lte features in ics designer v2

LTE features – ICS designer v2

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SOFTWARE DESIGNERS: P & D MISSUD

LTE FEATURES – ICS DESIGNER V2

of 27 The following manual is copyright protected and remains the exclusive property of ATDI. No part of this manual, in whole or in part, may be copied or reproduced in any way without prior written authorization of ATDI.

VERSIONS HISTORY

Version Date Writer

LTE features – ICS

designer v2 version

Remarks

0.1 03/01/2013 NEDHIF Sami 2.2.9

Limited Warranty

This manual is subject to the limited warranty conditions as specified by the general operating

license of the whole package. ATDI reserves the right to modify this manual without prior

warning.



TABLE OF CONTENTS Versions History....................................................................................................................................... 2

Table of Contents .................................................................................................................................... 3

1. INTRODUCTION ............................................................................................................................... 4

2. LTE modeling requirements ............................................................................................................ 5

2.1. LTE propagation modelling in ICS designer ............................................................................. 5

2.2. Target requirements for LTE network design .......................................................................... 8

3. LTE parameters overview ................................................................................................................ 9

3.1. General parameters ................................................................................................................ 9

3.2. System overhead parameters ............................................................................................... 10

4. Coverage prediction ...................................................................................................................... 12

4.1. General LTE features in ICS designer ..................................................................................... 12

4.2. Statistical method based on Monte Carlo method ............................................................... 14

5. LTE capacity planning .................................................................................................................... 21

5.1. Peak throughput .................................................................................................................... 21

5.2. Scheduler methods ................................................................................................................ 23

5.3. LTE general workflow in ICS designer .................................................................................... 25



1. INTRODUCTION

Scope of the white paper

This document provides a comprehensive overview of the LTE features in ICS designer. The goal of this

white paper is to give an understanding of the capabilities of the tool and how it can help users to build

and improve their LTE network design. This following document also focuses on the LTE Monte-Carlo

simulator in ICS Designer which can be used to validate and optimize the LTE network dimensioning

with a very easy and efficient way. This solution is very useful to improve the coverage and interference

KPIs (RSCP, RSRQ, PUSCH, and SNIR-PDSCH) but also the throughput targets.

Who should read this white paper?

RF Engineers responsible for LTE network design (mobile and TETRA systems), enhancing cellular

performance and implementing wireless system optimization.

Engineers or students looking to further theorical understanding of the LTE networks. Experienced technicians involved in field optimization.

Anyone looking to maximize the return on investment with ICS design software.

Prerequisites Familiarity with network infrastructure and operation of the air interface.

A general understanding of LTE technologies.

Familiarity with the ICS Designer software.



2. LTE MODELING REQUIREMENTS

2.1. LTE propagation modelling in ICS designer

Propagation modeling itself is technology independent area. Good propagation modeling is crucial for

exact network planning and dimensioning

Various LTE propagation models are supported in ICS Designer:

� Usual empirical models such as Okumura-Hata, COST 231 models, …

� LTE 3GPP models (based on 3GPP TR 36.942 V8.3.0 recommendations)

� Geometrical models used for free space attenuation, diffraction loss and the subpath loss

calculation. ATDI’s experience in using practically geometrical models (comparisons with

measurements and customer remarks) allows providing acceptable prediction (compare to

empirical models) even without any calibration of the propagation models. Those last models

are very flexible because it allows to support any kind of LTE scenarios (from Network mobile

operator or TETRA operator point of view) especially when the LTE receiver is a mobile UE,

airplane or helicopter (for police, emergency or military operations). The geometrical models

allows also to support inter technology analysis between LTE and UMTS, GSM and digital

broadcast network for potential additional coexistence studies.

