hsdpa principles seminar

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1、HSDPAPrinciplesSeminarCorradoCarbone-RO/QoSSouth2Agenda3.ChannelStructure2.Architecture1.Overview5.InterFrequencyMobilityPrinciples6.CapacityManagement4.Accessibility&MobilityPrinciples7.KPIs3OutlineLet’sgetusedwiththemainconceptsoftheHSDPA.HSDPAintroducesnewtechnologiesintheUMTSw

2、orldandconsequentlyanewwaytomanagePStraffic.Themostimportantimpactsofitareon:ModulationRetransmissionschemesSchedulingUsageofPowerandCodeThispresentationreportsanoverviewofthemainissuestotakeinmind.4HSDPABasicPrinciples51-SharedChannelTransmission(1/2)Shared-channeltransmissionimp

3、liesthatacertainamountofradioresourcesofacell(codesandpower)isseenasacommonresourcethatisdynamicallysharedbetweenusers.Theideaisthatapartofthetotaldownlinkcoderesourceisdynamicallysharedbetweenasetofpacket-datausers,primarilyinthetimedomain.Thecodesareallocatedtoauseronlywhentheya

4、reactuallytobeusedfortransmission,leadingtoefficientcodeandpowerutilization.ForP4only5codes(SF=16)willbeavailablefortheHSDPAfeatureandtheywillbesharedonatimebase.ChannelizationcodesallocatedforHS-DSCHtransmission5codes(example)SF=16SF=8SF=4SF=2SF=1User#1User#2User#3User#4TTIShare

5、dchannelizationcodes61-SharedChannelTransmission(2/2)TheShared-channeltransmissionallows:Higherpeakbitrate:alltheresourcecanbeallocatedtoasingleuserincaseoflowload.BetterapplicationperformancebeingclosertothemodelTCPhasbeingdesignedfor.Moreefficientutilizationofavailablecoderesour

6、cescomparedtotheuseofadedicatedchannel,i.e.reducedriskforcode-limiteddownlink.TheShared-channeltransmissionimpacts:Schedulingbecomemorecomplex72-Short2msTTI(1/2)TheTransmissionTimeIntervalbecomesextremelyshortinHSDPA;2mscomparedtothe10msusedbyR99highbitrateradiobearer.TheHSchannel

7、sareorganisedinsub-frameof3slotseach;thismeansthattheslottime2/3ms/slotisthesameasforR99slots(10/15ms/slot).Theschedulingandthelinkadaptationalgorithmsworkatthisfrequency!10ms20ms40ms80msEarlierreleases2msRel5(HS-DSCH)2ms82-Short2msTTI(2/2)TheshorterTTIallows:Reducedair-interfaced

8、elay:thisisrequiredbythetheTCPath