移动通信技术文档13lecture

MRPand1/3reuseTighterFrequencyReusewithEricssonGSMEricsson(China)CompanyLtd.

Contents

1.OverviewofFrequencyReusetraditionalnon-FH4/12(orvariations)MRP(MultipleReusePatterns,FH)1/3orvariations(non-FHBCCH,“3”reuseonTCH)FrequencyreusesolutionsAAAAAAAA4/121/3MRP

Contents

1.OverviewofFrequencyReuse

2.FrequencyHoppingSchematicpictureofmultipathfadingattwodifferentfrequenciesandatfrequencyhoppingbetweenthetwofrequenciesforaslowlymovingmobilestation.FrequencyDiversityMSdistributionAcceptableC/IFHOPAcceptableC/InoFHOPTheimpactoffrequencyhoppingontheC/IdistributionBenefitsofFrequencyHopping

Frequencyhoppingwillgiveanimprovedspeechquality.Thebenefitsare:amoredependableandpredictableradioenvironment,apossibilitytogivethesubscribersagenerallyuniformspeechquality,apossibilitytodecreasethecellplanningmargin,whichmightbeusedtoemployatighterfrequencyre-useyieldingacapacityincrease.Frequencydiversity&InterferenceaveragingBasebandhoppingRoutingofburstsfromtheTRXtothetransmitteratbasebandhopping.EachtransmitteroperatesonaFIXEDfrequency.Attransmission,allbursts,irrespectiveoftowhichconnectiontheybelong,areroutedfromTRXtothetransmitteroftheproperfrequency.theburstsofoneconnectionmaybetransmittedbyseveralTRX.BothHybridandFilterCombinerSynthesizerhoppingSendingburstsfromtheTRXtothetransmitteratsynthesizerhoppingOnetransmitterhandlesallburststhatbelongtoaspecificconnection.Thetransmittertunestothecorrectfrequencyattransmissionofeachburst.No.offrequsedforhoppingisnotdependentonno.oftransmitter.OnlyHybridCombinerSynthesizerHoppingBasebandHoppingFiltercombinerscanbeused.Thismakesitpossibletousemanytransceiverswithouthavingtoconnectseveralcombinersincascade.notpossibletousealargernumberoffrequenciesinthehoppingsequencethantherearetransmitters.TCHsonBCCHcarriercanalsohop.MRPusuallyuseBasebandHopping.Thenumberoffrequenciesthatcanbeusedforhoppingisnotdependentonthenumberoftransmitters.Hybridcombinershavetobeused.ThistypeofcombinerhasapproximatelythreedBlossmakingmorethantwocombinersincascadeimpractical.TCHsonBCCHdonothop(oruseextraTXtomakeithop).1/3reusecanonlyuseSyntheizerHopping.MRP1/3reuseCyclicfrequencyhoppingHSN=0________________________________...,f4,f1,f2,f3,f4,f1,f2,f3,f4,f1,f2,...________________________________RandomfrequencyhoppingHSN=1~63________________________________...,f1,f4,f4,f3,f1,f2,f4,f1,f3,f3,f2,...________________________________Cannotgivefullinterferenceaveraging!________________________________...,f1,f4,f4,f3,f1,f2,f4,f1,f3,f3,f2,......,f2,f1,f1,f4,f2,f3,f1,f2,f4,f4,f3,......,f3,f2,f2,f1,f3,f4,f2,f3,f1,f1,f4,......,f4,f3,f3,f2,f4,f1,f3,f4,f2,f2,f1,...________________________________OrthogonalsequencesCarriersinasamecellwillbegiventhesameHSN.Inordernottointerferewitheachother,theymustnotusethesamefrequencysimultaneously.Thisisachievedbyafrequencyoffset(MAIO).Itisautomaticallyassignedtoeachchannelatconfiguration.Thisiscalledorthogonality.Allchannelsinoneandthesamecellononeandthesametimeslotmustalwaysbeorthogonal,sincenon-orthogonalchannelswillcauseco-channelinterferencetoeachother.Independentsequences______________________________________Cell1:...,f1,f4,f4,f3,f1,f2,f3,f1,f3,f4,f2,...______________________________________Cell2:...,f3,f1,f1,f1,f4,f3,f2,f1,f2,f1,f4,...______________________________________Cell3:...,f3,f4,f3,f3,f2,f1,f4,f1,f3,f2,f1,...______________________________________Fortheinterferenceaveragingmechanismtoworkwell,thesequenceoffrequenciesinco-channelcellsmustbedifferent(differentHSN).

Thisisevenmoreimportantifthecellsuseexactlythesamefrequencyset.Sequencesofthistypearecalledindependent.Ifthefrequenciesareindependent,theywillonlyinterferewitheachothernowandthen.

1/3reuseSincethereisonlyonecyclicsequence,cyclicsequencescanbeorthogonal(iftheyhavedifferentMAIO),butneverindependent.Thisisthereasonwhycyclicfrequencyhoppingcannotgivefullinterferenceaveraging.基带跳频与射频跳频的比较

Contents

1.OverviewofFrequencyReuse

2.FrequencyHopping

3.MRP

MULTIPLEREUSEPATTERNS-MRPMultipleReusePatterns(MRP)isagenericmethodforachievinghighcapacityusingtightfrequencyreuseincombinationwithfrequencyhopping.TheMRPtechniqueexploitstheadvantagesfromfrequencyhoppinginordertoincreasethecapacity.

