Joint wireless communication and radar sensing system1Word文档格式.docx

Joint wireless communication and radar sensing system1Word文档格式.docx

《Joint wireless communication and radar sensing system1Word文档格式.docx》由会员分享，可在线阅读，更多相关《Joint wireless communication and radar sensing system1Word文档格式.docx（12页珍藏版）》请在冰豆网上搜索。

Jointwirelesscommunicationandradarsensingsystem1@#@Jointwirelesscommunicationandradarsensingsystems–stateoftheartandfutureprospects@#@LiangHan,KeWu@#@Poly-GramesResearchCenter,CenterforRadiofrequencyElectronicsResearchofQuebec（CREER）,DepartmentofElectricalEngineering,EcolePolytechnique,UniversityofMontreal,Montreal,Quebec,CanadaH3T1J4E-mail:

@#@liang.han@polymtl.ca@#@Abstract:

@#@Thehistoricaldevelopmentandcurrentstate-of-the-artofvariousjointwirelesscommunicationandradarsensingsystemsarereviewedanddiscussedinthisstudy.Differentkindsofsystemsarecategorisedaccordingtotheirmodulationwaveformsandduplexschemes.Prosandconsofeachcategoryarehighlighted.Toshowcasethecurrentresearchadvances,severaldemonstrationsystemsareintroducedwithemphasisonproposedresearchcontributionsinthisemergingarea,andtheirperformancesarecomparedwithrespecttobothcommunicationandradarmodes.Also,anumberofchallengesareidentifiedforthenearfuturesystemdevelopmentsandapplications.@#@1Introduction@#@Theinventionofradiousheredthehistoryofmankindintoanewera.Amongvarioustypesofradioapplicationsknowntodate,themostubiquitousandprominenttwoofthemarewirelesscommunicationandradarsensing.Sincetheverybeginning,thesetwosortsofsystemshavebeendesignedanddevelopedinaquitedifferentmanner,eventhoughbothmakeuseofradiofrequencytransceiverfunctionalblocks.Ofcourse,theyhavegenerallybeenindependentlyandseparatelystudiedanddevelopedfromeachotherinmostscenariosexceptforsomeprimitiveapplicationexamplesofsystemfusionbetweenthemsuchastheso-calledsecondarysurveillanceradarsystemortheidentificationfriendorfoe（IFF）system[1].Althoughinformationexchangeisenabledinsuchkindofradarsystems,theresponderisingeneralnotabletotransmitdatatotheinterrogatorautonomously.Thereforedatafusionschemesbasedonthiskindofsystemoperation,thatis,radar-embeddedcommunications[2]andUWBRFID[3],willnotbefurtherdiscussedinthispaperbecausesuchsystemsdonotpresenta‘truly’blendedtransceiverarchitecturethatsimultaneouslypossessescommunicationandradarfunctions.@#@Ifsuccessfullyimplemented,thesystemfusionofwirelesscommunicationandradarsensingwoulddefinitelybringupmanybenefitsincludingarchitectureunificationandsimplification,functionalreconfigurationandfusionandespeciallyefficiencyenhancementandcostreduction.Naturally,thefusionoftwosystemsthroughonesingletransceiverallowsthereal-timeinterplayand‘dialogue’betweentwodifferentfunctions.AnearlyexampleofintegratedradarandcommunicationsubsystemcanbetracedbacktotheNASASpaceShuttleOrbiter[4].Recently,therehasbeenamultitudeofemergingneedsforintegratingwirelesscommunicationandradarsensingsystems.Theintelligenttransportationsystems[5],forexample,requireintelligentvehiclestohavethecapabilityofautonomouslysensingthedrivingenvironmentandcooperativelyexchanginginformationdatasuchasvelocityandbrakingbetweenvehiclesandalsoroad,trafficandweatherconditionsaswellasentertainmentcontentamongvehiclesandbeacons.Anotherexampleisthewirelesssensornetworks（WSN）[6]forpositioningandmonitoringpurposes,inwhicheachnodedetectstargetsandsharesitsinformationwithothernodesthroughwirelesscommunicationlinks,whichshouldbedesirablypartoftheWSNsystem.Furthermore,itshouldbementionedthatmultifunctionalin-situsystemswithactiveprotectionradar,widebandcommunicationsandcombatidentificationarealsohighlydemandedformodernmilitaryapplications[7].@#@Theunprecedentedsystemfusionhasgenerallypresentedmanystringentdesignrequirementssuchaslow-cost,simpleimplementation,flexiblefunctionalreconfigurationandhigh-powerefficiencyaswellasfastresponse.Thisisbecausethesystemfusionorintegrationshouldbemuchmoreadvantageousthanitspuremechanicallyassembledcounterpartoftwoseparatesystemarchitectures.Inthepasthalf-decade,anumberofsystemconceptswithrespecttowaveformdesignandtransceiverdevelopmenthavebeenproposedtointegratebothwirelesscommunicationandradarsensingfunctionswithinasingletransceiversystem.Thispaperbrieflyreviewsandsummarisesthestate-of-the-artsystems,describesanddiscussessomedemonstrationsystems,andpointsoutseveralchallengesforfuturesystemdevelopments.