Empirical models

Okumura-Hata COST 231

Frequency Range 150 MHz to 1.0 GHz

1.5 to 2.0 GHz

1500 MHz to 2.0 GHz

eNodeB Antenna Height

30 to 200 m

above roof-top

30 to 200 m

above roof-top

UE Antenna Height 1 to 10 m 1 to 10 m

Range 1 to 20 km 1 to 20 km

Table 1: Applicability of the Okumura-Hata and Cost 231 propagation models

3GPP LTE Empirical models (TR 36.942 V8.3.0)

3GPP RURAL 3GPP URBAN

Frequency Range 150 MHz to 1.0 GHz

1.5 to 2.0 GHz 800 MHz to 2.0 GHz


30 to 200 m

above roof-top

4 to 50 m

above roof-top

UE Antenna Height 1 to 10 m 1 to 3m

Range 1 to 20 km 30 m to 6 km

Table 2: Applicability of the 3GPP propagation models



Geometrical models

ITU-R 525 (Free space model)

Deygout 1994 (Diffraction model)

Standard/Coarse Integration/Fine Integration

(Subpath models)

Frequency Range

All E-UTRAN band + UMTS band +GSM band +VHF band (include Digital broadcast band)

All E-UTRAN band + UMTS band +GSM band

+VHF band (include Digital broadcast band)

All E-UTRAN band + UMTS band +GSM band +VHF band (include

Digital broadcast band)


Any value

Any value

Any value

UE Antenna Height

Any value

Any value

Any value

Range

Any value

Any value

Any value

Table 3: Applicability of the geometrical propagation models

The propagation model should be adjusted to the environment in which the sites will be built up.

This means that propagation measurements and tuning of the model are recommended for real

network deployment. The best results found without tuning are geometrical models.

Various propagations models implemented means:

− Standards empirical models and deterministic models can be calibrated and used when the site are deployed.

− More flexibility in term of time of calculations. − E-UTRAN FDD/TDD, UMTS FDD/TDD, TETRA and broadcast bands are fully supported

in the same project (when deterministic model is used).



Fig1: Propagation model window in ICS Designer

Fig2: RSCP coverage prediction using Fig3: RSCP coverage prediction using

3GPP urban propagation model deterministic propagation model



Fig4: RSCP coverage prediction using

Cost 231 propagation model

2.2. Target requirements for LTE network design

All LTE Features in ICS Designer has been implemented according to the technical specifications for LTE

air interface (3GPP Release 9) especially the following points:

OFDMA and SC-FDMA

Support of FDD and TDD Frame structure

Resource blocks mapping

Scalable Channel Bandwidths (1.4, 3, 5, 10, 15 and 20 MHz)

Short and long cyclic prefixes

Support of QPSK, 16QAM and 64 QAM modulations

Downlink and Uplink Control Channels and Overheads

Physical and control channels setting (Reference signal, PDSCH, control channels)

Single antenna port, MISO

Multiple Input Multiple Output (MIMO)

o Single antenna port, MISO

o MIMO Spatial Diversity

o Tx Div (Transmit diversity)

o MIMO Spatial Multiplexing

o Modeling of Multi user MIMO

o AAS (Antenna Adaptive Switch)



3. LTE PARAMETERS OVERVIEW

3.1. General parameters

Parameter name Description

Operating band Frequency band allocated to the network operator for the LTE network to be

coverage-dimensioned

UE power class This parameter represents the User Equipment (UE) power class that is to be

assumed.

Channel bandwidth

This parameter defines the frequency bandwidth that is avail-able to the

operator. The bandwidth basically determines the maximum capacity limits

of the considered configuration -further capacity limiting factors (such as

overhead and unused symbols) are to be considered in addition. Notes: If a

fair comparison between Frequency Division Duplex (FDD) and Time Division

Duplex (TDD) is to be made, it is legitimate to set a two times wider

bandwidth for TDD in order to reflect the same spectrum occupation.

