TTCM與CPM級聯(lián)系統(tǒng)聯(lián)合檢測譯碼算法研究.pdf

1、西安電子科技大學碩士學位論文TTCM與CPM級聯(lián)系統(tǒng)聯(lián)合檢測譯碼算法研究姓名：黎昞申請學位級別：碩士專業(yè)：通信與信息系統(tǒng)指導教師：白寶明20090101AbstractAbstractCPM(Continuous—PhaseModulation)，asakindofconstantenvelopmodulationscheme，itisbeRerthanthetraditionalmemorylessmodulationschemesi

2、nthesensethatitiSnotsensitivetothenonlinearclassCamplifierwhichmeans2～4dBgaincallbeobtainedcomparedtothoseuseAclass(orBclass)amplifierBecauseofthese，itiswidelyusedinthecommunicationsystemssuchassatellite，mobileradioandst

3、ationThisPaDermainlydealswiththeconcatenatedcodedmodulationbasedonCPMGenerallyspeaking，theperformanceofspecifiedCPMschemeiscloselyrelatedtothemodulationordermodulationindex，memorylengthandpulseshapeToachieveenergyefficie

4、ncyandbandefficiencybyemployingsmallmodulatorindexwilldegradetheperformanceintermofBERTosolvethisproblem，weproposeaconcatenatedsystemusingCPMandTurboTCMastheinnercodeandoutercodeindependentlydemodulationanddecodingrunsit

5、erarivelyTheTurboTCMhasallighcoderateaswellasgoodperformance，suchthattheentiresystemmaintainsnarrowbandandhighinformationrateConsideringthatinpracticalscene，noncoherentdetectionofdigitalsignalsisanattractivestrategyinsit

6、uationwherecarrierphaserecoveryisdifficultMostofthedrawbacksofphase—lockedloop(PLL)circuitsusedtOapproximatelyimplementcoherentdetection，maybeavoidedbynoncoherentdetectorsSpecificallMtypicalproblemsofPLLssuchasfalse—lock

7、s，phase—slips，orlossesoflockcausedbyseverefadingDopplershifts，phasenoise，oroscillatorfrequencyinstabilitiesaresimplybypassedByemployingOsbsme—Luntzreceiverthenoncoherentdetectorwecanbreakthe3dBgapbetweencoherentandnoncoh

8、erentdetectionComparedtomostofthecurrentCPMconcatenatedsystems，theschemeproposedinthispaperoperateson8arysymbollevel，narrowbandandhi曲ratesWeinvestigatedtheimpactofmodulationordermodulationindexandpulseshapetothesystemand