关于中继的ofdm系统资源分配算法的研究

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1、AbstractThenext-generationofwirelesscommunicationnetworkswillbringarealsenseoffreedomtocommunicate,andchangethewaywelivecompletely,thus,theperformanceofthesystemhadbeenputforwardhigherrequirements.Orthogonalfrequencydivisionmultiplexing(OFDM)isamaturetechniquetoprovidehigherspectrumu

2、tilizationwhilecooperativerelayingcanprovideanefficientwaytoovercomethedisadvantagesbroughtbywirelessfadingchannel.Thecombineoftheadvantagesofbothtechnologieshasbecomeaneffectivesolutiontothetechnicalproblemsofwirelesscommunicationnetworks.Thisthesisfocusesontheresearchoftheresourcea

3、llocationformulti-userrelayenhancedOFDMsystems.Theemphasisislaidontheresourceallocationofthesingle-cellsingle-relay,thesingle-cellmulti-relayandthemulti-cellmulti-relayOFDMsystems.Differentresourceallocationalgorithmsareproposedforthedifferentscenarios.Thesealgorithmsarebasedonthecor

4、eobjectivetomaximizesystemcapacityandtakingthecomplexityandfairnessofdifferentusersintoaccountaswell.Forthesinglerelayscenario,adual-hopOFDMrelayingsystememployingdecode-and-forward(DF)relayingprotocolisconsideredandalow-complexitysubcarrierandpowerallocation(PA)schemewithfourstepsis

5、proposed.First,thedual-hopsubcarriersarematchedaccordingtotheiractualstrength,thenweallocatethetotaltransmitpowerbetweensourceandrelaywithrespecttotheiraveragechannelattenuationoffirstandsecondhop.Afterwards,wereformulatetheoriginalmax-minproblemintoastandardmaximizationproblemandgiv

6、etheoptimalPAatrelayforagivensourcePAtomaximizetheinstantaneousrate.Finally,thesumtransmitpowerofeachgivensubcarrierpairisreallocatedtofurtherenhancethesystemcapacity.ThisthesisalsoinvestigatessubcarrierallocationproblemofrelayaidedOFDMsystemswithPFconstraintandproposesanefficientPFs

7、chedulingprioritybyusingtheuser’schannelconditionofpastschedulingtimeandcurrentschedulingtimemorecomprehensivelyanduniformlywhichcanbothmaximizethesystemtransmissionrateandenhancethesystemfairnessnolessthantraditionalones.Thesimulationresultsshowthevalidity.Thisthesisappliestherandom

8、geometrytheo