多径信道中UWB信号扩频码捕获T_(ma)性能分析.docx

多径信道中UWB信号扩频码捕获T_(ma)性能分析
Abstract
UWB(Ultra-wideband)technologyhasbeenwidelyusedincommunicationandradarsystemsduetoitshighbandwidth,lowenergyconsumptionandstronganti-interferenceability.However,inUWBcommunicationsystems,thepropagationcharacteristicsofthemultipathchannelmaycausetimingjitter,inter-symbolinterferenceandotherproblems,whichseriouslyaffectsthereliabilityofcommunication.Inthispaper,wefocusontheperformanceanalysisofT_(ma)incapturingspreadspectrumcodesundermultipathchannelconditions.
Introduction
UWBtechnologyisaradiocommunicationtechnologythatusesultra-widebandwidthsignalstotransmitandreceiveinformation.UWBtechnologyhasadvantagesoflowpowerconsumption,stronganti-interferenceabilityandhighdatarate.Inaddition,itcanprovidehighlyaccurateranginginformationfortargetdetection.However,duetothemultipathpropagationcharacteristicsofthecommunicationchannel,signaldistortion,timedelayandfrequencydispersionmayoccur,resultinginsignalinterferenceanddegradationofsystemperformance.
Thespreadspectrumtechnologyisaneffectivemethodtoimprovetheanti-interferenceabilityofUWBcommunicationsystems.Byusingspecificspreadingcodes,thenarrowbandsignalismodulatedtoawidebandsignal.Intheprocessofsignalreception,thereceivercancapturethespreadingcode,whichcaneffectivelysuppresstheinterferencefromothersignals.
T_(ma)isawidelyusedtechnologyinUWBspreadspectrumsystemstocapturespreadingcodes.Itmainlyusesamatchedfilteroracorrelationreceivertodetectthespreadingcode.T_(ma)performancedirectlyaffectsthesystem’santi-interferenceabilityanddetectionreliability.
MultipathSignalModel
Inamultipathchannel,thesignalreceivedbythereceiveriscomposedofmultiplesignalsreflectedbydifferentpaths,andisexpressedas:
r(t)=∑A_n(t-t_n)u(t-t_n)+n(t)
whereA_nistheamplitudeofthenthtransmissionpath,t_nisthetimedelayofthenthpath,u(t)isthetransmittedsignalandn(t)istheGaussiannoise.
Throughthewirelesschannel,thereceivedsignalsuffersfromattenuation,delayandphaseshift,whichcausethemultipathsignaltobedistorted.Themultipathsignalmayalsoo