1、南京理工大學碩士學位論文無線OFDM系統(tǒng)中信道估計與均衡算法研究姓名：畢以峰申請學位級別：碩士專業(yè)：通信與信息系統(tǒng)指導教師：束鋒20070601碩上論文無線OFDM系統(tǒng)中信道估計≮均衡算法研究AbstractFuturewirelessscommunicationshowswiderbandwidthhighercarrigrfrequencyandhighermobilespeednleblockingtransmissiontech

2、niquesuchasOFDM(OrthogonalFrequencyDivisionMultiplexing)canefficientlycancelmultipathinterferencecausedbyincreasingsigrlalbandwidthachievehiglIbandwidthefficiencyandofferfrequencydomainequalizerwithlowcomplexityHighercar

3、rierfrequencyandfastermobilespeedleadstoICI(InterChannelInterference)WhentheNDS(NormalizedDopplerSpread)islargerthanO01。theconstantchannelmodelwillnotholdsoalinearornonlinearmodelfortheehannelisrequiredtosuppressICIInadd

4、itionquiteafewwirelesschannelsarcsparseIfthesparsity鋤befurtherexploitedtheeffectofchannelnoisecanbeefficientlyreducedTIlisimpliesthattheperformanceofthesystem啪besubstantiallyimprovedmpaperconsistsofthreepans：sparsechanne

5、lestimation，time—variantchannelestimationandtimevariouschannelequalization11掄maincontributionsofthepaperareasfollows：舢WeproposeajointchannelestimatorbasedonML(MaximumLikelihood)rulewhichcanestimateCIRandnoisevariancesimu

6、ltaneouslyBasedonthis。combiningtwoestimatedparaneterscanyieldathreshold—basedMLchannelestimatorcalledasIML(ImprovedML)BythesimulationintheHF／MFchannel，weobtain：IMLshows2dBSNRgaininBERperformanceoverthethetraditionalMLest

7、imatoritsperformanceisveryclosetothatoftheidealestimatorComparedwithotherestimators，theIMLhasthelowercomplexityandmoresimplestructureb1Weproposean醪tinlalorbasedonMLruleforO01NDSO1，whichuscstimedomainpilotsequenceThisesti

8、matorisimplemented8sfoLLows：firstwec吼gettheCIRestimationcorrespondingtothepilotsequence，thenweinterpolatetheCIRofdatasymbolsbysecondorderpolynomialinterpolation(SOPI)usingtheestimate洇CIRinthefirststepBythesimulationinthe

9、mobileurbanchannelitfollowsthattheperformanceoftheSOPIissupriort0linearinterpolationc)WeproposeanimplifiedZF(ZeroForcing)equalizer、ⅣitlllowercomplexityforthemediumtimevariantchannelTllisequalizercombinestheNuemarmseriesa

10、ndtheFFT／IFFTtechniquesoitc翹makeZFequalizerverysimpleBythesimulationinthemobileurbanchannel，theperformanceoftheequalizerproposedbyUSapproachesthatoforiginalZFequalizerKeywords：OFDM，Sparse，TimeVariantChannelEstimation，Sec