cellular network planning and optimization examples public
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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
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9
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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
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