简介:PN(Pseudo-Noise)codetrackingisthemostchallengingtaskinaDirectSequenceSpreadCodeDivisionMultiplexAccess(DS-CDMA)forcelluarmobilecommunicationsystems.Inthispaper,thegravityofenergywindows(GEW)trackingloopofthetimeandfrequencyuncertaintyofthereceivedsignalisinvestigated,andtheGEW’sanalyticalresultsinamulti-pathfadingchannelareintroduced.GEWtrackingloopexploitstheinherentmulti-pathdiversityofthechannel,andhasbetterperformancethansingle-pathonewhenworkinginmulti-pathfadingenvironment.
简介:TwoblindmultiuserdetectionalgorithmsforantennaarrayinCodeDivisionMultipleAccess(CDMA)systemwhichapplythelinearlyconstrainedconditiontotheLeastSquaresConstantModulusAlgorithm(LSCMA)areproposedinthispaper.OneistheLinearlyConstrainedLSCMA(LC-LSCMA),theotheristhePreprocessingLC-LSCMA(PLC-LSCMA).ThetwoalgorithmsarecomparedwiththeconventionalLSCMA.TheresultsshowthatthetwoalgorithmsproposedinthispaperaresuperiortotheconventionalLSCMAandthebestoneisPLC-LSCMA.
简介:Theparallelinterferencecancellationformulti-carrierDS-CDMA(whichistermedFDC-PIC)isproposedbyintegratingfrequencydiversitycombination.ThesimulationsaremadeoverFDC-PICwithrespecttodifferentdecisionways-hard,softandlineardecisions,respectively,andweconcludethatFDC-PICacquiressuperiorperformanceimprovementovercorrelationreceptionofmulti-carrierDSCDMA.Withanincreaseininterferencecancellationstages,thesystemperformanceisimprovedfurther.Theinitial2stagesbringaboutthemostdominantperformanceimprovement,butuptothe3rdstagethesystemperformanceisimprovedlittle.ItisalsoshownbythesimulationresultsthatFDC-PICwithsoftdecisionwouldexhibitthebestperformancewithahighimplementationcomplexity,whileFDC-PICwithlineardecisionacquiresperformancecomparabletothatofFDC-PICwithsoftdecisionwithareduced-complexityifthenumberoftheinterferencecancellationstagesisthesame,whichindicatesthatFDC-PICwithlineardecisionhasoptimalperformance/complexitytradeoffandthereforewillbesuitableforpracticalapplicationinfuture.