Frame structure

This parameter represents the type of the frame structure: E-UTRAN has

introduced two kind of radio frame: Type 1: Frame structure (FDD) and Type

2: Frame structure (FDD)

LTE Operating Band:

3GPP defines several bands available for LTE FDD and TDD deployment. The mapping scheme always

allocates the UL to the lower carrier frequency in order to provide the best possible coverage

performance.

E-UTRAN

Band

UL frequencies DL frequencies Band

separation

Duplex

mode Lowest Highest Lowest Highest

1 1920 1980 2110 2170 130

FDD

2 1850 1910 1930 1990 20

3 1710 1785 1805 1880 20

4 1710 1755 1805 1880 355

5 824 849 869 894 20

6 830 840 875 885 35

7 2500 2570 2620 2690 50

8 880 915 925 960 10

9 1749.9 1784.9 1844.9 1879.9 60

10 1710 1770 2110 2170 340

11 1427.9 1452.9 1475.9 1500..9 23

12 698 716 728 746 12

13 777 787 758 768 40

…

17 704 716 734 746 18

…

20 832 862 791 821 11

Lowest Highest

33 1900 1920

N/A TDD

34 2010 2025

35 1850 1910

36 1900 1920

37 2010 2025

38 2570 2620

39 1880 1920

40 2300 2400

Table 4: E-UTRAN operating band (FDD/TDD)



E-UTRAN channels bandwidth configuration:

Scalable channel bandwidth is one of the biggest advantages of the LTE air interface. E-UTRAN can

operate in a channel bandwidth range from 1.4 MHz up to 20 MHz as presented in the tab 2. LTE

operators will be able to implement various frequency bands and exploiting the bandwidth scalability

in case of very limited frequency resources. It also allows migration from the legacy systems (e.g.

GERAN, UTRAN) or assignment of small bandwidths in the initial deployment phases.

The bandwidth configuration impacts factors such as overhead ratio and total cell throughput. The

best network performance (regarding maximum peak data rates and cell throughputs) is achieved by

the deployment of 20 MHz bandwidth. One should expect certain performance degradation

especially for 1.4 MHz and 3 MHz bandwidth because of worse scheduling gain as well. As can be

seen in Table 5, every bandwidth configuration features a defined number of so-called Physical

Resource Blocks (PRB).

Bandwidth [MHZ] 1.4 3 5 10 15 20

No. Of PRBSs 6 15 25 50 75 100

Subcarriers spacing 15 kHz Table 5: E-UTRAN channels bandwidth configuration

The minimum allocation to a UE is 1 Resource Block (RB) over a subframe.

3.2. System overhead parameters

This section presents description of the LTE system overhead parameters for control channels. Those

parameters are required for the e-nodeB setting and have an important impact in the sharing of the

total transmitted power and the dimensioning of the LTE network.

Parameter name Description Reference

Total number of PRBs per time

transmission interval (TTI)

Number of Physical Resource blocks (PRB) in

frequency domain. This number is defined by the

Bandwidth parameter.

Cyclic prefix (CP)

This parameter defines the type of the cyclic prefix

(extended or normal). The cyclic prefix type influences

the capacity of a PRB in the time domain: 1 TTI (1slot)

either contains 7 symbols (cyclic prefix=normal) or 7

symbols (cyclic prefix=normal). Extended cyclic is

recommended for the LTE network deployment.

Number of Orthogonal

Frequency Division

Multiplexing (TTI) symbols per

subframe

This parameters depends of cyclic prefix. It calculates

the number of symbols available within a subframe

(1ms or 1TTI): 14 symbols when cyclic prefix is normal

or 12 symbols when cyclic prefix is extended.

Number of Physical Downlink

Control Channel (PDCCH)

symbols per subframe

This parameters defines the number of symbols used

by PDCCH within one subframe (range between 0 and

4). Four symbols are reserved for small bandwidth

configuration due to the need for robustness and

signaling capacity. This parameter is relevant for the

DL overhead calculation.

