and 3 SyncE's ( SyncE (EIF1), Sync E (EIF2), SyncE

(EIF3) ). Among ToP, 3 SyncE's and 8 PseudoWires, only one source can be in the

priority list at a time. The operator can change the group of signals using the 2G FlexiBTS Site Manager application. Selection of a new signal is automatic in case of input

failure and input recovery.

In addition to using E1 or T1 signals for synchronisation, it is possible to synchronize with

an external clock signal, such as the LMU clock signal.

For Packet Abis over TDM mode and in case of FIQB/FIYB PIU, the following external

synchronization sources are available:

• E1/T1's

• Sync input, internal timing

• 2 MHz Clock

For Packet Abis over Ethernet mode, the following external synchronization sources are

available:

• E1/T1's

• Sync input, internal timing

• 2 MHz Clock

For Packet Abis over Ethernet mode, out of 8 E1/T1’s, only one can be in the priority list.

Network Synchronisation can be protected via PDH Loop Protection. See BSS30280

Abis loop protection for more details.


Transmission

Issue: 01F DN09167685 123



7.1.5 BSS9065 Transmission Operability

Flexi transmission equipment is measured with several counters:

• All equipment can be measured within 15-minute/24-hour periods. This

measurement gives a fixed set of counters, which are near-end G.826 signal quality

counters. These counters are:

– Total time

– Available time

– Errored seconds

– Severely errored seconds

– Background block errors

– Errored block

• In the PWE mode, the following packet based counters are also available: – Received Ethernet Packets

– Transmitted Ethernet Packets

– Ethernet Received Errored Packets

– Received PW packets in tunnel

– Transmitted PW packets in tunnel

– Packets not matching any PW*

– Number of PW packets lost

– Early Packets

– Late Packets

– Received PW packets with L bit set* – Delay Variation Average

– Delay Variation Minimum

– Delay Variation Maximum

– Counters marked with a * are not reported to the BSC or NetAct

• A certain set of Flexi transmission equipment can be defined. Flexi transmission

equipment refers either to the whole equipment or part of it (functional entity and

supervision block). It is also possible to define the counters that are collected from

the equipment. To do this, the topology of the transmission network must be known

so that the measurement subject can be chosen.

7.1.6 BSS21234 Support for BTS PWE Counters at BSC/NetAct

PseudoWire Emulation (PWE) provides the transparent transport of a TDM signal (E1 or

T1) via a packet switched network (IP/Ethernet/UDP). The existing set of transmission

alarms and counters was adapted to enable gathering performance data from BTS at

NetAct. This facilitates network performance analysis for troubleshooting and

optimazation of packet switced network.


124 DN09167685 Issue: 01F



7.2 Transmission solutions

7.2.1 PDH traffic routing

Cross-connections define how signals are routed from a transmission interface to

another transmission interface. They are the basic building blocks for creating the path

for transmitting the Abis capacity from the BSC to the Nokia BTS via interconnecting

nodes.

Note that the cross-connections are only available in TDM mode.

Cross-connection granularities

There are several types of cross-connections available, and each has a different

granularity. Granularity means the bit rate at which a cross-connection is made, that is,the number of bits connected into a specific direction in a cross-connection. In 2 Mbit/s

mode, the available granularities are:

• 8k (1 bit)

• 16k (2 bits)

• 32k (4 bits)

• 64k (all 8 bits in a time slot)

• n x 64k (where n = 1 - 31)

BSS21129 Grooming

The cross-connection feature of the transmission units makes traffic grooming possible.Flexi BTS is capable of grooming traffic at for example 8 kbit/s granularity, which enables

fully optimized and flexible use of the available transmission resources. This ensures that

the path used for transmitting Abis capacity can be used efficiently.

Note that the grooming is only available in TDM mode.


Network element

Software release

required

Flexi Multiradio 10BTS

Not supported

Flexi Compact BTS Not supported

Flexi Multiradio BTS EX5.1

Flexi EDGE BTS EX5.1


Transmission

Issue: 01F DN09167685 125



7.2.2 BSS30280 Abis loop protection

PDH loop protection is an efficient way to protect traffic in a transmission network such

as a base station subsystem (BSS). In a live telecommunications network it is importantto secure, in addition to the actual payload traffic, the network synchronisation and the

centralized network management during any period of abnormal circumstances.

