多用户ofdm系统中自适应资源分配算法.研究

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1、华中科技大学硕士学位论文AbstractThemainprobleminbroadbandsystemsisInterSymbolInterference(ISI)duetomultipathfading.OrthogonalFrequencyDivisionMultiplexing(OFDM)techniquehasattractedtheattentionofmanypeople,becauseitcancombatmultipathfadingandhashighband-widthefficiency.StaticTDMAorFDMAwasadoptedinatra

2、ditionalmultiuserOFDMsystem.Asaresult,thebestsubcarrierforoneusermaybeonlyusedforfractionaltimeorhasneverbeenusedatall.Inordertosolvetheproblemsabove,wecanmakeuseofthemulticarrierstructureofOFDMsystems,alteringthetransmitparametersaccordingtotheinstantaneousstatusofeachsubchannelandallocat

3、ingdifferentnumberofbitsordifferentamountofpowertoeachsubcarrier.Inthisway,theperformanceofthesystemisoptimized.WhilethistechniqueisextendedtomultiuserOFDMsystems,wecanallocatesubcarrierstousersaccordingtotheinstantaneousstatusofsubchannels,sothattheradioresourceisallocatedtousersfairlyand

4、effectively.MostexistingworkonadaptiveallocationofsubcarriersandpowerinmultiuserOFDMsystemshasfocusedonhomogeneoustrafficconsistingofdelay-constraineddata(guaranteedservice)ordelay-tolerantdata(best-effortservice)only.Inthiswork,weinvestigatetheresourceallocationprobleminaheterogeneousmult

5、iuserOFDMsystemwithbothdelay-sensitive(DS)andno-delay-sensitive(NDS)traffic.Theobjectiveistomaximizethesum-rateofalltheuserswithNDStrafficwhilemaintainingguaranteedratesfortheDStrafficunderatotaltransmissionpowerconstraint.Aniterativealgorithmisproposedtocomputetheoptimalsolutionsnumerical

6、ly.Alow-complexitysuboptimalallocationalgorithmisalsopresented.SimulationexperimentsareconductedtoevaluatetheperformanceoftheproposedalgorithmsintermsoftransmissionpowerconstraintandachievabletransmissionratepairsforDSandNDStraffic.Theresearchofthispaperoffersanewresearchideasandtheoretica

7、lreferenceontheradioresourcemanagementstrategyforfuturemobilecommunicationsystems.Keywords:OrthogonalFrequencyDivisionMultiplexing(OFDM),Multiusersystem,AdaptiveAlgorithm,SubcarrierAllocation,PowerAllocationII华中科技大学硕士学位论文目录摘要...................................