3GPP 36.211,

section 6.8



Number of PRBs for physical

Uplink Control channel

(PUCCH)

This parameters defines how many PRBs are consumed

by the PUCCH within one subframe. 3GPP 36.211,

section 5.4.3

Random Access Chanel

(RACH) density per 10ms

This parameters defines which frequency a RACH

reservation is repeated. This parameter is relevant for

UL overhead estimation.

3GPP 36.211,

section 5.7

Reference signal (RS)

This parameter represents the overhead (in %) used for

the reference signals in DL and UL. This number

depends of deployed antennas/antenna ports:

− Four resources element per PRB in case of one

antenna.

− Eight resources element per PRB in case of two

antennas.

− Twelve resources element per PRB in case of for

antennas.

3GPP 36.211,

section 6.10.1

Primary Synchronization

Signal (PSS)

This parameter represents the overhead (in %) used for

primary synchronization signal in DL and UL.

Mapping of the resource Elements (PSS and SSS):

Two last OFDM symbol in timeslot 0 and 10 in every

radio frame. 72 subcarriers (1.08MHz) occupied in

every symbol dedicated for synchronization channel.

3GPP 36.211,

section 6.11

Physical broadcast Channel

(PBCH)/ Packet Random

Access Channel (PRACH)

This parameter represents the overhead consumed by

for the PDCCH (DL, calculated by dividing the PBCH

resources by the overall amount of resources) and

PRACH (UL, calculated considering the setting of RACH

density)

3GPP 36.211,

section 6.6

Physical Uplink Shared

Channel (PUSCH) Uplink

Control Information (UCI)

Uplink Control Information multiplexed with user data

when PUSCH is scheduled (Channel Quality Indicator-

CQI), Precoding Matrix Indicator (PMI), Resource

Indicator and acknowledgment (ACK)/Negative

Acknowledgments (NACK).

3GPP 36.211,

section 5.5.2.22

The table below presents an example of system overhead estimation for downlink and uplink:

Physical

channel/signal

Channel bandwidth

[MHz]

1.4 3 5 10 15 20

Reference signal 9.52% 9.52% 9.52% 9.52% 9.52% 9.52%

Synchronization

signals 2.86% 1.14% 0.69% 0.34% 0.23% 0.17%

PBCH 2.62% 1.05% 0.63% 0.31% 0.21% 0.16%

PDCCH 19.05% 19.05% 19.05% 19.05% 19.05% 19.05%

Total 34.05% 30.76% 29.89% 29.23% 29.01% 28.90%

Table 6: Example of Downlink signaling overhead

Physical

channel/signal

Channel bandwidth

[MHz]

1.4 3 5 10 15 20

Reference signal 11.90% 12.38% 13.14% 13.14% 13.14% 13.14%

PRACH 10.00% 4.00% 2.40% 1.20% 0.80% 0.60%

PUCCH 16.67% 13.33% 8.00% 8.00% 8.00% 8.00%

PUSCH UCI n/a 2.71% 2.03% 1.20% 0.86% 0.71% Total 38.57% 32.42% 25.57% 23.54% 22.80% 22.45%

Table 7: Example of Uplink signaling overhead



Fig5: DL and UL overhead comparison

We can notice that the small bandwidth of 1.4 MHz is significantly impacted by controlling resources,

whereas the effect is much smaller for bandwidth higher than 5 MHz

E-UTRAN overhead configuration:

It is recommended to assume 3 OFDM symbols per TTI for PDCCH to account for maximized controlling

region capacity. The cell-specific Reference Signal overhead depends on the number of active antenna

ports (it is two times higher for dimensioning with transmit diversity at the cell-edge). These are two

most important factors impacting dimensioning and capacity results. The rest of DL PHY channels and

signals can be neglected. For uplink control channel (PUCCH) it is recommended to assume 1 PRB

(1.4MHz), 2 (3 and 5 MHz), 4 (10 MHz), 6 (15 MHz), 8 (20 MHz).PRACH density (number of PRACH

resources per radio frame) can be set to 1which means that one PRACH resource (consisting of 6 PRBs)

is reserved per every radio frame. It obviously depends on the subscriber profile (i.e. service usage,

mobility, etc.).