For these reasons, PDH loop protection protects:

• payload traffic

• network synchronisation

• network management connections

A transmission loop formed with elements consists of a loop master and one or more

loop slaves. Usually the loop master is a transmission node, whereas the loop slaves

can be either transmission nodes, BTSs or a combination of both inside one loop.

The loop principle is that the transmitted signal is always sent in both directions, but the

received signal is selected from one direction only. The loop master sends pilot bits on

the basis of which the switching decision is made. Each individually protected slave

station needs one pilot bit.

Network synchronisation must also be ensured in a loop network, and it follows the loop

principle in a similar way. The synchronisation switching takes place independently from

the pilot bits by having master clock bit (MCB) and loop control bit (LCB).

Based on the configured priorities, each network element decides individually from which

direction the signal and the synchronisation will be received, and, thus, it does not

require any external or additional supervision for its decision.

Figure 44 Loop principle

Loopmaster

= Loop slave

Normal receive direction

Reverse receive direction

Pilot bitsPilot bits

Direction 1Direction 2

Transmissionnetwork


126 DN09167685 Issue: 01F



Nokia's way of implementing loop protection is ultimately secure, providing very fast

route switching that recovers the transmission connections instantly. loop protection is

embedded and thus very fast. The loop protection protects against failures, such as

cable-cuts, equipment failures, heavy rain and multipath fading, and against obstacles in

the line-of-sight, such as cranes and growing trees.

Compared to an unprotected wireless network, PDH loop protection increases site

availability at least tenfold and prevents end-of-chain availability degradation.

The protection functionality is compatible with the existing Nokia BSS transmission.

Flexi Multiradio BTS can only act as a slave node in a PDH Loop protected network.

Note that the loop protection is only available in TDM mode.

For more information refer to the PDH Loop Protection in GSM Networks document that

can be obtained upon request.


Network element

Software release

required

Flexi Multiradio 10BTS

Not supported

Flexi Compact BTS Not supported

Flexi Multiradio BTS EX5.1

Flexi EDGE BTS EX5.1

7.2.3 Redundant Abis Trunk

If a failure or a problem in the transmission connection occurs between the BSC and the

BTS sites, an alternative transmission route (redundancy) is desirable.

Two alternative strategies are available for redundancy:

• a duplicated point-to-point type connection

• a redundant multi-drop loop connection

g Flexi Multiradio 10 BTS is not supporting multidrop loop configuration.

These two alternatives provide solutions for different transmission needs: either the

traditional redundant point-to-point configuration or the economical multidrop loop

configuration.

Redundant Abis Trunk for E1 interface (ETSI) is implemented by using the standard

G.703 2 Mbit/s PCM frame structure.

Redundant Abis Trunk for T1 interface (ANSI) is implemented by using the standard

T1.403 1.5 Mbit/s PCM frame structure.

Note that the Redundant Abis Trunk is only available in TDM mode.

For more information, see Nokia BSS Transmission Configuration in BSC/TCSM Product

Documentation.


Transmission

Issue: 01F DN09167685 127



7.3 BSS10045 Dynamic Abis allocation

Dynamic Abis provides an efficient transport mechanism for GPRS and EGPRS to use

more than one 16 kbps sub channel on the Abis interface for each packet data channel

(PDCH) on the Air interface. The continuous areas of PCM timeslots on PCM links are

configured as Dynamic Abis pools (DAPs) to provide the needed capacity.

The logical TRX utilizing Dynamic Abis is associated with a DAP in addition to the

standard fixed traffic channel (TCH) area. Any packet data channel would be

continuously using a master PCU channel located on a fixed area. Depending on the

traffic load on each Air interface channel, more capacity would be allocated from the

DAP. See the table below for the number of 16 kbps DAP sub channels used with each

CS and MCS.

Table 26 Number of 16 kbps DAP sub channels used with each CS and MCS

CS/MCS

Number of DAP sub channels

CS1 0

CS2 1

CS3 1

CS4 1

MCS-1 0

MCS-2 1

MCS-3 1

MCS-4 1

MCS-5 1

MCS-6 2

MCS-7 3

MCS-8 4

MCS-9 4

The PCU controls the downlink and uplink slave allocation on a radio block basis. Any 20

ms period on Abis is controlled based on real traffic demand. Downlink and uplink

allocations are controlled separately. The slave allocation is informed to the BTS by in-

band signaling on the corresponding downlink master channel.

