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Cellular Network Planning andOptimization

Part XII:ExamplesJyriHmlinen,

Department ofCommunications andNetworking,

TKK,21.2.2008

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Note

Allexercisesarepotentialexaminationproblems

Allexamplesinlecturesarepotentialexaminationproblems

Notallexaminationproblemsarecomputationalinnature

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Exampleproblems

Thesignalfading:Explainthefollowingtermsinfewsentencesandanswertothequestions.

Pathloss.Nametwopathlossmodels.

Shadowfading.Whatdistributionisusedtomodelshadowfading?

Fastfading.Whatisfastfadingcoherencedistance?

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Exampleproblems

Pathlosscanbegiveninagenericform

ExplainthemeaningofparametersnandR.Whatistheinterval[a,b]wherenisexpectedtovary?

ConsidertheOkumura-Hata modelandcompute

thedecreaseinpathlosswhenbasestationantennaisincreasedby5meters.Carrierfrequencyandmobilestationantennaheightremainthesame.

)(log1010

RnAL +=

( ) ( )10 10 10 10log 13.82 log 6.55log logc b m bL A B f h a h C h d= + +

(1)

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Exampleproblems

Explainthefollowingtermsusingfewsentences

co-channelinterference

adjacentchannelinterference

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Problem

LettheSINRbegivenas

whereRisthecellrange,Disthereuse

distance(distancetonearestco-channelcell),NisnoisepowerandPistransmissionpower.

ForagivenSINRrequirementandpathloss

exponent,computeSNRonthecelledgefordifferentclustersizes.

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Givenfigure

2.5 3 3.5 4 4.5 56

7

8

9

10

11

12

13

C()

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Problem

UseSINRmodelwhere

Assumethatsystemisinterferencelimitedand

numberofgivenchannelsis20,requiredSINRis9dBandpropagationexponent(pathloss

exponent)is4.Computetheclustersize.Whatisthenumberofchannelspercell?

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Problem

Assume anantenna inwhich there are 6/2dipoles ontopofeach other so that narrow

vertical beam can be formed. What isantenna gain (indBis)ofanideal panel

antenna when horizontal 3dBbeam width is65

degrees (3-sectorsite)?

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Example

GSM900with20Woutput Lossesandgains

Combiner:-3dB Diplexer-0.5dB

Feedercable-2.5dB

Antennagain+17dBi

Total+11dB

EffectiveIsotropicRadiatedPower(EIRP) EIRP=43dBm+11dB=

54dB(=251W)

GSM900

GSM1800

TRX/f1

TRX/f2

Combiner

Diplexer

Feeder

cable

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Problem

Assume that Operator has 5MHzavailable forGSM

Operator makes theTCHfrequency plan according tospecifications (SINR>9dB)but add 6dBmarginal forBCCHSINR.

Propagation exponent is4,system isinterference

limited Problems

What are thecluster sizes forBCCHandTCH?

How many TRXs are needed What isthenumber ofTCH/FandTCH/Hspeech

channels percell?

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Problem

Whatisfrequencyhopping?Whyitisused?Explainatleasttwogainmechanisms.Whatare

commonbandstrategyanddedicatedbandstrategyforfrequencyhoppinginGSMnetwork?

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Problem

LinkbudgetcalculationforGSM

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Problem

WhatarethedifferencesbetweenWCDMAspreadingandscramblingcodes?Forwhat

purposesspreadingandscramblingcodesareusedinWCDMA?

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Problem

NameWCDMAQoS classesandgiveanexampleapplicationforeachclass.Namealso

QoS parameters.

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Problem

WhyRadioResourceManagement(RRM)issoimportantforWCDMA?WhataremainRRM

functions?

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Problem

Explainbrieflythepurposeofthefollowingfunctions

Fastpowercontrol(=transmitpowercontrol)inUL

OuterlooppowercontrolinUL

SofthandoverinUL.Whatisdifferencebetweensoft

andsofterhandover? Admissioncontrol

Congestioncontrol

Packetscheduler

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Problem

ExplainbrieflySHOreportingevents1aand1bandrelatedreportingranges.Whathappensin

thegivenfigure(notexplicitlystatedinthisexample)?WhytheseparametersareimportantinWCDMAnetworkplanning?

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Problem

WCDMAUL/DLlinkbudgetcalculationproblem

ULloadequationproblem

DLloadequationproblem

DeduceULloadequation

DeduceDLtransmissionpowerneededinbasestation

Nameallparametersinequations

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Problem

RelatedtoWCDMAlinkbudgetcomputationexplainbriefly

Fastfadingmargin(=powercontrolheadroom)

Shadowfadingmargin

Interferencemargin

HowWCDMAcoverageandcapacityareconnected?

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Problems

WhycorrectantennatiltissoimportantforWCDMA?Nametwowaystoimplementtheantennatilt.Whatis

thedifferencebetweenmethods? WhatispilotpollutioninWCDMA?Howtheso-called

activesetandpilotpollutionarerelated?Whatnetworkplanningandoptimizationmeanswehaveagainstpilot

pollutioninWCDMA?

WhataresoftandsofterhandoverinWCDMA?Explainbothuplinkanddownlinksoftandsofterhandovers.Why

softhandoveroptimizationisimportantinWCDMA?Whatisactiveset?Whatismonitoredset(=neighbourlist)

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Problems

WhatarethemaindifferencesbetweenWCDMAandHSDPAsystems?

WhatisChannelawarescheduling?Explainwhatmulti-userdiversityis.Drawafigureinordertosupportyourexplanation.

Explainhybridautomaticrepeatrequest

Explainadaptivemodulationandcoding