文档名：基于记忆多项式的Volterra混合均衡器设计与研究
摘要：[目的]发光二极管(LED)的非线性特性导致可见光通信(VLC)系统的误码率(BER)性能恶化,特别是在具有较高峰均功率比(PAPR)的光正交频分复用(O-OFDM)系统中.基于Volterra级数的单级均衡器可以处理LED非线性高阶失真,且延时较小.但是求解传统Volterra级数需要多重积分运算,基于Volterra级数的均衡器实现复杂度高,且单级均衡器存在误差累积,因此均衡抑制效果有限.[方法]首先,针对传统Volterra级数计算复杂度高的问题,只保留Volterra级数中各阶非线性项和内核系数的高阶幂级数项,提出了基于记忆多项式的Volterra级数(MPVS).相比于传统Volterra级数降低了计算复杂度,同时考虑了当前时刻的所有输入信号,提高了非线性系统建模的精度.然后,设计基于记忆多项式的Volterra(MPV)均衡器和基于记忆多项式的Volterra判决反馈均衡器(MPV-DFE),对于单级MPV-DFE,若判决部分一个码元判断错误,那么这种错误会连续成串出现,导致整个码元序列受到影响.文章提出将MPV和MPV-DFE两个非线性均衡器级联构成混合后均衡器(MPV+MPV-DFE).MPV均衡器对LED非线性失真信号一级均衡,可以抑制一部分非线性失真,从而减少MPV-DFE码元判断错误.再经过MPV-DFE二次均衡,可以更好地抑制残留的非线性失真.[结果]最后,采用蒙特卡洛BER仿真方法验证系统设计的有效性.结果表明:与单级MPV均衡器、线性级联非线性混合均衡器(LMS+MPV-DFE)相比,在4阶正交幅度调制(QAM)非对称限幅光OFDM(ACO-OFDM)系统BER为10-4时,所提混合均衡器分别可以获得大约7和2dB的信噪比增益.[结论]MPV均衡器实现简单,且将两级非线性均衡器级联设计混合均衡器可以更好地抑制LED非线性失真.
Abstract：[Objective]Thenon-linearcharacteristicsofLightEmittingDiodes(LEDs)contributetothedegradationofBitErrorRate(BER)performanceinVisibleLightCommunication(VLC)systems,particularlyinOpticalOrthogonalFrequencyDivisionMultiplexing(O-OFDM)systemswithhighPeak-to-AveragePowerRatio(PAPR).Asingle-stageequalizerbasedontheVolterraseriescanhandlethehigh-ordernon-lineardistortionsofLEDswithlowlatency.However,solvingthetraditionalVolt-erraseriesnecessitatesmultipleintegrationoperations,resultinginthehighimplementationcomplexityoftheVolterra-basedequalizer.Additionally,thesingle-stageequalizeraccumulateserrorswithlimitedperformanceimprovements.[Methods]Firstly,toaddresstheissueofhighcomputationalcomplexityinthetraditionalcalculationsoftheVolterraseries,apropositionismadetoretainonlythehigh-orderpowerseriestermsofthevariousnonlineartermsandkernelcoefficientswithintheVolterraseries.Thisapproach,knownastheMemoryPolynomial-basedVolterraSeries(MPVS),notonlyreducesthecomputationalcomplexitycomparedtothetraditionalVolterraseriesbutalsoenhancestheaccuracyofnonlinearsystemmodelingbyconsideringallinputsig-nalsatthecurrentmoment.Subsequently,thedesignofchannelequalizerconsiderstheMemoryPolynomial-basedVolterra(MPV)equalizerandtheMemoryPolynomial-basedVolterraDecisionFeedbackEqualizer(MPV-DFE).Forasingle-stageMPV-DFE,ifanerroroccursinthedecisionpartleadingtoanincorrectsymboldecoding,thiserrortendstomanifestasaconsec-utiveseriesoferrors,therebyimpactingtheentiresymbolsequence.Tomitigatethis,aproposalismadetocascadethetwonon-linearequalizers,MPVandMPV-DFE,formingahybridequalizercalledMPV+MPV-DFE.TheMPVequalizerperformsaprimaryequalizationontheLED'snonlineardistortionsignal,effectivelysuppressingaportionofthenon-lineardistortionsandtherebyreducingsymboldecodingerrorsintheMPV-DFE.Subsequently,asecondaryequalizationiscarriedoutbytheMPV-DFE,leadingtoimprovedsuppressionofresidualnonlineardistortions.[Results]Finally,theeffectivenessofthesystemdesignwasvalidatedusingMonteCarlosimulationtoanalyzetheBER.Theresultsdemonstratethatcomparedtothesingle-stageMPVequalizerandthelinear-cascadenonlinearhybridequalizer(LMS+MPV-DFE),theproposedhybridequalizerachievesapproxi-mately7dBand2dBSignal-to-NoiseRatio(SNR)gains,respectively,ina4QuadratureAmplitudeModulation(QAM)-mod-ulatedAsymmetricallyClippedOpticalOFDM(ACO-OFDM)systemataBERof10-4.[Conclusion]Inconclusion,theimple-mentationoftheMPVequalizerisstraightforward,andthecascadeddesignofthetwo-stagenonlinearequalizersasahybridequalizerenablesbettermitigationoftheLED'snonlinearity.
作者：贾科军 雷蕾 蔺莹 余彩虹 Author：JIAKejun LEILei LINYing YUCaihong
作者单位：兰州理工大学计算机与通信学院,兰州730050福建工程学院电子电气与物理学院,福州366000
刊名：光通信研究 ISTICPKU
Journal：StudyonOpticalCommunications
年，卷(期)：2024, (3)
分类号：TN929.12
关键词：可见光通信 发光二极管非线性 沃尔泰拉级数 混合后均衡器
Keywords：VLC LEDnonlinear Volterraseries hybridpostequalizer
机标分类号：TN929.1TP277TN707
在线出版日期：2024年6月6日
基金项目：国家自然科学基金，甘肃省科技计划资助项目，甘肃省科技计划资助项目，甘肃省科技计划资助项目，甘肃省科技计划资助项目，兰州理工大学博士科研启动项目基于记忆多项式的Volterra混合均衡器设计与研究[
期刊论文] 光通信研究--2024, (3)贾科军 雷蕾 蔺莹 余彩虹[目的]发光二极管(LED)的非线性特性导致可见光通信(VLC)系统的误码率(BER)性能恶化,特别是在具有较高峰均功率比(PAPR)的光正交频分复用(O-OFDM)系统中.基于Volterra级数的单级均衡器可以处理LED非线性高阶失真,且延时...参考文献和引证文献
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