Multiple logical TRXs can share a DAP. Multiple DAPs can be configured for each BTSand for each physical Abis link.


128 DN09167685 Issue: 01F



7.4 BSS5850 Satellite Abis

Satellite Abis allows the use of satellite connections on the Abis interface between the

BSC and the BTS. Satellite Abis enables you to create network coverage in areas where

the coverage could not otherwise be implemented because of the limitation of the

transmission media. Typically, these remote BTSs are used in low-capacity and

temporary applications. The BTS software adapts to the satellite delay (max 280 ms in

one direction) and the BSC and BTS perform the necessary alignments. Note that

satellite Abis restricts the BTS performance in higher capacity activities on CS and PS

data. It is recommended to configure the BTS so that a non-combined BCCH configured

and a SDCCH/8 to the TCHs only TRX, whenever possible. It is also recommended to

configure PS data so that high coding schemes are used only in one timeslot or that low

coding schemes are used in multiple timeslots.

This feature is activated for each BSS individually. It is activated by an Abis_typeparameter switch in both the BSC and the BTS.

7.5 BSS21497 Enhanced satellite support

New IP-based satellite services with dynamic bandwidth allocation have delays up to 400

ms in one direction.

7.6 BSS21439 Packet Abis Sync. ToP IEEE1588v2

The feature “BSS21439 Packet Abis Sync. ToP IEEE1588v2” takes care of

synchronization of the traffic in BSS transmission using Packet Abis over Ethernet with

the transmission sub-modules FIYB and FIQB in the System Module (ESMB/C). Timing

over Packet (IEEE1588v2) is a transparent synchronization solution for packet-switched

networks, where a standardized protocol is employed to transparently synchronize the

base stations across Layer 2 or Layer 3 networks. The protocol utilized is IEEE1588v2

(also known as the Precision Timing Protocol (PTP)). The Timing over Packet (ToP)

server clock provides the synchronization information to the BTSs at the sites. The

integrated BTS capability (or ToP Slave Clock) recovers the clock signal from the Timing

over Packet data it receives.

Since no external equipment (GPS receiver) or E1 link is necessary for synchronization

at the BTS site, capital expenditure savings can be derived. Further, there is also the

possibility to employ a single timing server (Master) solution for both WCDMA and

GSM/EDGE networks. Operational expenditure savings result from the improved

bandwidth efficiency beyond that which is achievable with CESoPSN Adaptive Timing.

Furthermore, this solution is more robust to network impairments than Adaptive Timing,

thus lower quality packet-switched networks can be employed for the transport backhaul

solution.

Requirements

• BSC S15 EP1.2

• Flexi Multiradio BTS EX4.1


Transmission

Issue: 01F DN09167685 129



• For Flexi Multiradio 10 BTS, GF1 0.1.0 BTS software and S16.1 1.1.0 BSC software

is required

7.7 BSS21454 Packet Abis over Ethernet

The feature “BSS21454 Packet Abis over Ethernet” enables the transport of Abis

information using native IP over Ethernet networks. The Packet Abis solution removes

the traditional TDM Abis structure, where the static relationship between the Air and the

Abis interfaces is eliminated. This allows cellular network operators to migrate from the

traditional static TDM to PSN, in a more efficient and cost effective way than with already

available solutions adopting PWE3 Circuit Emulation Service over Packet Switched

Network (CESoPSN). For implementing this feature, a new functional unit, Exchange

Terminal for Packet Abis over Ethernet (ETPE) is introduced. This is a licensed feature.

