简介:Thesingle-carrierblocktransmission(SCBT),a.k.a.,single-carrierfrequency-domainequalization(SC-FDE),isbeingconsideredasanoptiontechniqueforthewirelesspersonalareanetwork(WPAN)operatingat60GHz.Itisfoundthatforresidentialenvironment,innon-line-of-sight(NLOS)multi-pathchannels,theSCBTismuchmoreeffectivetocombattheinter-symbolinterference(ISI)comparedwithorthogonalfrequencydivisionmultiplexing(OFDM).Low-densityparity-check(LDPC)codesareaclassoflinearblockcodeswhichprovidenearcapacityperformanceonalargecollectionofdatatransmissionandstoragechannelswhilesimultaneouslyadmittingimplementabledecoders.TofacilitateusingLDPCcodesforSCBTsystem,anewlog-likelihoodratio(LLR)calculationmethodisproposedbasedonpilotsymbols(PS).GolaySequenceswhosesumautocorrelationhasauniquepeakandzerosidelobeareusedforcreatingthePS.ThepositionandlengthofthePSarenotfixedinthedatablocks.ThesimulationresultsshowthattheproposedmethodcansignificantlyimprovetheLDPCdecodingperformanceinSCBTsystem.Thisisverypromisingtosupportultrahigh-data-ratewirelesstransmission.
简介:<正>市场研究机构ABIResearch的最新报告指出,虽然在2008年与2009年遭遇经济衰退,RFID市场在2010年复原状况良好,成长率略高于14%,达到53亿美元;若将汽车防盗(automobileimmobilization)硬件系统也加计在内,该市场
简介:Anovelapproachtogenerate60GHzopticalcarriersuppression(OCS)millimeter-wave(mm-wave)signalbasedonthesaturatedopticalparametricamplification(OPA)effectinhighnon-linearfiber(HNLF)isinvestigated.Intheproposedsystem,theOPAeffectoccurswhenthesignalandpumpwith30GHzfrequencyintervalaresetintothehighnon-linearfiber.BycontrollingthelengthofHNLF,OPAeffectsaturates,andthepumppowerisdeliveredinalargeextenttothesignalandidlerlight,soa60GHzOCSmm-waveisgenerated.Thesystemdoesnotneedhigh-speedexternalmodulator,high-frequencyvibrationsourceornarrow-bandfilter,whichgreatlyreducesthecostandimprovesthestabilityoftheradiooverfiber(ROF)system.Resultsshowthatthe10Gb/sdownstreamsignalcanbetransmittedwithnegligiblepowerpenalty.