4. COVERAGE PREDICTION

4.1. GENERAL LTE FEATURES IN ICS DESIGNER

This section describes a no exhaustive list of the LTE features in ICS Designer:

− Various transmission modes

o Standard antenna

o SIMO, MISO, TxDiv antennas

o Single and Multi User MIMO (SD/SM)

o AAS (Adaptive Antenna Switch)

− LTE static plots predictions and simulations

o RSRP (dBm), best RSRP, second best RSRP, RSRP overlapping, Max number of RSRP

received…

o RSSI (dBm) Received Signal Strength indicator

o RSRQ (dB)

o SNIR(PDSCH)

o SNIR (Control Channels)

o SNIR (PUSCH) based on the noise rise factor (dB) or Monte Carlo method



− LTE schedulers

o Max SNIR

o Robin Wood (Rodin Robin)

o Fair Enough (Proportional Fair)

− ICIC (Inter Cell Interference Coordination) Enhancement feature

− Static LTE traffic analysis:

o Peak throughput plots based on user defined cell loads (PDSCH channel) and SNIR us

Throughput table.

o QCI and priority bearers based on SNIR(dB)

- Dynamic LTE traffic analysis based on parenting method: RB allocation and throughput

calculation based on UE’s population (can be generated manually or imported via a .CSV file).

The final result is a gglobal LTE Traffic QoS report by subscriber, station or for the entire

network. Throughput and RB allocation distribution will depends on:

� Profile and location of the UE

� Channels setting of the cells and RB capacity dedicated to the traffic channel.

� Transmission mode used: AAS (Antenna Adaptive Switch) mode or fixed mode

(Single antenna port SISO or SIMO, Tx Div/MISO, Spatial multiplexing MIMO, Multi

user MIMO).

� Scheduler method (Max SNIR, RODIN WOOD, FAIR ENOUGH)

� Pre-defined “SNIR vs. Throughput/RB” table

- LTE prospective planning: Automatic search of site to connect the orphan UE (when the UE is

not connected to the e-nodeB) due to a weak level of coverage or traffic congestion.

- Monte Carlo simulator for traffic and KPIs analysis (refers to the section 4.2 “Statistical

method based on Monte Carlo method).

- LTE field strength exposure calculation (2D and 3D modes).

- Coexistence analysis between LTE and DVB-T network

- Resource allocation and optimization:

o PCI (Physical Cell IDs).

o RSI (Root Sequence Index): Several methods are implemented in ICS designer for RSI

planning (PRACH ZC sequence parameter for 3GPP, coverage range, extended radius…)

o Automatic frequency allocation for multi E-UTRAN carriers

- Automatic neighbor cells:

o Intra system (LTE<->LTE)

Connectivity between e-node B and UEs (Min RSCP, Min RSRQ received by the UE and in PUSCH

received by the e-nodeB) are checked then the e-nodeB is allocating the RBs according to the

scheduler method used for the simulation. Once the e-nodeB RBs are allocated for the UE’s, the

throughput offer is calculated according to a SNIR us Throughput (per RB) table map for the

dedicated transmission mode used by the UE.

If the AAS mode is selected, ICS designer will choose the best transmission mode for a given UE giving

the best SNIR performances. Typically TxDiv transmission mode when the SNIR is poor (at the cell

edge) or MIMO mode when the SNIR measured is high (typically when the mobile is close to the

station). Of course, the choice of the transmission mode (when the AAS mode is selected) in ICS

designer is also depending of the characteristics of the UE (EPA05, EPA70)



o Inter system (LTE<->WCDMA, WiMAX)

LTE Handover simulations in ICS designer takes into account various radio levels (RSRP and

RSRQ requirements).

