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1、西安電子科技大學(xué)碩士學(xué)位論文LTE下行鏈路關(guān)鍵技術(shù)的研究與實(shí)現(xiàn)姓名:馬曉慧申請(qǐng)學(xué)位級(jí)別:碩士專(zhuān)業(yè):通信與信息系統(tǒng)指導(dǎo)教師:張輝20090101摘要LTE(LongTermEvolution)是3GPP長(zhǎng)期演進(jìn)項(xiàng)目,兼容目前的3G通信系統(tǒng)并對(duì)3G演進(jìn)。它具有高傳輸速率、高傳輸質(zhì)量和高移動(dòng)性的特性。在復(fù)雜的移動(dòng)信道環(huán)境中,為了達(dá)到這些特性,信道估計(jì)是不可缺少的一環(huán)。而多入多出(MIMO)技術(shù)能夠突破無(wú)線(xiàn)頻率資源限制,大幅度地提高無(wú)線(xiàn)通信系統(tǒng)的頻偏效率,也被作為L(zhǎng)TE的一項(xiàng)核心技術(shù)來(lái)提高系統(tǒng)傳輸率。論文首先介紹LTE系統(tǒng)物理層的基本
2、概念,對(duì)LTE下行基帶處理流程各模塊進(jìn)行了深入研究。其次,研究了LTE下行基于導(dǎo)頻的信道估計(jì)技術(shù),詳細(xì)分析了LS信道估計(jì)算法、MMSE信道估計(jì)算法、二維線(xiàn)性?xún)?nèi)插算法和高斯內(nèi)插算法。然后,研究了LTE下行鏈路早的MIMO發(fā)射分集技術(shù),對(duì)MRC接收分集技術(shù)和SFTD發(fā)射分集技術(shù)進(jìn)行了深入研究和系統(tǒng)仿真。最后,結(jié)合考慮仿真結(jié)果和硬件實(shí)現(xiàn)復(fù)雜度,給出LTE下行鏈路發(fā)射端與接收端基帶處理的實(shí)現(xiàn)方案、LTE下行鏈路信道估計(jì)器的實(shí)現(xiàn)方案以及LTE下行鏈路解MIMO實(shí)現(xiàn)方案,并在DSP硬件開(kāi)發(fā)平臺(tái)上進(jìn)行了實(shí)現(xiàn)。關(guān)鍵詞:長(zhǎng)期演進(jìn)正交頻分復(fù)用信道
3、估計(jì)多入多出AbstractTheLTE(LongTermEvolution)schemewasproposedby3GPP,whichiscompatiblewithcurrent3Gtelecommunicationssystem.ChannelestimationplaysaquiteimportantroleintheLTEsystemwhichrequireshighdatarate,highqualityandhighmobility.Besides,Multiple—inputmultiple·output(MI
4、MO)technologycanbreakthroughtheconstraintoflimitedradiofrequencyresourceandsignificantlyincreasethespectralefficiencyofwirelesssystems.Hence,MIMOisalsoadoptedby3GPPasanimportantmethodtoenhancetheoveralltransmissionrate.AllofabovekeytechnologiesforLTEdownlinkareinves
5、tigatedinthisthesis.Firstly,thebasicknowledgeofPhysicalLayerinLTEsystemisintroduced.Wemainlyinvestigatethebasebandprocess,includingcyclicredundancycheck,tailbitingconvolutionalcoding,scrambling,ratematching,modulation,layermappingandprecoding.Then,aLTEdownlinkbaseba
6、ndprocessimplementationschemeisproposed,whichisrealizedonDSPplatform.Secondly,westudytheLTEdownlinkchannelestimationandinterpolationtechnology,andthenanalyzetheLSchannelestimation,MMSEchannelestimationalgorithm,two.dimensionallinearinterpolation,aswellasGaussianinte
7、rpolationalgorithm.Consideringthesimulationconclusionandthecomplexityofhardwareimplementation,aschemefordesigningtheLTEdownlinkchannelestimatorispresented,whichisalsoimplementedonDSPplatform.Finally,theLTEdownlinkMIMOtransmitdiversitytechniquesisresearched.Weinvesti
8、gatetheMRCreceivediversitytechniqueandSFTDtransmitdiversitytechnique,andthensimulatethemintheMatlabplatform.Accordingtothesimulationconclu