mb-ofdm系统抗窄带干扰技术的.研究

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1、王海洋：MB．oFDM系统抗窄带干扰技术的研究3ABSTRACTThemulti-bandorthogonalf-requency-diVisionmultiplexingultra-wideband(MB-OFDMUWB)systemcombiningOFDMwithfrequencyhoppingisapromisingcandidateforthefutureshort-rangemobilecommunicationsystems．Thenarrow-bandinterferencesuppre

2、ssingand嬲ti．multipathfadingtechniquesintheMB-OFDMsystemsarestudiedinthisthesis．Themaincontentofthethesisareasfollowing：BasedonthetraditionalinterfcrencesuppressingOFDM(IS—OFDM)UWBsystem，anewUWBsystemisproposedbyusingthecarriergrounpingwayforcombatingthen

3、arrow-bandinterferences，whichexistinthespectrumrangeofaUWBsignal．IntheproposedIS-OFDMUWBsystem，thecodedbitstreamsarespreadoVerthesub—carriersthroughmakingfulluseofthefIrequencydiVersityacrossallthesub-carriers．ThisincreasesdiVersitygainandprovidestherobu

4、stnesstonarrowbandinterferenceforMB—OFDMUWBsystem．And，theValueofgroupingnumbermaybeoptimizedintermsofthechannelenvironmentforenhancingtheperformanceofthesystemmoreeffbctively．Furthermore，thebinarysignaturesequenceswithminimumtotalsquaredcorrelation(TSC)a

5、reusedtoshapethespectrumofthetransmittedsignal．Boththeoreticanalysisandnumericalresultsobtainedfromsimulationsshowthatthismethodcouldfurtherpromotetherobustnessofthesystemtonarrow-bandinterference．ConvolutionalcodingandbitinterleaVingareenlployedtoexploi

6、tthediversityintheMB-OFDMUWBsystem，buttheyarenotsuitableforthesystemwithahighdatarate．ThediVersitygainofthesystemwithhighrate，couldbeimprovedbyutilizingspreadingtransform．HoweVer，themultipathcomponentinachannelwouldnotbeusedefncientlywithacommonorthogona

7、lspreadingmatrix．Therefore，anewMB—OFDMUWBsystembasedonahigherorderrotationspreadingmatrixisproposedtosuppressthebad4扬州大学硕士论文eff．ects0fnarrowbandinterference0ntheMB-OFDMUWBsystem．’I'headVantageofthisnewspreadingmatrixoVermoretraditionalspreadingmatrixisit

8、snexibilityindeterminingdifferentstructuresofmatrixeswiththesimpleanglerotation．ThesematrixescanadVancethecorrelationbetweenthetransmittedsymbolsandimproVetheutilizationrateofthemultipathcomponentinUWBchannel．And，thedivers