4.2. STATISTICAL METHOD BASED ON MONTE CARLO METHOD

LTE Monte Carlo analysis functions in ICS Designer comprises downlink and uplink Best Server,

Interference and Traffic analysis. ICS Designer performs several random trials, using a pseudo-random

distribution to spread the UE over the map for each trial. The outputs of the analysis are quality and

traffic reports. The Monte Carlo approach is very useful and efficient to validate or enhance the LTE

network parameters in order to achieve the coverage and interference objectives for a given

population of UE. Typically, the LTE Monte Carlo simulators can be used to validate the following

criterions:

For downlink:

− RSCP Levels

− RSRQ levels

− SNIR Levels

For uplink:

− PUSCH levels

Once the e-nodeB network is configured (antenna height, bandwidth, transmitted power...) a

population of UE can be generated (with one or several profiles) can be generated and randomly

distributed on the project by different ways: Per density of km², over configured cells. Once the

population is generated, the tool will calculate the average and the distribution of the coverage KPIs

(RSCP, RSRQ, SNIR PDSCH and PUSCH).

Fig6: LTE Monte Carlo Simulator in ICS Designer



Practical case:

14 LTE sites located in dense urban (Brussel-Belgium) with a trafic scenario based on a UE distribution using between 5 and 20 UE per cell randomly distributed.

e-nodeB parameters

Antenna Height Between 20 and 30

m

Antenna gain 16 dBi

Cable and connector

losses 0.5 dB

Total downlink

bandwidth 25 PRB

Power of Remote Radio

Unit W

Antenna Type

MIMO2X2 Open

Loop

Electrical tilt -6°

Mechanical tilt -2°

Noise floor per

resource block -114dBm

% RS channels 10

%PDSCH channels 70

% control channels 10

% Overhead 10

e-node B sensitivity

(dBm) -122

UE parameters UE max transmit power 23 dBm

Power control Not activated

UE sensitivity -116 dBm

Channel Model VehA 3km/h

UL Receive Diversity 2MIMO

SNIR PDSCH target >= -5dB

In this practical scenario, all the e-nodeBs parameters are fixed (transmitted power, antenna height, tilts…). The above results shows the KPI coverage results with the Monte-Carlo simulator:

Fig7: LTE network in ICS Designer with 2D view

Fig8: LTE network in ICS Designer with 3D view



Fig9: RSRQ (dB) simulation with Monte Carlo simulator

Fig10: RSRQ (dB) distribution with Monte Carlo simulator



Fig11: RSCP (dBm) simulation with Monte Carlo simulator

Fig12: PUSCH (dBm) simulation with Monte Carlo simulator



Fig 13: SNIR (PDSCH) simulation with Monte Carlo simulator

The Monte carlo simulator can also be used to optimize the e-nodeb configuration in order to improve the coverage and interference KPI s parameters. The Monte carlo simulator is able to calculate the KPI distribution over the UE population with taking into account the variability of the e-nodeB parameters especially the folowing:

− Azimuth(°), − Electrical tilt(°) − Antenna height (m) − Percentage of transmit power dedicated to the RS signal − Percentage of transmit power dedicated to the PDSCH

signal − Percentage of transmit power dedicated to the control

channels − Antenna type (transmission mode: Standard, MIMO SM,

Tx Div , MISO, single antenna, SISO, SIMO, MU-MIMO)

For example, It is easy to check the impact in term of RSRQ(dB) and SNIR(PDSCH) when the electrical tilt applied for the e-nodeBs are between -4° and -8°



Fig14: RSRQ distribution simulation with Monte Carlo simulator (Electrical Downtilt = -2°)

Fig15: RSRQ distribution simulation with Monte Carlo simulator (Electrical Downtilt between -4° and -8°)

Fig16: SNIR (PDSCH) distribution simulation with Monte Carlo simulator (Electrical Downtilt = -2°)