Figure 45 Packet Abis over Ethernet

This feature provides following benefits:

• The feature provides a better solution than PWE in terms of delay, cost, usability,

performance, and operability

• Cost reduction due to simplified operation

• Support for the already identified transport enhancements, such as A interface over

IP, and paving the way for the future transport and telecom GSM/EDGE features

• Synergy savings by exploiting co-siting with other radio access technologies

(WCDMA, LTE) and sharing the same type of transport network

Requirements

• BSC S15 EP1.2

• Flexi Multiradio BTS EX4.1• For Flexi Multiradio 10 BTS, GF1 0.1.0 BTS software and S16.1 1.1.0 BSC software

is required

7.8 BSS21438 Packet Abis over Satellite

The feature BSS21438 “Packet Abis over Satellite” enables the possibility for Packet

Abis to be used across satellite links (either TDM or Ethernet based). Packet Abis over

Satellite is robust to the impairments introduced by traditional satellite links. A BCF is

interpreted to be Packet Abis over Satellite configured if its OMUSIG Dchannel RTO.init

parameter value is 800ms or higher. This feature "BSS21438 Packet Abis over satellite”is controlled by a TRX capacity based license key.


130 DN09167685 Issue: 01F



Packet Abis is a fully integrated solution, and provides the Abis optimization function.

This reduces the bandwidth requirements, and investment in additional external Abis

optimization equipment, resulting in significant capital and operational expenditure

savings.

Requirements

• BSC S15 EP1.2

• Flexi Multiradio BTS EX4.1


is required

7.9 BSS30450 Packet Abis Synchronous Ethernet

The feature “BSS30450 Packet Abis Synchronous Ethernet” provides a further synchronization option for Packet Abis over IP/Ethernet networking scenarios.

Synchronous Ethernet is an end-to-end synchronization solution for packet based

backhaul networks. It provides a frequency synchronization capability, but without time /

phase synchronization. The solution recovers the clock out of the continuous received

physical Ethernet signal edges. Further using proven PLL technology for cleaning the

clock from Jitter, prior to distribution of the clock information via egress Ethernet links.

Synchronous Ethernet provides a stable synchronization solution for Packet Switched

Networks which is not dependent upon the network loading or any other network

impairments. It provides OPEX savings since the realization is more efficient than Timing

over Packet (ToP) solutions. It is the only possible synchronization solution that does not

require an external synchronization source for Packet Radio links. Furthermore, SSM

(Synchronization Status Message) management is supported by the solution, which

enhances the synchronization overview and fault management across the overall

network for the operator.

Requirements

• The BSC3i 1000/2000 or Flexi BSC with supporting interface module is required

• The FIYB or FIQB Module is required for the Flexi EDGE (or Flexi Multiradio) BTS


is required

• The feature is supported with RG20(BSS) EP1

• The Packet Abis over IP/Ethernet Software and Licence Key are required

Operational Aspects

Note that in order to maximise the quality of the transmitted clock signal all intermediate

nodes (for example, in a BTS chain) should support the Synchronous Ethernet capability.

7.10 BSS21440 Packet Abis over TDM

This fully integrated feature enables the transport of Abis information using native IP over

Time Division Multiplexed (TDM) Networks.



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Issue: 01F DN09167685 131



The operator can utilise the existing installed TDM Infrastructure, easing the introduction

of the Packet Abis solution. As for Packet Abis over Ethernet, Packet Abis over TDM

also offers significant bandwidth savings in comparison with traditional TDM transport

since it introduces a very efficient and fully integrated Abis Optimization capability. The

integrated Abis Optimization also facilitates the introduction of high bandwidth features

such as EDGE Evolution and OSC without necessarily increasing the backhaul

bandwidth capacity requirement. Bandwidth can be shared by CS, PS and Signalling

traffic. There are no predefined limitations except the total available bandwidth provided

by the physical links. This can result in E1/T1 leased line and/or Microwave Radio

license savings.

Functional Description

The Packet Abis solution removes the traditional TDM Abis structure, where the static

relationship between the Air and Abis Interfaces is eliminated. Further, Abis Optimization

through the removal of silence and idle frames, multiplexing and bandwidth sharing for

the CS- and PS-Userplanes, Control-Plane and Management-Plane achieves significant

bandwidth savings. That is, if no data needs to be sent then no capacity is

occupied/utilised. The Packet Abis U-Plane is transported over UDP/IP/MLPPP and the

C-Plane/M-Plane is transported over SCTP/IP/MLPPP. The physical interface supported

is TDM. Multiple E1 or T1 interfaces effectively provide a 'virtual common bandwidth'

using MLPPP.

