58相干光通信若干关键技术的研究

华中科技大学硕士学位论文相干光通信若干关键技术的研究姓名：王修阁申请学位级别：硕士专业：通信与信息系统指导教师：汪小燕;董燕20080602IIBPSKFFTVVLMSMatlabIIIIAbstractAccordingtothedifferenceofcoherentreceivers,satellitelasercommunicationsys-temscanbedividedtocoherentandnon-coherentopticalcommunications.Earlysatellitelasercommunicationsystemshaveadoptednon-coherentopticalcommunicationsystemsthatsatisfyalow-bit-ratecommunicationrequest,butthepoweroftransmitterandsensi-tivityofreceiverlimitthecommunicationrate.Whilecoherentopticalcommunicationsystemhasgreatadvantagesinthelong-distance,high-speedcommunicationsandbecomethemajormeansofsatellitelasercommunications.Coherentopticalcommunicationsystemhasmanykeytechnologiestoberesolved,suchasDopplerfrequencyshiftcausedbytherelativelyrapidmovementofcommunica-tionterminalsmakescarriersynchronizationworse.Thephasenoiseoflasermakesitdif-ficultforreceivertodemodulatethesignal.Atmosphericturbulencecausestheoutageprobabilityincrease.Inthisthesis,wehaveproposedsomealgorithmscorrespondingtotheseissues:Dopplerfrequencyshiftcompensationalgorithm,phasenoisereductionalgo-rithm,multi-beamtechnology.ThisthesischoosesBPSKasthemodulationofthecoherentopticalcommunicationandsimulatesitsbiterrorrate.AgainsttheimpactofDopplerfrequencyshift,ThisthesisproposedFFTandV&Valgorithmandleast-squaresestimationalgorithm.Inordertore-ducetheimpactofphasenoise,constrainedLMSalgorithmisproposed.Toovercomeat-mosphericturbulencethatcausedoutageprobabilityincrease,thispaperhasintroducedamulti-beamtechnology,andstudiedtheequalgaincombinationandoptimalcombinationthateffectivelyreducetheoutageprobability.Basedonthetheoreticalanalysis,thisthesishasallthealgorithmssimulatedbyMat-lab,respectively.Fromtheresults,allthealgorithmsproposedbythisthesishavesolvedtheaboveproblemseffectively,achievingtheaimofimprovingtheperformanceofco-IIIIIIherentopticalcommunicationsystem.Thisthesishasprovidedtheoreticalsupportforthedesignofcoherentopticalcommunicationsystem.Keyword:Coherentopticalcommunication;ChannelEncoding;Dopplershiftcompensa-tion;Phasenoise;Multi-beam________“√”1111.1[1]10-20dB[2][3][4][5][6][7]221.2/IM/DD[8]1.1[9]1.2331.11.290IM/DD[10][11]1990,[12],,YAG,YAG,(BPSK)/Costas,140Mbps,10-91996,44(SROIL),(LEO)(GEO):3.5cm1.5Gbps10-610kg,40W1550nmSILEX[13]ContravesOPTELBPSK[14]OPTEL-022000km1.5GbpsOPTEL-2525000km1.5GbpsOPTEL-808000km2.5GbpsTerraSAR-XTerraSAR-X(LTC)5.625Gbps(24*255Mbps)TSXLCT10-96000km8Gbps,20000km1Gbps0.5W72000km500Mbps5-7WBPSK55[15][16][17][18]FFTVV[19]ADLMS[20](Caltch)JamesLeshKeithWilson1995GOLD[21]I.I.KimTerraLinkTM8-155[22]661.3BPSKBPSKFFTVVLMS772BPSK[23][24]BPSKBPSKBPSK2.1BPSKBPSKBPSK2.1.1BPSKBPSKcos()()cos()()sin()1()cos()()cos()()sin()0cccsccccscAtnttnttytAtnttnttωωωωωω+−=−+−2.1.1()1()()0ccAntxtAnt+=−+()xt12121()()exp22nnxApxσπσ−=−02021()()exp22nnxApxσπσ+=−2.100x10x010(1)(0)eeePPPPP=+1()px0()px10(0)(0)eePxPx=001()[(1)(0)]()2eePPxPPdxerfcr∞=+=∫2.1.288-4-3-2-10123400.050.10.150.20.250.30.350.4xp(x)2.1BPSKBPSK2.205101510-1610-1410-1210-1010-810-610-410-2100(dB)2.2BPSKBPSK10dB10-6BPSK992.1.2BPSK1(,)(21,21)mmnkm=−−−732RSRSReed-SolomonRSBCHRSm(,)nk21mn=−k2nkt−=021dt=+RSnRS2mRSRS73RS31995P.Eliasnkmk(,,)nkm(312)poly2trellis(7,[171133],171)10102.32.32.42.42.5+++0iC1iC2iC20im−10im−0immiC1/1010/0001/1110/0010/1010/0111/1000/010S0(00)S3(11)S2(10)S1(01)()T=0T2T3T4T5T6T1/1110/0111/1101/1000/0100/0011/11011112.54TurboTurbo[25][26][27]Turbo2.6122.6Turbo10100011100111001110001014320(1)0PM=0(2)PM=∞0(3)PM=∞0(3)PM=∞1(1)2PM=1(2)PM=∞1(3)1PM=1(4)PM=∞2(1)5PM=2(2)2PM=2(3)2PM=2(4)2PM=3(1)3PM=3(2)2PM=3(3)4PM=3(4)5PM=R1=110R2=111R3=0111212TurboTurboTurbo2.7log(map)222222222112Le21L(K)Le121py2pysy2.7TurboBPSK2.1.3BPSKMatlabSimulinkRSCMatlabTurbo2.81313Matlab01744bit3bit7bit7bit4bitRSTurboCBPSKBPSK2.8BPSK2.92.9BPSK1414TurboBPSK5dB10-2Turbo5dB10-5BPSK2.2BPSK[28][29]0exp[()]SSSEAjtωφ=−+SA0ωSφexp[()]LOLOLOLOEAjtωφ=−+LOALOωLOφAPD()2cos()SLOSLOIFSLOPtPPPPωφφ=+++−IFω0LOωω−IFω0ωLOω0IFω=()()2cos()SLOSLOSLOItRPPRPPφφ=++−R0SLOφφ−=2PSLOIRPP=LOω0ωIFωAPDIRP=2.2.11515()()2cos()SLOSLOIFsLOItRPPRPPtωφφ=+++−2.2.1LOPSP()2cos()SLOIFsLOItRPPtωφφ=+−2.2.22.2.2LOP2PSLOIRPP=3dB3dB3dB3dB222()sAindqMFRPIfσ=+∆f∆qAFAPDdILR24(/)TBLnkTRFfσ=∆2.2.32222222222()acSLOSLOsTLOdTIRPPRPPSNRqRPIfσσσσ===++∆+2.2.3/2fB∆=BLOPLOP2/(2)TqRfσ∆16162sσ2Tσ2.3.4SSRPPSNRqfhvfη==∆∆(2.3.4)SNRPNSPPNSPPNhvB=B/2fB∆=2PSNRNη=24PSNRNη=910BER−=1000PN=3dB2.3BPSK[30][31]17171243BBATIABBATIABBAAGCBBABBABBABBAPINd:YAG(LO)In-PhaseQuadrature2.152.1590I[](1)exp()1()1()SISsEPjtatjbtαφαα=−+−+−2.3.1SP()stφαI()atQ()bt()()()2sSNtdttπφφ=+()dt+1-1()SNtφIexp()()2LILLNcEPjttπαφφ=++LP()LNtφ()()tcvcoctGvtdtφ−∞=∫vcoG()cvt181811()2SILIEEE=+2.3.221()2SILIEEE=−2.3.3I1*11122[(1)2(1)()2cos(()())22(1)()sin(()())2(1)(()())2(1)cos(()())222(1)()cos(())22(1)SSSNSSNLSLeLiREERPatPdttbtPdttatbtPPPdttPattααπφπαφααππααφπααθαα=⋅=−+−⋅++−++−+++−+−+−++−1()sin(())]()2LPbttntπθ++2.3.42*22222[(1)2(1)()2cos(()())22(1)()sin(()())2(1)(()())2(1)cos(()())222(1)()cos(())22(1)SSSNSSNLSLeLiREERPatPdttbtPdttatbtPPPdttPattααπφπαφααππααφπααθαα=⋅=−+−⋅++−++−+++−+−−