Fig17: SNIR (PDSCH) distribution simulation with Monte Carlo simulator (Electrical Downtilt between-4° and -8°)

In this example SNIR(PDSCH), RSCP and RSRQ KPIs are degraded when the electrical downtilt applied to the Tx antennas is too high. The aerial configuration using -2° downtilt seems to be the most adapted for the dimensioning network. In the real LTE network, SNIR(PDSCH) level can be improved by the usage of AAS antennas as shown below with the new Monte Carlo simulation using AAS mode. Note that AAS mode and MIMO antennas doesn’t affect RSRP or RSRQ levels: RSRP doesn’t depend on the number of transmit antennas, as it is measured always from resource elements transmitted by one antenna at a time. The 3GPP has defined RSRP as the average power of a single resource element. The UE measures the power of multiple resource elements used to transfer the reference signal but then takes an average of them rather than summing them.

Fig17: SNIR (PDSCH) distribution simulation with Monte Carlo simulator (Electrical Downtilt = -2° and AAS mode activated)



5. LTE CAPACITY PLANNING

5.1. PEAK THROUGHPUT

Per definition Peak throughput represents a theoretical upper bound on what can be achieved on the

channel in terms of throughput or capacity. It is an ideal case since it assumes no frame erasures and

should not be thought of as a sustainable throughput (refer to Section 5.5 for a definition of maximum

sustainable throughput).

The peak throughput depend on:

− Bandwith configuration (1.4; 3; 5..20MHz)

− SNIR conditions (depends on the path loss attenuations, transmitted power...)

− MCS (Modulation Coding Sheme) achieved

− n°PRB allocated to PDSCH channels

Table of correspondence between SNIR us RB based on vendor recommendations are implemented

on ICS Designer and used for Peak throughput calculations. Those table of correspondence can be

applied for the typical transmission modes (Standard antenna, SIMO, Tx Div, MIMO2x2) used during

a typical LTE deployment. The user is able to modify or to import their own SNIR tables.

Fig18: Table of correspondence between SNIR-PDSCH and Throughput/RB

for Channel models: EPA 5 Hz)

Peak throughput calculation takes into account the following criterions: RSRQ conditions and

transmission mode configuration (fixed transmission mode or AAS Adaptive mode switch antenna).



Peak throughput

plots with LTE

network using

single antenna

Peak throughput

plots with LTE

network using

2X2MIMO

configuration (SU-

SD)

Peak throughput

plots with LTE

network using AAS

configuration

Better SNIR at the cell edge

with TxDiv mode



5.2. SCHEDULER METHODS

The throughput an individual user may experience depends both on the MCS allocated (a function of

the user’s characteristics and channel conditions especially RSCP, RSRQ and SNIR) and on the demands

of other users sharing the channel resource. The sharing of the resources over the users is arbitrated

by the scheduler. ICS Designer can simulate the behavior of the traffic for giving population of users

according to various type of scheduler. ICS designer have introduce a traffic method of calculation

based on the LTE schedulers which allows to determinate what is the best algorithm to apply according

to a given traffic scenario.

The LTE schedulers are the following:

− Max SNIR: The Priority is given to the current user has the greatest signal to noise ratio (SNR). MaxSNR method allocates the radio resource constantly to the user who has the best spectral efficiency and therefore that will provide the best throughput on each EU. However, a negative effect of this allocation is that users close to the e-nodeB always have a disproportionate priority on users further away. When the network is congested, it is also common for mobile located on the cell edge that they don’t access at all to the radio resource. With Max SNR it is impossible to guarantee quality of service even minimal since it is exclusively or almost exclusively dependent on the relative position of the mobile. In addition, the Max SNR has another disadvantage: it does not take into account users' needs when assigning priorities.