Packet Abis over TDM is supported by all existing FlexiEDGE BTS transport sub-

modules, including FIFA. For the FIYA and FIQA Modules the TDM Interfaces are utilised

- The FIYB and FIQB modules may also be utilised.

g This feature does not support Echo-Request and Echo-Reply.

Operational Aspects

The utilisation of Packet Abis (both Packet Abis over IP/Ethernet and Packet Abis over

TDM) requires a balancing of the signalling load in the BSC and therefore it is necessary

to employ feature BSS21335 Precise Paging. Furthermore, the Precise Paging feature

also provides a positive effect for the end user experience during network busy periods.

Furthermore, the feature (and licence key for) RG301720 IUA ISDN Q.921-User

Adaptation is required and must be activated before the Packet Abis feature is activated.

Requirements

• The features (and licence key for) BSS21323 L3 Connectivity for Flexi BSC product

family and BSS21335 Precise Paging are required. The feature (and licence key for)

RG301720 IUA ISDN Q.921-User Adaptation is also necessary. The BSC3i1000/2000 or Flexi BSC with ETP and a new version of ETS2 interface module are

required:

– The PCU2-D or PCU2-E is required. The PCUs utilised for Packet Abis should be

introduced into different tracks within a BCSU from those which are used for

Legacy Abis

– BSC3i 1000 (one cabinet): 2+2 ETP Modules

– BSC3i 2000 (two cabinets): 6+6 ETP Modules

– Flexi BSC: 6 + 6 ETP Modules

– With the ETP Module, the LAN switch extension for BSC3i 1000/2000 and Flexi

BSC with the latest LAN switch version (ESB24-D) is necessary


132 DN09167685 Issue: 01F



– When using the ETP Module with the BSC3i 1000/2000, the BCSU CPU memory

requirement is 1 GB (refer to Section 3.1) and not 512 MB that is possible for

other configuration scenarios

• The feature is supported with RG20(BSS) EP1• The FIEA, FIPA, FIFA, FIYA or FIQA Module is required for the Flexi EDGE (or Flexi

Multiradio) BTS. The FIYB and FIQB modules may also be utilised.


is required

7.11 BSS21271 Abis Delay Measurement (TDM, PWE3)

The feature “BSS21271 Abis Delay Measurement (TDM, PWE3)” provides the Abis

delay measurement for time division multiplexing (TDM) based networks or networks

utilizing integrated/standalone Pseudowire equipment solutions. The feature introduces anew BSC transmission measurement, "120 - TDM/PW Abis Delay Measurement" for

measuring the round trip time of data frames/packets. This measurement provides

performance measurement (PM) data about the transmission delay occurring in the Abis

interface. The feature is controlled by an ON/OFF type license key.

Figure 46 Round trip time/Abis delay measurement

This feature provides the benefit of improving the call success rate and EDGE

throughput by allowing operators to monitor the SLA levels of their TDM and PSN

backhaul leased lines released with Pseudowire solutions.

Requirements


GF1.0


• BSC BSC3i or Flexi BSC with BSC S15 SW


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Issue: 01F DN09167685 133



7.12 BSS30395 Packet Abis Delay Measurement

The feature “BSS30395 Packet Abis Delay Measurement” introduces a new transmission

measurement for measuring the two-way delay of data packets, that is, the bi-directional

round trip time (RTT). In addition to RTT values, the variation and sliding averages of

RTT are also measured. It provides packet delay performance measurement (PM) for

packet transport networks in the Abis interface that employ the features Packet Abis over

TDM or Packet Abis over IP/Ethernet. The feature is controlled by an ON/OFF type

license key.

Requirements

• BSC3i 1000/2000 or Flexi BSC with BSC S15 SW

• Flexi EDGE BTS EX4.0 or Flexi Multiradio BTS EX4.1 with FIQA, FIYA, FIQB, and

FIYB modules in case of PAoPSN and FIQA, FIYA, FIQB, FIYB, FIEA, FIPA, andFIFA modules in case of PAoTDM.

• NetAct OSS 5.2 CD Set 3

7.13 BSS21503 FlexiPacket Radio Connectivity

The feature “BSS21503 FlexiPacket Radio Connectivity” provides transmission support

for chain and spur networking applications, enabling a direct interfacing between Flexi-

Packet Radio and the Flexi EDGE BTS. FlexiPacket Radio (FPR) is the packet

microwave radio (MWR) of Nokia, which provides support without an indoor unit for

tail/chain sites in co-sited BTSs.

