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ID:37355213
大小:2.44 MB
页数:81页
时间:2019-05-22
《酉差分空时编码技术研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、摘要在无线通信链路中,空时编码技术可大大提高数据传输速率,酉差分空时编码作为空时编码技术的一个分支,以其不需任何信道信息的特点而得到广泛关注。本文简要介绍了空时编码的发展和无线信道的特点,给出了无线信道衰落的仿真模型;综合分析了分层空时码、格形空时码和分组空时码三种空时编码技术,它们都需要已知信道信息。在高速移动的环境中或者当发射天线数目很多时,获得准确的信道信息比较困难。酉空时编码及酉差分空时编码(DUSTC)都不需要信道信息,两者相比,DUSTC不仅不需要任何信道信息,而且星座结构简单,编译码易行,更加适
2、合于实际应用。论文着重研究酉差分空时编码技术,简要说明了酉空时编码的信号形式及星座设计方法;分析了DUSTC的发送和接收公式,详细研究了基于群论的DUSTC星座设计和搜索算法,给出了搜索结果,并进行了Rayleigh衰落信道的仿真;分析了DUSTC的严格PEP和SEP的联合界,给出了当SNR值在不同的范围时,DUSTC星座参数的选取准则。最后,根据联合界准则搜索了群码星座参数,给出了搜索结果,并进行了Rayleigh衰落信道的仿真,仿真结果表明:联合界准则适用于中等大小SNR范围,而非整数参数对星座性能影响不
3、大。关键词:空时编码(STC),酉差分空时码(DUSTC),星座设计,成对错误概率(PEP),符号错误概率(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
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