− Robin Wood (RR): This method (also called “Rodin Robin”) involves allocating the same amount of RB users. However, the rate actually received will depend on the radio conditions (C / N + I, priority bearers).This method does not take into account the needs of users in terms of desired flow or maximum delay of packets. Users are then assigned a rate that is unrelated to their needs. Round Robin does not take into account the position, capabilities and needs of each user. It allocates the same amount of blindness resource units for all mobile without any possibility of differentiating services and thus ensure any quality of service.

− Fair Enough (PF): This algorithm (also called “Proportional Fair”) is considered as the most appropriate in terms of simplicity and performance. It consists in allocating RB iteratively so that the overall throughput provided to each user increases gradually in the same way. When a user has received that application flow, no more RB is assigned and the execution of the algorithm occurs with other users. The algorithm stops when all users are satisfied or all RB were distributed. UE get equal flow rates. In the end, the users with low demand are always advantaged because their desired flow is almost always provided; they are often fully satisfied In contrast with the other users who require more resources (note that in the case where all users have the same needs, scheduler "Robin Rodin" equivalent to the Max-Min Fair).

Fig19: Parenting LTE module in ICS designer



The user needs to define the profile of the UE (max transmitted power, antenna height, transmission

mode supported, traffic demand…) and generate the population of UE (per density per km² or over a

polygon or per site…) then the LTE parenting function will calculate UE by UE the effective traffic

received based on the selected algorithm. Note that during this parenting, DL and UL radio conditions

are checked (RSCP, RSRQ and PUSCH). The “ICIC enhancement” option can be checked to reduce the

risk of collision between RB transmitted by inter-cells as well the MIMO adaptive switch modes (AAS).



5.3. LTE GENERAL WORKFLOW IN ICS DESIGNER

Set technical parameters

of the e-nodeB

Define or load the LTE

simulation parameter file

(.PRM)

Basic predictions:

-RSRP level

-RSRQ (dB)

-RSSI

-SNIR (control channels)

- SNIR (PUSCH)

- ACP (Automatic Cell

Planning)

-Import of LTE cell

-LTE cell configuration

(import by batch )

-Selection site based on

existing UMTS or GSM

- Propagation models

selection

-Characteristics of the UE

-Distance of calculation

(Km)

-Min RSRP sensitivity

(dBm)

- ICIC Enhancement

- % PDSCH and %

Overhead parameters can

be adjusted according to

the traffic scenario

- RSRP plot

- Best server RSRP,

- second server RSRP,

- Third server RSRP,

- RSRP probability,

- Max number of RSRP

channel

- RSRP overlapping area

2D or 3D coverage

analysis

Automatic frequency

assignment

Automatic or manual

neighbour cell allocation

Automatic or manual

Physical Cell Ids and RSI

allocation Various histogramme

analysis :

- Over the whole projet

- Inside a cluster area

defined by a drawn

polygon

- Arround a predefined

vector path)

Field strenght exposure

analysis (in 2D or 3D

modes).

e-node B setu parameter in ICS designer:

- LTE mode (FDD or TDD)

- Bandwidth configuration (1.4; 3; 5;10; 15 or

20MHz) -

Site location, Antenna height , Cell ID , azimuts

, mecanical tilts

- Antenna mode (nb of Tx/Rx arrays):

-Max transmitted power, %RS power, %

PDSCH power, and % control channels power

-RBs traffic capacity

- RSRP min level

- PUSCH received power min (dBm)

- Min sensitivity (dBm) – Noise Floor value

Potential interference

analysis between the LTE

stations and existing

DVB-T network (Low

channel band)

- Standard antenna

-SIMO, Tx Div

-MIMO spatial multiplexing

-Multi user MIMO spatial multiplexing

-AAS (Antenna Adaptive Switch)

Open an existing project

or create a new one



END OF THE DOCUMENT



3GPP TS 36.104: Base Station radio transmission and reception specifications. 3GPP TS 36.101: User Equipment radio transmission and reception specifications.

lte features in ics designer v2

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