FPR runs independently and provides Ethernet connectivity towards Flexi EDGE BTS.

FPR support with Flexi BTS extends the scope of Nokia unique "Zero Footprint" solution

realized with the Flexi BTS platform.

This complete solution is fully outdoor compatible and supports wide range of

applications, consequently offering an ideal and optimized integrated site solution.

This feature provides the following benefits to operators:

• It can be applied to tail and chain sites without the need for an indoor unit (Flexi-

Packet Hub).

• Reduces the number of modules and interfaces by supporting direct interfacing

between the Flexi BTS and FlexiPacket Radio.• Reduces CAPEX as a result of minimized cabling and reduced hardware.

• Enhances MTBF for the complete solution with no interoperability issues.

• Simpler and more efficient installation, commissioning, maintenance processes, and

operations.

• Local commissioning and troubleshooting for FlexiPacket Radio links is possible

without any changes to cabling from BTS to MWR and without interrupting Abis

traffic.

• Reduces OPEX through the extension of the "Zero Footprint" capability to include the

transmission solution.

• Reduces total cost of MWR solution due to lesser number of active components

used, thus reducing the site power consumption.


134 DN09167685 Issue: 01F



Requirements

• BSC S15

• Flexi EDGE BTS EX4.0, Flexi Multiradio 10 BTS GF1.0 or Flexi Multiradio BTS EX

4.1 with FIQx/FIYx transmission sub-module

• NetAct OSS 5.2 CD Set 3

7.14 BSS101417 QoS Aware Ethernet Switching

The QoS Aware Ethernet Switching feature allows Ethernet switching based on traffic

priority and traffic shaping, which restricts the egress rate and ensures higher priority

traffic delivery over lower priority traffic. This feature ensures that high priority packets

are not getting dropped. QoS awareness also allows ingress policing.

g In Flexi EDGE and Flexi Multiradio BTS, QoS Aware Ethernet Switching feature is

supported both with PWE and PAoPSN (Packet Abis over Ethernet) operation modes.

In Flexi Multiradio 10 BTS and Flexi Compact, it is supported in PAoPSN mode.

This feature is controlled by a capacity-based license and the license control is provided

by the BSC. If the license for the feature is not enabled, the BTS sets a transmission

alarm.

The feature is configured at the BTS via SCF file and 2G Flexi BTS Site Manager.

Ethernet-traffic aggregation can be achieved from co-located BTS or even remote BTS

sites (daisy chaining), using BTS embedded functionality. The BTSs can be 2G, 3G, LTE

or other vendor’s BTS, or any other device using Ethernet media.

Aggregated Ethernet traffic is shaped according to different configurable levels such asavailable uplink capacity. This avoids any overload situation in case of bandwidth limited

backhaul connections.

Figure 47 QoS Aware Ethernet Switching

Eth

Eth

Eth

IntegratedEthernetswitch

Flexi

BTS

BTS*

Co-located BTSs

Uplink traffic Flexi BTS

Uplink traffic BTS

lowpriority

highpriority

lowpriority

highpriority

Ethernet shaping level(available uplink capacity)

lowpriority

highpriority

Aggregated uplink traffic

*BTS can be 2G, 3G, LTE or other vendor’s BTS, or any other device using Ethernet media.

Another base station can be connected to Flexi BTS either from the same location or

daisy chained from different locations.


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Issue: 01F DN09167685 135



Figure 48 Ethernet-based BTS daisy allocation with BTS integrated Ethernet switch

Integrated

Ethernetswitch

FlexiWCDMA BTS

BSC

RNCGateway

IP / EthernetEth

Eth

Eth

Eth

E1/T1

Flexi

2G BTS

External switch is needed

in controller site for 2G-3Gtraffic separation

Benefits

The QoS Aware Ethernet Switching feature provides the following benefits to the

operator:

• It allows the operators to aggregate traffic to a single Ethernet port or to shape the

network SLA without using additional site equipment.

• It allows common backhaul for different technologies (GSM/WCDMA/LTE).

