Cpm OFDM 系统中 NLM 交织方案的性能分析(IJWMT-V9-N1-2)

I.J.WirelessandMicrowaveTechnologies,2019,1,11-22PublishedOnlineJanuary2019inMECS()DOI:10.5815/ijwmt.2019.01.02Availableonlineat:20August2018;Accepted:22October2018;Published:08January2019AbstractANewLogisticMapinterleavingisthemostcommonmethodforcontinuousphasemodulationbasedorthogonalfrequencydivisionmultiplexing(CPM-OFDM)systemoverafadingchannel.Theselectionofagoodinterleaverhavingtoexpressinorderthattheinterleaversareweaklycorrelated.Interleaverdoesn’tinvolvemassivememorytoreserveitandamassivebandwidthtocommunicateinthemidstofthetransmitterandthereceiver,andneedtobesimpletoproduce.Anefficientchaoticmapsrandomization(CMR)generatesscrambleduncorrelatedrandomizeddatacangreatlyimprovedtheperformanceofCPM-OFDMsystemandimprovedsymbolerrorrate(SER)couldbeattained.Inthisstudy,adviseanewone-dimensionalchaoticmap,theNewLogisticMap(NLM).Encryptioniscarriedoutwithlogisticmapevenasachaoticlogisticmapinterleavingprocessisusedtoboosttheimmunitytonoiseandfadingincommunicationchannel.Furthermore,aevaluationbetweenNLMinterleavingandrandominterleavingisperformedintermsofbiterrorrate(BER).SimulationresultsshowsthatthedatatransmissionoverwirelesschannelusingproposeNLMinterleavingismoreimmunetofadingandnoiseandgetbettertheperformanceofCPM-OFDMsystem.IndexTerms:Chaoticsystem,Logisticmap,Interleaver,OFDM,constantenvelope,RandomInterleaving©2019PublishedbyMECSPublisher.Selectionand/orpeerreviewunderresponsibilityoftheResearchAssociationofModernEducationandComputerScience1.IntroductionThedemandoffutureandcurrentwirelesscommunicationishighqualityservices,improvedcapacity,requirehigherdataratetransmissionandtosustainwidebandwirelessservicessimilartohighdefinition(HD)TV,videoconferencing,mobilevideophones,andrapidinternetaccess.Thoughthereexist*Correspondingauthor.Tel.:E-mailaddress:[e-mail],[e-mail]12PerformanceAnalysisofNLMInterleavingSchemeforCPMOFDMSystemdemandingsituationsforthesesystemslikefrequencyselectivechannelthatisreceivedbymulti-pathenvironment.Thebandwidthofsignalinbroadbandcellularwirelesssystemisnormallygobeyondthecoherencebandwidthofthemultipathchannel.Thereforefrequencyselectivefadingresultsandleadstointer-symbolinterferencesoccursthatbadlyhaveaneffectonsystemperformance[1].OFDMistakenanaccountofthemosteffectivemulticarriertransmission(MCT)techniquesinfavourofmobilecommunications,asitgivesamassiveimmunityinordertomultipathfadingaswellasimpulsivenoise,alsoremovestherequirementforcomplexequalizers[2].Inspiteofalloftheadvantages,therearesomedrawbacksofOFDM.ThemajorlimitationsofOFDMsystemsarehighpeakaveragepowerratio(PAPR).Asthenumberofsubcarriersincreases,PAPRofOFDMsignalsincreases.Signalsaretransmittedovernon-linearpoweramplifierbecauseofhighPAPR,harshsignaldistortionwillhappen.Asaresult,powerbackoffwithlinearpoweramplifierisrequiredforOFDMsystems[3].Thesystemundergofromspectralbroadening,intermodulationdistortion,withoutsufficientpowerbackoff,and,therefore,performancedegradation.Thisissuemightbedecreasedbyincreasingthebackoff,butthiscausetohappendecreasedpoweramplifier(PA)efficiency.Duetolimitedpowerresourcesthisisparticularlyanissueformobilebattery-powereddevices.Minimizingitseffectfitinconcerntobothcommercialandmilitaryapplications[4]SeveralapproachhavealreadybeenplannedtoworkoutthePAPRdifficultylikeclippingandfiltering,ToneInjection(TI),coding,ToneReservation,andalsomultiplesignalrepresentationtechniques,forexamplethePartialTransmitSequence(PTS),theinterleavingapproach,andtheselectivemapping.TheseapproachesareusedtosolvethePAPRproblemsandincreasethesignaltransmittedpower,computationalcomplexityandachievebetterbiterrorrate(BER).AnanothermethodtojustifyingthePAPRdifficultyisbasedonsignaltransformations[5]Incellularcommunication,theideaofContinuousPhaseModulationisusedduetoithasaconstantenvelope(CE)thathasessentialforeffectivepowertransmissionandhavethecapabilitytotakeadvantageofthediversityofmultipathchannelresultinginupgradingthebiterrorrate.ThebenefitofthePhaseModulator(PM)transformsonethetransformedsignalhastheminimumattainablePAPR(i.e.0dB).Thesesignalsmaywellbeamplifiedalongnominalpowerbackoff,andthat:1)boosttheeffectivenessofpoweramplifier,alongwith2)probablyincreasesschemerange,therefore,additionalsignalpowerispropagatedtowardthechannel.PhasemodulationisdrawingattentionforwirelesstelecommunicationsduetotheCEofyourgeneratedsignals,andthat’sneededforefficientpowertransmitters,andhasacapacitytotakeadvantageofthediversityofyourmulti-pathchannel,whicheverisdesirabletorecovertheBitErrorRateperformance.IntheeraofInternetgrowingandmultimediaforexamplevideo,audiosignalsandimagearesimplytransmittedfromaserviceprovidertoaconsumer,thisofferanimmensepayoffforenhancementofmultimedia,E-c