多用户MIMO系统中的机会波束成形技术

题（中、英文）目多用户MIMO系统中的机会波束成形技术OpportunisticBeam-formingforMU-MIMOSystems作者姓名袁利娟李勇朝教授工学提交论文日期二〇一三年一月通信与信息系统指导教师姓名、职称学科门类学科、专业代号分类号学号密级10701TN929.5公开1008120155摘要摘要多用户MIMO（MU-MIMO）传输是下一代无线通信关键技术之一，尤其在闭环MU-MIMO系统中，系统容量得到明显改善。虽然已有理论证明脏纸编码技术是一种昀优的预编码方案，可以昀大化MU-MIMO系统容量，但其复杂度过高。因此，设计低复杂度的MU-MIMO预编码方案成为关键。机会波束成形技术作为一种低反馈量的预编码方案，复杂度较低，而且当系统中用户数较多时，能够实现与脏纸预编码方案相同的渐进容量。机会波束成形技术的不足体现在当系统中的用户数较少时性能下降严重，论文针对这一问题展开了研究，主要工作包括1）分析了多权重的机会波束成形技术的性能，并对昀优权重数作了分析及仿真；2）将功率分配引入到机会波束成形技术中，在仿真基础上分析了两种功率分配方案的优缺点；3）将基于码本的迫零预编码与机会波束成形技术结合起来，通过仿真分析系统容量与反馈比特数的关系。此外，对多小区干扰受限场景下的机会波束形成技术进行了研究，给出了用户信干比的累积分布函数，并与基于轮询用户调度的特征波束成形技术进行了比较，结果表明，当小区间无协作且系统中用户数较多时，机会波束成形技术性能要优于特征波束成形。关键词：多天线机会波束成形系统容量机会调度AbstractAbstractAsoneofthekeytechnologiesfornextgenerationwirelesscommunication,Multi-userMIMO(MU-MIMO)transmissionisaneffectivewaytoincreasethecellthroughoutcapacity.Althoughtherehavebeentheoreticalproofthatdirtypapercodingtechnology,anoptimalpre-codingscheme,canmaximizethesystemcapacity,butit’scomputationalcomplexityistoohigh,sohowtodesignlow-complexityMU-MIMOprecodingschemeiscritical.Opportunisticbeamformingbasedonlowamountoffeedback,isoflowcomplexity,andwhentherearealargenumberofusersinthecell,itcanachievethesameasymptoticsum-capacityasdirtypaper.Thedisadvantageofopportunitybeamformingtechnologyisthatthereisseriousperformancedegradationwhentherearefewerusersinthecell.Tosolvethisproblem,thefollowingcontributionsaremadeinthisthesis：1)Multi-weightopportunisticbeamformingisusedandthenumberofoptimalweightsisdiscussedthroughtheoreticalanalysesandsimulationresults;2)Thepowerallocationisintroducedtotheopportunisticbeamformingtechnology,alsoadvantagesanddisadvantagesoftwopowerallocationschemesareconsideredthroughsimulations;3)zero-forcingbeamformingbasedoncodebookiscombinedwithopportunisticbeamformingtechnology,alsotherelationshipbetweensystemcapacityandthenumberoffeedbackbitsisanalyzedthroughsimulations.Inaddition,opportunisticbeamforminginthemulti-cellinterference-limitedscenariohasbeenstudied,andthecumulativedistributionfunctionoftheuser’sSIRisobtained.Theresultsshowthattheperformanceofopportunisticbeamforminginthisscenarioissuperiortoeigen-beamformingwhichbasedonround-robinschedulingwhenthereisnointer-cellcollaborationandfewerusersinthesystem.Keywords:MIMOOpportunisticbeam-formingSystemcapacityOpportunityscheduling目录目录第一章绪论.................................................................................................................11.1论文的研究背景.................................................................................................11.2多用户分集及用户调度.....................................................................................11.3机会波束成形简介.............................................................................................31.4机会波束成形技术研究现状.............................................................................41.5论文的研究内容和结构安排.............................................................................5第二章MIMO技术理论基础.....................................................................................72.1多用户MIMO(MU-MIMO)系统.......................................................................72.2多用户下行MIMO系统模型...........................................................................82.3多用户MIMO预编码技术...............................................................................92.4MIMO系统中波束成形技术.............................................................................92.5MIMO系统容量分析.......................................................................................102.5.1发射端未知信道状态信息.....................................................................112.5.2发射端已知信道状态信息.....................................................................122.6小结...................................................................................................................13第三章机会波束成形基础理论...............................................................................153.1机会波束成形的提出.......................................................................................153.2机会波束成形的演进.......................................................................................173.2.1由单波束到多波束.................................................................................173.2.1.1系统模型.......................................................................................173.2.1.2波束数目选择...............................................................................183.2.1.3仿真结果及分析...........................................................................213.2.2单接收天线到多接收天线.....................................................................223.2.2.1天线选择.......................................................................................223.2.2.2线性干扰消除...............................................................................233.2.2.3仿真结果及分析...........................................................................243.2.3单小区到多小区.....................................................................................253.2.3.1系统模型.......................................