• It provides Zero Footprint solution (direct connection from MWR to BTS without MWR

Indoor unit).

• It supports switching of Baby – Giants, Jumbo Frames that have MTU size > 1500

(16xx octets) in Ethernet ports.

7.15 BSS101459 Full GE Support in FIYB/FIQB

In case of a chain or ring topology or in case of co-siting, a Flexi EDGE or Flexi

Multiradio BTS GSM/EDGE with FIYB/FIQB has a chain/ring capacity to 100 Mbit/s with

FlexiPacket Radio solution (zero footprint MWR solution). Enabling Gigabit Ethernet

(GE) on the electrical interfaces increases the capacity to 1000 Mbit/s and enables a

cost-effective (no indoor unit) solution. In this case, the Fiber (GE optical) is terminatedat FIYB or FIQB in the Flexi EDGE or Flexi Multiradio BTS. The interconnection of the

BTSs is done using GE electrical interfaces. Without this feature, external equipment

would be required to increase the fiber ring capacity.


136 DN09167685 Issue: 01F



Figure 49 Optical and electrical GE connections

Figure 50 Optical and electrical GE connections with MWRs

7.16 BSS101414 Packet Abis Transport MediaConversion

With Packet Abis Transport Media Conversion feature, it is possible to connect Flexi BTS

using a Packet Abis over TDM link with a Flexi BSC using Packet Abis over Ethernet

link. The solution can also be employed in combination with the MultiController BSC

(mcBSC). Media conversion requires Packet Abis to be used in both BSC (Packet Abis

over Ethernet) and BTS (Packet Abis over TDM).

Figure 51 Packet Abis Transport Media Conversion

TDM PSNETH

Media

Conversion

TDM

Flexi BTS

mcBSC

or

Flexi BSC


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Issue: 01F DN09167685 137



With this feature, BTS and BSC can be connected via crossed media access. Packet

Abis Transport Media Conversion feature has no license. The feature can be taken into

use by installing an external third-party media conversion device (router) to the Abis.

The Packet Abis Transport Media conversion device is positioned at an aggregation Sitelocation. The media conversion device can be located near BTS sites and the existing

TDM-based transmission network can be used at the last mile of Abis. Aggregation and

QoS aware scheduling of the Packet Abis traffic are performed at the IP layer.

By using this feature, BSC connectivity for BTSs with Packet Abis over TDM is enabled

with Ethernet interfaces supported by the BSC. The used device needs to:

• Terminate Packet Abis over TDM

• Aggregate and schedule Packet Abis Traffic at IP layer meeting the QoS

• Terminate Packet Abis over Ethernet

Benefits

The Packet Abis Transport Media Conversion feature protects the existing PDH device

investment for operators, whilst enabling a smooth backhaul evolution (from PDH to

IP/Ethernet), in particular for Microwave Radio first mile applications.

Requirements

• Multicontroller BSC support is provided with RG20(BSS)

• The BSC3i 1000/2000 or Flexi BSC with supporting interface module is required

• Support is provided with RG20(BSS) EP2

• The Packet Abis software and Licence key is required

7.17 Functional description

In an existing implementation, antennas within a BTS are controlled by same power and

were co-located. This caused higher rates of inter cell handover possibilities.

Figure 52 Without Composite Multi Site Transmission feature

Cell 7

Cell 6

Cell 5

Cell 4

Cell 3

Cell 2

Cell 1

HO

HO

HO

HO

HO

HO


138 DN09167685 Issue: 01F



In Composite Multi Site Transmission feature, antennas at different locations are merged

into one single logical cell, which helps in reducing the inter-cell handover. The user is

able to travel from one node to another inside the logical cell without a handover. Inter-

cell handover is needed only when moving from one logical cell to another. When a

handover occurs inside a logical cell, the TRX id and TSL remains the same but the

composite node id changes. In a composite cell, the BTS simultaneously uses one node

for transceiving and one node for receiving.

Figure 53 With Composite Multi Site Transmission feature

Composite Multi Site Transmission feature supports both Multi floor and High Speed

Railway solution where handovers occur frequently. In both the cases, this feature

reduces the inter-cell handovers and thereby improves the network performance.

