Radio NW Planning

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March 9, 2000 Copyright: Jaakko Lhteenmki1INFORMATION TECHNOLOGY

Jaakko LhteenmkiVTT Information Technology

P.O. Box 1202, FIN-02044 VTT, Finland

Tel: +358 9 4566547Fax: +358 9 4567013

E-mail: + [email protected]

Optimising Next Generation Mobile NetworksICM Conference 9-10 March 2000


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Radio network planning =Determination of- cell locations- cell antenna types and pointings- carrier frequencies and- system parameterswith the objective of meeting the requirements for

capacity and quality of service (QoS)


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2000 2001 2002

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Universal MobileTelecommunications System

Enhanced Data Modulationfor GSM evolution

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3-fold data-rate increase by 8-PSK modulation

Higher received signal level requiredDecreased service area

Increased offered trafficImproved data transmission

Packed-mode transmission New traffic models

Higher power threshold in planning

, or


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Several radio interfaces are being harmonised and willincluded in global IMT-2000 standard by the ITU:

CDMA TDD

TDMA

TDMA & FDMA

CDMA direct spread

CDMA multi carrier


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Multi-rate services to be taken into account Frequency planning not needed

Resource allocation carried out by controlling cell

density and parameters Macro-diversity and soft handover

Adaptive antennas

Important effect of channel impulse response

Multi-user detection (MUD)


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Start

Offered traffic density

Estimated cell capacity

Required cell density

Code planning

Parameter planning

Network simulation

Result analysis

Link-level performance

Coverage planning

no

yesStopNew iteration OK?

Focus of the presentation


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The performance of the up-link and down-linkconnection is evaluated by simulation.

Performance is characterised e.g. by SIR - BER (1 curve

(1 Signal to Interference Ratio - Bit Error Ratio

Simulations for different conditions- radio channel and interference conditions

- receiver types- transmission rates and modes

Usage of results

- product development- receiver threshold values for subsequent planningsteps (network simulation)


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datasource

base-bandprocessing

modulation RFparts

RFparts

demodu-lation

base-bandprocessing

compare

+

radiochannel

performance results: BER, FER, ...

- coding- interleaving- spreading

- de-spreading- de-interleaving- decoding

TRANSMITTER

RECEIVER

interferingsignals

delayamplitudeimpulse response


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Simulated impulse responsesequence (microcell conditions)

01000

2000 3000 4000

50006000

0

10

20

30

40

50

60

-150

-100

-50

delay(ns)

time(s)

amplitude(dB)

Channel model describes the effects experienced bythe signal propagating from transmitter to receiver

Simulated impulse response(open office environment)


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Parameters:

- WCDMA downlink

- chip rate 3.84 Mchips/s- 10 samples per bit- channel model: 6 tapsmicrocell (pedestrian)

- spreading code:OVSF, length 128

- scrambling code:complex Gold

- pulse shaping:

RRC, roll-off 0.22- simulation time: 8 s


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Carried out by using coverage prediction tools

Accurate coverage prediction calls for sophisticatedpropagation models

Specific models for different environments

Indoorand urban areas are most important, because of- high user density

- concentration of high data-rate usersAccurate indoor and urban area coverageprediction is needed

Find base station locations in accordance withcoverage and cell-size requirements


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Received power is a combination of the direct pathand dominant (first order) reflections and diffractions

++= 10101010 101010log10][difrefdir

PPP

r dBmP

= received power along direct path [dBm]dirP= received power along reflected paths [dBm]

refP

= received power along diffracted paths [dBm]difP

Pdir , Pref and Pdif calculated from expressionstaking into account empirical values of wall

transmission and reflection losses (see [2] for details)


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0 100 200 300 400 500-85

-80

-75

-70

-65

-60

-55

-50

Measured (Average 21 pts) Calculated (Average 21 pts)

Point Number

Power[dBm]

Statistics

Mean Error: -2.17

RMS Error: 3.13

Received Power vs. Measurement Point

d:\anetra\antenni1\\t0107.dat

1

2 3

4

5

Measured and predicted results in office building. Pictures from theNPS/i tool (Nokia) user interface.


