简介:Awayofresolvingspreadingcodemismatchesinblindmultiuserdetectionwithaparticleswarmoptimization(PSO)approachisproposed.IthasbeenshownthatthePSOalgorithmincorporatingthelinearsystemofthedecorrelatingdetector,whichistermedasdecorrelatingPSO(DPSO),cansignificantlyimprovethebiterrorrate(BER)andthesystemcapacity.Asthecodemismatchoccurs,theoutputBERperformanceisvulnerabletodegradationforDPSO.Withablinddecorrelatingscheme,theproposedblindDPSO(BDPSO)offersmorerobustcapabilitiesoverexistingDPSOundercodemismatchscenarios.
简介:Toestimatethespreadingsequenceofthedirectsequencespreadspectrum(DSSS)signal,afastalgorithmbasedonmaximumlikelihoodfunctionisproposed,andthetheoreticalderivationofthealgorithmisprovided.Bysimplifyingtheobjectivefunctionofmaximumlikelihoodestimation,thealgorithmcanrealizesequencesynchronizationandsequenceestimationviaadaptiveiterationandslidingwindow.Sinceitavoidsthecorrelationmatrixcomputation,thealgorithmsignificantlyreducesthestoragerequirementandthecomputationcomplexity.Simulationsshowthatitisafastconvergentalgorithm,andcanperformwellinlowsignaltonoiseratio(SNR).