For call set up and handovers, BTS informs the BSC about the nodes with the help of the

two messages, Channel Required and Measurement Result.

• Channel Required

For requesting a channel in call set up, BTS provides transceiving node id, receiving

node id and Timing Advance for the BSC in the Channel Required message.

• Measurement Result

For handover, BTS provides Doppler frequency, transceiving node id, receiving node

id and Timing Advance for BSC in the Measurement Result message.

BSC provides the details received through these messages back to BTS in Channel

Activation message for relaying them to target cell BTS in call setup and in BSC internal

handovers when the feature is enabled. BSC chooses any one of the two messages sent

by the BTS, depending upon the scenario.

• Call setup

For SDCCH channel, Channel Activation, BSC takes the details from Channel

Required message. For TCH channel, Channel Activation BSC takes the details

either from Channel Required or, from the latest Measurement Result message.

• BSC internal handover


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For internal handovers, the BSC takes the information from the latest Measurement

Result message that is received in source cell. If the BSC does not receive any

measurement result on a source channel before starting a handover, it sends the

latest composite cell information received from the BTS.

BTS uses this information for correct mobility management inside composite cell.

BSC calculates the maximum allowed DL power level for a transceiving composite cell

node from each Measurement Result message. The Maximum DL power level is the

sum of Maximum Tx power of current composite node and the BSs Tx Pwr Max/BS Tx

Pwr Max 1x00. BSC uses this maximum DL power level in handover and power control

algorithms.

The user can control RACH threshold of each individual composite cell node separately,

which allows more flexible MS mobility management.

Tracking of node id by PCU and BTS

For the GPRS and the EGPRS connections the BTS cannot use the same tracking

mechanism that it uses for the CS calls because PS connections allow multiplexing of

multiple MSs in the same radio resources. In other words, this means that the BTS does

not know for which MS the downlink radio block scheduled by PCU is addressed, and

therefore, it does not know the correct transceiver antenna to be used for transmitting. To

avoid this problem, one solution is to transmit through all the antennas, that is

broadcasting, but that might cause too much interference and degrade the radio link

quality.

To avoid the need for broadcasting, the BTS monitors MS’ location through the different

nodes and informs the PCU about which transceiver node the MS has used to transmit

the latest radio block. The BTS includes the latest node information of the MS into all the

uplink frames it forwards to the PCU and the PCU keeps records of that nodeinformation. When the PCU is addressing the downlink frame to certain MS, it includes

the MS’ node information to the downlink frame to inform the BTS about which antenna

the data might be transmitted from. If the PCU does not have the node information

available or if the downlink block is addressed to all the MSs multiplexed in the same

resources, then it informs the BTS to broadcast the downlink frame via all the antennas

configured in the Composite Multi Site Cell.

Node id field in PCU frames

In uplink data frames, there are new three bit field to indicate node id. Values from one to

six indicates node id. Values zero and seven are as reserved values on uplink. For

downlink data frames, there are two new three bit fields to indicate node ids. First node

id is used to indicate node id of downlink frame content and the second node id is usedto indicate the node id of USF. Values from one to six indicates node id. Value zero

indicates no transmission and seven indicates transmission from all nodes.

7.18 RG301994 Longer Sync Cable between FSMx &ESMx

In case of collocated GSM and WCDMA sites with MR BTS, when RF Sharing is done, a

sync cable is required to connect the 2G and 3G System Modules. The length of the

cable is increased from 2 meters (78.74 inches) to 4~5 meters (157.48~196.85 inches).


140 DN09167685 Issue: 01F



g Using of a slightly longer cable (up to 15 m (590.55 in.)) does not cause disorders, but

Nokia cannot guarantee 100% error-free operation in adverse conditions.


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8 Appendix A

RET support shall be available in incremental basis:

• Basic RET support available in RG30 EP1.

• Dynamic calibration and configuration of RET devices is planned to be available in

EX5.1 MP1.

• Multi-RET support, if agreed, is planned to be supported in the future – currently it

has been removed from the current implementation due to limitations on RFM side

and Vendor availability.

• RET chaining is planned to be supported in the future release (RG40)

Appendix A Flexi Multiradio 10 Base Station EDGE FeatureDescriptions

flexi multiradio 10 bts edge feature descriptions

Documents