正交頻分復(fù)用（OFDM）系統(tǒng)及其均衡技術(shù)的研究.pdf

1、上海大學(xué)碩士學(xué)位論文正交頻分復(fù)用（OFDM）系統(tǒng)及其均衡技術(shù)的研究姓名：熊琴玲申請學(xué)位級別：碩士專業(yè)：通信與信息系統(tǒng)指導(dǎo)教師：鄒國良20040201AbstractTheforthgeneration(beyond3G)wirelesspersonalcommunicationsystemsareexpectedtoprovideubiquitoushighqualityandhidh—ratemobilemultimediatrans

2、missionAsahighefficiencymulti—carriertransmissiontechnologyOrthogonalFrequencyDivisionMultiplex(OFDM)isthecoretechnologyin4GmobilecOmmunfcationsystemandhasparticularpredominanceinthemultimediadatatransmissionSothebasicpr

3、inciples，systemconstructionandcharacIerislicsOfOFDMtechnologyarefirstintroduced1FFTandCyclicPrefixtechnologiesareemphasizedinOFDMsystemBasedonthesystemmodel，parameterandsystemsimulationflowchartMatlabiSintroducedforIhesi

4、mulationof0FDMsystemInaddition，Multiantennatechnologycaneffectivelyimprovethesystemcapacityandperformance；alsocanenhancethecoverscopeofnetworkandreliabilitySothenwesimulateandanalyzelheintegratedsystemofOFDMandMulti—Inpu

5、tMulti—OutputtechnologySecondlyMulticarrierCDMA(MCCDMA)iSoneoftheintegratedtechnologiesofOFDMandCDMAandkepttheadvantagesofOFDMandCDMAUsersareallowedtotransmifoneverycarrierthusobtainingmaximumfrequencydiversityEachuserIS

6、assignedaCDMAsignaturecode1nMC—CDMAtheusers’symbolsarespreadInfrenquecydomainandpriortomulticarriermosulationeachchipiStransmittedonadifferentchannelLaterwedesignachanneIestimationschemeinMIM0MC—CDMAsystemUSingthecharact

7、erofCDMA。TheresultofsimulationshowslhatlhisschemecangetgoodperformanceFinallyweanalyzelheInterSymboIinterference(ISI)andintercarrierinterference(ICI)inthesystemwhichhasthemulticarrierstructure(suchasOFDMandMCCDMA)Thenacc

8、ordingingtheinterferenceproblemswestudythefrndamentaIanddesigntechniqueofequalizerinOFDMsystemincludethefrequencydoaminequalizer(FEQ)andtimedomainequalizer(TEQ)ThegoalofFEQcarleffectivelycompensatethelinearitydistortiono

9、fsystemAndtheTEQwhichbeaFIRfilterjSusedtoshortentheeffectiveIengthofthechanneIimpulseresponse，BecauseaguardtimesequencecalledaCyclicPrefix(CP)，iSinsededbetweensymbolstoensurethatsamplesfromonesymboIdonotinterferewiththes

10、amplesofanothersymb01AndthelengthofCPiSdeterminedbythelengthoftheimpulseresponseoftheeffectivephysicalchannelUsingalongCPreducesthethroughofthesystem，andalsoimpropriatetheexcessfrequencyspectralandpowerToavoidusingaIongC

11、PaTEQ(shorttime—domainFIRfilter)iSusedtoshortentheeffectivechannelsimpuJseresponseWedesignaimprovedTEQtoshortthechannelimpulseresponseThusitcaneithershortentheguardinteEValmaintainingtheperformanceorimprovefheperformance