双选信道下OCDM系统低复杂度均衡宁晓燕宋禹良孙志国*孙晶晶(哈尔滨工程大学信息与通信工程学院哈尔滨150001)摘要：正交Chirp复用(OCDM)是近年来提出的一种新的多载波体系，通过菲涅尔变换，获得一组正交Chirp信号，实现了CSS的最大频谱效率。该文介绍了OCDM系统的基本原理，重点研究了OCDM系统的低复杂度均衡算法。双选信道下，传统的MMSE均衡算法性能下降，提出一种基于近似带状矩阵的阻尼LSQR算法，作为求解稀疏矩阵的最小二乘迭代算法。为了缓解快速时变信道中的ICI，提出一种基于近似带状矩阵的LSQR-BDFE算法，结合判决反馈均衡，通过LSQR算法迭代计算。仿真结果表明，双选信道下，OCDM系统比OFDM系统有着更好的BER性能，所提出的LSQR-BDFE算法和带状阻尼LSQR算法，比MMSE均衡算法有着性能优势。关键词：正交Chirp复用(OCDM)；菲涅尔变换；带状阻尼LSQR算法；LSQR-BDFE算法中图分类号：TN929文献标识码：A文章编号：1009-5896(2023)02-0516-08DOI:10.11999/JEIT211556LowComplexityEqualizationAlgorithmofOCDMSystemsinDoubly-SelectiveChannelsNINGXiaoyanSONGYuliangSUNZhiguoSUNJingjing(CollegeofInformationandCommunicationEngineering,HarbinEngineeringUniversity,Harbin150001,China)Abstract:OrthogonalChirpDivisionMultiplexing(OCDM)isanewmulti-carriersystemproposedinrecentyears.ThroughFresneltransform,asetoforthogonalChirpsignalsareobtained,whichachievethemaximumspectralefficiencyofCSS.Inthispaper,thebasicprincipleofOCDMsystemsisintroducedandthelowcomplexityequalizationalgorithmofOCDMsystemsisstudied.Indoubly-selectivechannels,theperformanceofthetraditionalMMSEequalizationalgorithmdeclines.ADamped-LSQRalgorithmisproposedbasedonapproximatebandedmatrix,asaleastsquareiterativealgorithmforsparsematrix.ToalleviateICIinrapidlytime-varyingchannels,anLSQR-BDFEalgorithmisproposedbasedonapproximatebandedmatrix.Combinedwithdecisionfeedbackequalization,LSQRalgorithmisusedforiterativecalculation.ThesimulationresultsshowthattheOCDMsystemhasbetterBERperformancethantheOFDMsystemunderdoubly-selectivechannels.TheLSQR-BDFEalgorithmandBandDamped-LSQRalgorithmhaveperformanceadvantagescomparedwiththeMMSEequalizationalgorithm.Keywords:OrthogonalChirpDivisionMulti...
