寬帶CDMA移動通信中的聯(lián)合檢測技術(shù).pdf

1、東南大學(xué)博士學(xué)位論文寬帶CDMA移動通信中的聯(lián)合檢測技術(shù)姓名：彭岳星申請學(xué)位級別：博士專業(yè)：信號與信息系統(tǒng)指導(dǎo)教師：吳鎮(zhèn)揚20040501查墮查堂墮蘭堡蘭二—型型璺墮———————————————一AbstractT11eDerformaneeandcapacityofwidebandcodedivisionmultipleaccess(CDMA)systemsat“esevetelvlimitedbymultipleaccessint

2、erference(MAI)，intersymbolinterference(ISI)andfrequencyselectivetime，varying(TV)fadingofmobilechannelsinducedbymulti‘patheffect，Dopplereffectandnonorthogonalspread—spectrumcodesbetweentheactiveusersMulti—userdetection(MU

3、D)，InterferencesuppressionandchannelestimationarethekeytechniquesforwidebandCDMAmobilecommunicationsystemsThisdissertationconcentratesontheiterativerealizationofMUDinterferencesuppressionandchannelestimationfortheuplinko

4、fmobilecommunicationsystemsoverfrequencyselectivetimevaryingfadingchannels，anditincludes：●Proposedanequivalentsynchronoussuccessiveinterferencecanceller：classicsuccessiveinterferencecanceller(sic)mustrankusers’signalsind

5、escendingorderofreceivedpowers，weakusersgetmoreinterferencecancellation(IC)gainsthanstrongones，andSIChaspoorabilitytesistnearfareffectTheproposed1Cneednotsortusersbyreceivedpowers，andorthogonalizethespreadspectrumcodeseq

6、uencebyGram—Schmitzmethod，thusitcanimprovetheabilitytesistnearfareffect●Designedasemi—blinditerativeestimatorforfrequency—selectivefadingchannelswithlargeDopplershift：Semi—blindchannelestimatorhasbeRergeneralperformancet

7、hannon—blindandblindchannelestimators，statespacemethodusingKalmanFilterverysuitsfortracingTVchannelsConventionalstatespacemethodconstructsstateequationbyARmodelwithconstantcoefficientsItcaneffectivelytracktime—invariable

8、orslowlyTVchannels，whenchannelshavelargeDopplershift，thismethodwilllosetrackofTVchannelsSoweconstructthestateequationbyARequationwithTVCOC塌cientsthatareestimatedthroughRecursiveLeastSquare(ProS)withadaptivememoryandconst

9、ructobservationequationbyFIRequationwithTVtoe茄cientsthatareestimatedthroughKalmanFilterandaidedbyinformationsymbolsestimatedbyMMSEequalizeriterativeestimatorforfrequency—selectivefadingchannelswithIargeDopplershiftiseffi

10、cientlytraced●Proposedaniterativemulti—userdetector(MUD)combiningchanneltrackerandmodifiedpartialparallelinterferencocanceller(PPIe)：parallelinterferengecanceller(PIC、willintroducedoubleMAIiftentativedecisioniswrongthusP

11、PICismorepopularTheoptimumweightsofPPlCaregotbycomputationintensivemethodsuchaseigenvaIuecomputationorMMSEmethod，whichisoflittlepracticabilitywhenthecodesisrandomandsystemsisoverTVchannelsBecausetheweightsaredeterminedby

12、thecorrelationofcodesequenceandestimationerrorofchannels，whichcanbenearlydeterminedbysystemloadfactogwedeterminethesuboptimumweightsbysystemloadfactorthroughsimulations，andsubstitutetheharddecisionsymbolfunctionbysoftdec

13、isionhyperbolictangentfunctiontodecreasetheriskoferrordecision，●Proposedaturboequalizerandaturbomulti—userdetector：thereasonofturbocodeattai|1inEShannoncapacityboundsisthe“turboprinciple”indecoding，whichmeanssoftinformat

14、iontransferanditerativeupdatingbetweenthememberdecodersUnderthe‘‘turboprinciple”，turboequalizerwhichcombinesequalizerandchanneldecodegandturboMUD，whichcombinesMUDandchanneldecoder，cangreatlyincreasetheperformanceofsystem