@#@2Waveformdesign@#@Differentunderlyingoperationprinciplesofwirelesscommunicationandradarsensingsystemssuggestdifferentrequirementswithregardtocertainsystemandtransceiverdesignconsiderations,suchasduplexmode,modulationschemeandbandwidthaswellassignalprocessingalgorithms.Forinstance,frequencydivisionduplexmodecommonlyusedinwirelesscommunicationisnotsuitableforradarapplicationssincethespectraoftransmittedandreceivedradarsignalsarealmostco-locatedinthesamefrequencychannel.Inmostcases,thedesignrequirementsforcommunicationandradarfunctionsmaybeinconflict,whichposeagreatchallengeinthedevelopmentofsuchsystemarchitecturefusions.Withrapidprogressofdigitalcircuits,therehasbeenatrendtosimplifythedesignofradio-frequency（RF）front-endcircuitsbyimplementingmostofthesystemfunctionsbaseduponsoftware-reconfigurablesignalprocessingalgorithms.Thesesoftware-definedradioplatformsprovideuswithagoodopportunitytoachievejointcommunicationandradaroperationswithinthesameRFfront-endcircuit.@#@Table1summarisestheprosandconsoftypicalcommunication–radarfusionschemesthathaverecentlybeenproposedandstudiedin[8–24].Thejointwaveformschemecanbefurthercategorisedintosingle-carrierandmulti-carriersystems.Inthesingle-carriersystems,thefrequency-domainschemeisfoundmuchlesspopularthanitscode-domain（spreadspectrum）counterpartsbecauseofthemutualorcross-channelinterferencecausedbythespectrumoverlapping[8].Thespreadspectrumtechniquewasfirstlyimplementedinaboomerangtransmissionsystemforvehicularcommunicationandrangingapplications[9].Essentially,theproposedsystemissimilartoanIFFsystemexceptthatitadoptsthedirect-sequencespreadspectrum（DSSS）techniquetoimprovethesystemperformance.Followingthatdevelopment,thespreadspectrumtechniquehaswidelybeenexploitedforfusingcommunicationandradarfunctions,suchasDSSS[9–13],THSS[14]andCSS[15].Thecode-domainschemesallowforsecurecommunicationandhigh-resolutionrangingattheexpenseofutilisingexcessivespectrumresourcesfordatacommunication.Moreover,differentuserscansharethesamefrequencybandsimultaneouslybyusingdifferentspreadingcodes,whichisverybeneficialformultiuserapplicationscenarios.RegardingtheradarrangingandDopplerestimationbasedonthespreadspectrumtechnique,therearetwomaindrawbacks.Oneisthatthepeak-to-sideloberatioislimitedbytheimperfectauto-correlationcharacteristicsofthepseudorandomcodes,anditisalsoimpactedbythespreadingfactorandtheDopplershift.TheotheristhatforDopplerprocessing,thespreadspectrumtechniquerequiresahugeamountofcomputations.Ingeneral,theconcernofusingaspreadspectrumtechniqueisrelatedtoitshighcomplexityandcostandlowefficiencyintermsofsystemimplementation.@#@Multi-carrier,especiallytheorthogonalfrequency-divisionmultiplexing（OFDM）technique,whichhaswidelybeenusedinwirelesscommunications,wasalsointroducedinthedesignofradarwaveform[25].TheuseofOFDMradarwaveformswasdemonstratedinmultiple-inputandmultipleoutput（MIMO）radarsystems[16]andradarnetworks[26,27]aswellassyntheticapertureradar（SAR）systems[17,28–30].OneattractivefeatureoftheOFDMradarsignalsisthatthereisnorange–DopplercouplingissueandthereforeindependentrangeandDopplerprocessingbecomespossible[31,32].Inthepastfewyears,differentsignalprocessingtechniqueshavebeenproposedandimplemented.Inthebeginning,matchedfilterswereusedtoperformrangeandDopplerestimationin[18,33–37].However,correlation-basedprocessingmethodstillsuffersfromsuchproblemsaslowdynamicrange（orpeak-to-sideloberatio）andambiguities.Inordertoincreasethedynamicrangeandpreservethetransmittedcommunicationdata,anovel‘modulationsymboldomain’OFDMprocessingalgorithmwasproposed[38–41]andvalidatedthroughexperimentalsystemprototypes[19,42].Althoughpreservingtheresolutionandtheprocessinggainofthecorrelation-basedprocessingmethod,thisadvancedjointrangeandDopplerestimationalgorithmfortheOFDM-basedjointwaveformhasmuchhigherdynamicrangethanthesingle-carrierspreadspectrumapproachbymanyordersofmagnitude,especiallyforhighSNRlevels.Moreover,theDopplerfrequency（ortargetrelativevelocity）canbeeasilyestimatedindependentlyfromthetargetrange.Acomprehensivereviewoftheproposedsignalprocessingtechniqueandrelatedsystemdemonstrationcanbefoundin[43].Thistechniquehasbeenrecentlyextendedtotackleamultipathandmultiuserscenarioin[44].AlthoughtheOFDMtechniqueshavepresentedanumberofadvantageslistedinTable1,thehighimplementationcostofOFDMsystemsbecauseofthecomplexsignalprocessingandhighpeak-to-averagepowerratioofOFDMsignalsstillimpedetheirwidespreadapplications.@#@Almostinparallelwiththejointwaveformscheme,thetime-domainduplexschemehasalsostimulatedresearchinterestbecauseofitshighspectralefficiencyandeasysystemimplementationaswellaslowcost[20–24].Inthetime-domainplatforms,comm