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英文文献TheApplicationofonepointMultipleAccessSpreadSpectrumCommunicationSystemLiuJiangang,NanyangCity,HenanProvinceElectricPowerIndustryBureau【ABSTRACT】SpreadSpectrumDigitalMicrowavecommunicationasacommunication,becausetheirexcellentperformancehavebeenwidelyused.ThearticleinNanyangCityPowerIndustryBureauonepointMultipleAccessSpreadSpectrumCommunicationSystemasanexample.briefedthespreadspectrumcommunications,thebasicconceptandcharacteristicsofthepowersystemcommunicationapplications.KEYWORDS：onepointmultipleaccess;Spread-spectrumcommunication;AttenuationNanyangCityintheoutskirtsofCentralcloth35to11kvsubstationfarmterminals,theiroperationmanagementrightsbelongtotheCouncilEast,RuralPowerCompanywest(theeasternsuburbofagriculturalmanagementcompanies--four,thewesternsuburbsofRuralPowerCompanyManagement7),SchedulingofthevariousstationsofthemeansofcommunicationtotheoriginalM-150radioandtelephoneposts.2002Withthetransformationofruralnetwork,theremotestationequipmentintooperationandcommunicationchannelstoputahigherdemand.AsPUCDispatchCommunicationBuildingtotheeastandwestoffarmers--thedifferencebetweenacompanylinkedtofiber,Therefore,if11substationsandtheestablishmentofatransferLinkBuildinglinksPointmaybethedataandvoiceweresenttotworuralpowercompaniesdispatchroom,RuralNetworkschedulingfortheimplementationofautomationtocreatethenecessaryconditions.Giventhestatusandpowergridsubstationlevel,nature,takingintoaccountthecarrierandoptical-fibercommunicationstoconductmultipleforwarding,increasingtheinstabilityfactor,consideringthecostandconditionsoftheurbanconstruction,Finallydecidedtoadoptwirelessspread-spectrumtechnologytoestablishthat11farmterminalsubstationcommunicationsystem.Thispaperdescribesthespreadspectrumtechnologyandthecurrentsystemofthebuilding.1.Thebasicconceptofspread-spectrumcommunication.SpreadSpectrumCommunication'sbasiccharacteristics,isusedtotransmitinformationtothesignalbandwidth(W)isfargreaterthanthepracticalinformationrequiredminimum(effective)bandwidth(△F),astheratioofprocessinggainGP.GP=W/△FAsweallknow,theordinaryAM,FM,orpulsecodemodulationcommunications,GPvaluesintheareamorethan10times,collectively,thenarrow-bandcommunication,andspread-spectrumcommunicationsGPvaluesashighashundredsoreventhousandsoftimes,canbecalledbroadbandcommunications.Duetothespread-spectrumsignal,itisverylowpowertransmitters,transmissionspacemostlydrownedinthenoise,itisdifficulttointerceptedbytheotherreceiver,onlyspreadingcodeswiththesame(orrandomPNcode)receiver,Gaincanbedealtwith,anddispreadingresumetheoriginalsignal.2.Thetechnologysuperiorityofspread-spectrumcommunication.Stronganti-interference,biterrorrateislow.Asnotedabove,thespreadspectrumcommunicationsystemduetotheexpansionofthetransmittersignalspectrum,thereceiverdispreadingreductionsignalproducedspreadinggain,therebygreatlyenhancingitsinterferencetolerance.Underthespreadinggain,orevennegativeinthesignal-to-noiseratioconditions,canalsosignalfromthenoisedrownedoutExtraction,inthecurrentbusinesscommunicationssystems,spreadspectrumcommunicationisonlyabletoworkinanegativesignal-to-noiseratioundertheconditionsofcommunication.Anti-multi-pathinterferencecapability,increasethereliabilityofthesystem.Spread-spectrumsystemsasusedinthePNhasagoodcorrelation,correlationisveryweak.differentpathstothetransmissionsignalcaneasilybeseparatedandmayintimeandre-alignmentphase,formationofseveralsuperimposedsignalpower,therebyimprovingthesystem'sperformancetoreceiveincreasedreliabilityofthesystem.Easytousethesamefrequency,improvingthewirelessspectrumutilization.Wirelessspectrumisveryvaluable,althoughlong-wavemicrowavehavetobeexploited,andstillcannotmeettheneedsofthecommunity.Tothisend,countriesaroundtheworldaredesignedspectrummanagement,userscanonlyusethefrequencyapplications,relyonthechanneltopreventthedivisionbetweenthechannelinterference.Duetotheuseofspread-spectrumcommunicationrelatedreceivethishigh-tech,lowsignaloutputpower(aW,asageneral-100mW),andwillworkinthechannelnoiseandthermalnoiseinthebackground,easytoduplicateinthesameareausingthesamefrequency,cannowallsharethesamenarrow-bandfrequencycommunicationsresources.Spreadspectrumcommunicationisdigitalcommunications,particularlyfordigitalvoiceanddatatransmissionwhile,spreadspectrumcommunicationwiththeirownencryption,onlyinthesamePNcodecommunicationbetweenusers,isgoodforhidingandconfidentialinnature,facilitatingcommunicationsbusiness.Easytousespread-spectrumCDMAcommunications,voicecompressionandmanyothernewtechnologies,moreapplicabletocomputernetworksanddigitizationofvoice,imageinformationtransmission.Communicationisthemostdigitalcircuits,equipment,highlyintegrated,easyinstallation,easymaintenance,butalsoverycompactandreliable.Theaveragefailureratenotimewasverylong.Wehavedecidedtoadoptthespread-spectrumcommunicationtechnologyconstructionof11farmterminalsubstationcommunicationssystem,Duetothespread-spectrumcommunicationbytheline-of-sighttransmissiondistancerestrictions,hasbecomeunstoppablesystemdesignpremise.IfthePUCschedulingBuildingand11substation