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Office coverage predicted for two cases at1800 MHz to find optimum antenna location.

Antenna at centre of wall Antenna at corner


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Full 3D ray-tracing

Multiple reflections from building walls and terrain

Penetration into buildings through walls

Multiple diffraction around streetcorners and rooftops

Diffraction around terrain

undulations

Examples of direct,reflected and diffractedpaths from transmitterto coverage area pointsRX1..RX3


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BS

Example ofmicrocellcoverage areapredicted byMCT tool

(Sonera Oyj)


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1) Predict coverage areas for all potential BS sites andantenna installation options taking into account thedesired average cell-size

2) Find out the optimum combination of coverageareas giving the best area coverage with thespecified number of BS sites.

Optimisation carried out by using Genetic Algorithms:- individual = one combination of BS sites andantenna installations

- population = a group of individuals

- iterative search for best individual- at each iteration new individuals derived from thepopulation by using the GA- operations


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More information: K. Lieska, E. Laitinen, J. Lhteenmki, FrequencyAllocation with Genetic Algorithms, Proc. of the PIMRC99, Osaka, Sept.12-15, 1999.

Service area: city centre3x4 km

Potential BS sites: 70 Pixels: 120000

Allowed BS sites: 27

Results

- 99% of best possiblecoverage reached in< 100 iteration steps

Co

veragepoints(x1

000)


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Start

Initialise network

Move users

Calculate SIR

Execute power control algorithm

Stop/initiate connections

Generate simulation environment

noyesStop

Execute handover algorithm

Continue?

SIR = signal to interference ratio


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Generate simulation environment

Retrieve Information from link-levelsimulation

Number of subscribers per area

Traffic, service and mobility profiles

Required QoS for each service

BS locations and parameters

Predicted coverage information

System parameters

Initialise network

Locate BS-MS connections on map

Use predicted coverage areas forevaluation of up-link and down-linkSIR

Calculate SIR

Execute handover algorithm

Carry out handover if necessary

Execute power control algorithm

Change transmit powers if required

Stop / initiate connections

According to statistical distributions:- stop existing connections- initiate new connections

New iteration / stop

If simulation time has not beencompleted, start new simulation

iteration


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Blocking rate. The probability that a call can not beestablished when requested.

Call dropping rate. The probability that a call isinterrupted.

Quality of Service (QoS). Includes different issues fordifferent services. For example, in packet services

the packet throughput and packet delay are mostimportant.

Power level statistics. The proportion of different

power levels used at MS and BS. Handover rate.


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Overview on planning aspects 3G systems has beengiven with emphasis on link-level and networksimulation as well as coverage prediction.

Link-level simulation reveals basic performance of thesystem for different radio channel conditions andprovides input formation for other planning steps.

Coverage planning takes advantage of specific indoorand outdoor propagation models to meet highprediction accuracy requirements

Network simulation predicts the performance of thenetwork


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[1] T. Ojanper, R. Prasad, Wideband CDMA for third

generation mobile communications, Artech House,1998.

[2] E. Damosso, L. Correia, Digital mobile radio towards

future generation systems, European Commission,

Directorate General XIII, Belgium, 1999.


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CDMA Code Division Multiple Access

DECT Digital European Cordless Telecommunications

EDGE Enhanced data modulation for GSM Evolution

ETSI European Telecommunications Standards Institute

FDD Frequency Division duplex

FDMA Frequency Division Multiple Access

GPRS General Packet Radio Service

HSCSD High-Speed Circuit Switched Data

ITU International Telecommunications Union

SIR Signal to Interference Ratio

TDD Time Division Duplex

TDMA Time Division Multiple Access

UMTS Universal Mobile Telecommunications System

UTRA UMTS Terrestiral Radio Access

WCDMA Wideband Code Division Multiple Access

Documents

Radio NW Planning