酉差分空時(shí)編碼技術(shù)研究

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1、摘要在無線通信鏈路中，空時(shí)編碼技術(shù)可大大提高數(shù)據(jù)傳輸速率，酉差分空時(shí)編碼作為空時(shí)編碼技術(shù)的一個(gè)分支，以其不需任何信道信息的特點(diǎn)而得到廣泛關(guān)注。本文簡(jiǎn)要介紹了空時(shí)編碼的發(fā)展和無線信道的特點(diǎn)，給出了無線信道衰落的仿真模型;綜合分析了分層空時(shí)碼、格形空時(shí)碼和分組空時(shí)碼三種空時(shí)編碼技術(shù)，它們都需要已知信道信息。在高速移動(dòng)的環(huán)境中或者當(dāng)發(fā)射天線數(shù)目很多時(shí)，獲得準(zhǔn)確的信道信息比較困難。酉空時(shí)編碼及酉差分空時(shí)編碼(DUSTC)都不需要信道信息，兩者相比，DUSTC不僅不需要任何信道信息，而且星座結(jié)構(gòu)簡(jiǎn)單，編譯碼易行，更加適

2、合于實(shí)際應(yīng)用。論文著重研究酉差分空時(shí)編碼技術(shù)，簡(jiǎn)要說明了酉空時(shí)編碼的信號(hào)形式及星座設(shè)計(jì)方法;分析了DUSTC的發(fā)送和接收公式，詳細(xì)研究了基于群論的DUSTC星座設(shè)計(jì)和搜索算法，給出了搜索結(jié)果，并進(jìn)行了Rayleigh衰落信道的仿真;分析了DUSTC的嚴(yán)格PEP和SEP的聯(lián)合界，給出了當(dāng)SNR值在不同的范圍時(shí)，DUSTC星座參數(shù)的選取準(zhǔn)則。最后，根據(jù)聯(lián)合界準(zhǔn)則搜索了群碼星座參數(shù)，給出了搜索結(jié)果，并進(jìn)行了Rayleigh衰落信道的仿真，仿真結(jié)果表明:聯(lián)合界準(zhǔn)則適用于中等大小SNR范圍，而非整數(shù)參數(shù)對(duì)星座性能影響不

3、大。關(guān)鍵詞:空時(shí)編碼(STC)，酉差分空時(shí)碼(DUSTC)，星座設(shè)計(jì)，成對(duì)錯(cuò)誤概率(PEP)，符號(hào)錯(cuò)誤概率(SEP)AbstractRecentadvancesincommunicationsacrossmultiple-antennawirelesscommuincationlinksshowthatspace-timecoding(STC)canhaveveryhighchannelcapacites.AnewclassofSTCcalledunitaryspace-timesignalsispropos

4、edthatiswelltailoredforRayleighflat-fadingchannelswhereneitherthetransmitterorthereceiverknowsthefadingcoeffients.Inthisthesis,webrieflyintroducethedevelopmentofSTC,andstudythecharacteristicandthesimulationsmodelsoftwokindsoffadingchannel.Wediscusssomedetai

5、lsaboutSTC,includinglayeredspace-timecoding,space-timetrelliscodingandspace-timeblockcoing.Space-timecodingcansupportveryhighdatarateswithlowerrorpropabilities,especiallywhenthewirelesschannelresponseisknownatthereceiver.However,theassumptionthatthechanneli

6、sknownisquestionableinarapidlychangingmobileenvironment,orwhenmultipletransmitterantennasareemployed.Unitaryspace-timecodesanddiferentialunitaryspace-timecodesdon'tneedanychannelinformation.Comparedwiththeunitaryspace-timecodes,DUSTCnotonlydosen'tneedanycha

7、nnelinformation,butalsohassimpleconstellationstructureandcoding-decodingalgorithm.Wediscusstheunitaryspace-timecodesbrieflyandstudythedetailsoftheDUSTC,includingthefundamentaldiferentialtransmissionandreceiverequation,theconstellationdesignbasedgrouptheory,

8、andparameterssearchingalgorithm.Theparameterssearchingandsimulationsresultsisproposed.ThenweanalyzetheexactPEPandunionboundofSEPoftheDUSTC.AndtheconclusionthatdiferentrangeofSNRsneedsdiferentsearchingc