ThefundamentalideawithMRPistoapplydifferentseparatereusepatternswithdifferentdegreesoftightnessandusefrequencyhoppingtocombinethemintoanaveragereuse.

EricssonMRP-MultipleRe-UsePatterns12/9/6/4MRPExample4TCHFrequencies6TCHFrequencies9TCHFrequencies12BCCHFrequenciesTRU1TRU2TRU3TRU4TRU1TRU2TRU3MultipleReusePatterns-MRP

7.5MHz1234567891415161718192021222324252627282930313233343536371213BCCHTCHgroup1TCH2TCH41011TCH3BandsplitThefirststepwithMRPistosplittheavailablefrequencyspectrumintodifferentbands.OnebandistheBCCHbandwhichmeansthatafrequencyusedasaBCCHfrequencyinonecellwillnotbeusedasaTCHfrequencyinanothercellandviceversa.ThereasonsreservinguniqueBCCHfrequenciesare:SpecialprotectBCCHchannelSimplifiedneighborcelllistplanning:ReplanningofTCHfrequencieswillnotaffecttheBCCHfrequencyplan.Asanextstep,theMRPmethodimpliesthattheremaining(TCH)frequenciesaredividedintodifferentbands.Thus,oneBCCHandseveralTCHbandswillexist.ThemainideawithseveralTCHbandsistoapplydifferentreusepatternsondifferentTCHtransceivers.ThereasonsforsplittingtheTCHfrequenciesintodifferentbandsare:

Dimensiontheaveragefrequencyreuseaccordingtothetransceiverdistributionofthenetwork

SmallimpactonexistingfrequencyplanwhenaddingmoretransceiversAstructuredwayoffrequencyplanningImplementingtightfrequencyreusebyusingMultipleReusePatterns(MRP)withfrequencyhoppinginGSMhasbeenproventobeanefficientwaytoincreasetheradionetworkcapacitywithminimalcostsforanoperator.Fieldtestsfromlivenetworksshowthatitispossibletoimplementanaveragefrequencyreuseofwithoutjeopardizingthenetworkquality.WithMRP,itispossibletoadjustthetightnessofthefrequencyplanaccordingtothetransceiverdistribution.Atthesametime,MRPprovidesarobustfrequencyplanwhichisveryinsensitivetochanges,e.g.additionoftransceivers.

BenefitsofMRP

Contents

1.OverviewofFrequencyReuse

2.FrequencyHopping

3.MRP

4.1/3reuse1/3ReuseStaggeredBCCH14

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111315171942123252729Notethat1/3reusecanonlyappliedontheTCHfrequencies.TheBCCHfrequenciesmuststilluseasparsereuseforsatisfactorycontrolchannelperformance.No.offrequenciesislargerthanNo.ofTRXsHigherFrequencyHoppingGain!CloserReuseDistance!SynthesizerHopping:Twochannelgroups(saveoneTX)(oruseanextraTXtomakeBCCHhop)

CHGR=0CHGR=1Non-hoppingBCCH!

FilterCombinercannotbeused!TCHFrequenciesaredividedinto3groups.Frequencygroupsarereusedpersite!AAAAAAAAAIndependentsequencesdifferentHSN______________________________________Cell1:...,f1,f4

,f4,f3

,f1,f2,f3,f1

,f3

,f4,f2,...______________________________________Cell2:...,f3

,f1,f1,f1,f4,f3,f2,f1

,f2,f1,f4,...______________________________________Cell3:...,f3

,f4

,f3,f3

,f2,f1,f4,f1

,f3

,f2,f1,...______________________________________EasytoPlan,Expand!BBBBBBBBBCCCCCCCCCSplitthespectrumbetweenNon-hoppingBCCHandhoppingTCH13-15BCCHsmightbeneededincaseofablockedBCCHInanFLPnetwork,itmightbebeneficialtoconsiderusingablockedBCCHplaninordertoreachmaximumcapacity.PlanningBCCH1/3groupplanningforTCHThe1/3groupplanningmethodologyisverysuitedfornetworkswiththree-sectorsitesandratherregularantennadirections.Itisrecommendedtohopoveratleast5frequenciesinordertoachievesufficientfrequencyhoppinggain.Howtodoa1/3reuseplanningHowtodoexpansionina1/3reusenetwork?ExpandcellswithmoreTRXsVerysimple,noneedtodoanewfrequencyplan!!AddingnewsitesOnlyneedtoplanBCCHFractionalLoad(1/3and1/1)AllresourcesarenotusedsimultaneouslyMorefrequenciesassignedtoeachcellthanthenumberofTRXs,i.e.synthesizerhoppingisusedFrequenciesreusedatclosedistance-butinterferenceissharedbetweenallcallsFrequencyLoad(FractionalLoad)FrequencyLoad=Erlangcell/(8*#freqcell)#TRU<#freq,higherhoppinggainrelatestointerferencelevelsof1/3networksItreflectshowmuchtimeafrequencyisbeingtransmitted.Themaximumfractionalloadingcanbeverydifferentfordifferentnetworksbecauseofdifferentradionetworktopologyandce