专业英语作业移动通信的发展史.docx
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专业英语作业移动通信的发展史.docx
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专业英语作业移动通信的发展史
专业英语作业-移动通信的发展史
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2016/6/21Tuesday
Thisarticlemainlyintroducesthehistoryofthedevelopmentofmobilecommunication.Combinedwiththefirstgeneration,secondgeneration,thethirdgeneration,thecoretechnologyofthefourthgenerationmobilecommunicationofeachgenerationcommunicationtechnologyadvantagesanddisadvantageswereintroduced,toeveryoneofeverygenerationmobilecommunicationiswhat,andtheirproductionanddevelopmenthaveasystemofunderstanding.
IntroductionofTheDevelopmentofMobileCommunication
Abstract:
Thisarticlemainlyintroducesthehistoryofthedevelopmentofmobilecommunication.Combinedwiththefirstgeneration,secondgeneration,thethirdgeneration,thecoretechnologyofthefourthgenerationmobilecommunicationofeachgenerationcommunicationtechnologyadvantagesanddisadvantageswereintroduced,toeveryoneofeverygenerationmobilecommunicationiswhat,andtheirproductionanddevelopmenthaveasystemofunderstanding.
Keywords:
mobile;communication;development
Introduction:
Mobilecommunicationreferstothecommunicationandexchangeofinformationbetweenthetwopartiesatleastonesideinthemobileenvironment,whichincludesthecommunicationbetweenthetwosidesofthecommunicationandthemobileobjectandthefixedpointinthemobileenvironment.Mobilecommunicationispartofanintegralpartofmoderncommunicationsystems,mobilecommunicationappearedtobreakthefixedrelationshipbetweencommunicationandplace.ItuseswirelesstechnologytosolvetheInternetcan'tsolvethemobility,sothatpeopleinthemobileinformationacquisitionandinteractive.Itsdevelopmentandpopularizationhaschangedthesociety,butalsochangedthewayoflifeofmankind,sothatpeopleunderstandtheeraofhigh-speedinformationoftheatmosphere.
Modernmobilecommunicationtechnologyoriginatedinthetwentiesofthe20thcentury,themidseventiesofthe20thcentury,itusheredintherapiddevelopmentofmobilecommunication,untilnowtheOFDMTechnologyinthefourthgenerationcommunicationapplicationandthedevelopmentofmobilecommunicationwitheachpassingday.
1.Thefirstgenerationofmobilecommunicationsystem(1g)
Firstgeneration(1g)isthegenerationofmovingcommunicationsystem,simulationofcellularmobilecommunicationsystems,theuseofanalogmodulationandmultipleaccesstechniqueisfrequencydivisionmultipleaccess(FDMA),themodulationisafrequencymodulation(FM),themainbearingvoiceservice.ThefirstgenerationmobilecommunicationtotheUnitedStatesofAmerica'sAMPSsystemandtheEuropeanTACSastherepresentative,ourcountryinthelate80's,introducedtheTACStechnology,andbuiltthefirstpublicmobilecommunicationnetworkinChina.
Duetodifferentcountriesadoptdifferentstandard,differentbandandchannelbandwidth,roaminguserisnotconvenient,makingthefirstgenerationofmobilecommunicationsystemjustaregionalmobilecommunicationsystem,inaddition,inuseprocess,analogcellularmobilecommunicationsystemexposedalotofproblems,suchasspectralefficiencylow,singletypeofbusinessandthecallinterruptrateishigh,communicationequipment,heavy,butthethemainproblemisthebandresourceandcommunicationcapacityandgrowingofmobilecommunicationusersoflargecapacity,multiserviceandhighqualityserviceofmobilecommunicationdemandcontradictionhavebecomeincreasinglyprominent.Demandtopromotethedevelopment.Atthistimetheemergenceofdigitalsignal,allowspeopletosee,thetransmissionofdigitalsignalscanbeatransmissionoftheanalogsignalanddigitalsignalthanthatofanalogsignalshavemoresuperiorperformance,strongconfidentiality,errorpronetorestoreanddigitalcommunicationthananalogcommunicationhavemorekindsofbusiness.Makepeoplelookfromanalogcommunicationtodigitalcommunication.
2.Thesecondgenerationofmobilecommunicationsystems(2g)
2G(SecondGeneration)Thesecondgenerationmobilecommunicationsystem,ithastwokindsofmultipleaccessmethods,onekindistimedivisionmultipleaccess(TDMA),multipleaccess(CDMA)isakindofcodepoints.RepresentativesofTDMAIStheEuropeanGSMsystem,therepresentativeoftheCDMAIStheIS-95systemoftheUnitedStates.GSMstandardsystemmoreperfect,thetechnologyisrelativelymature.Comparedwiththefirstgenerationofmobilecommunicationsystem,thesecondgenerationmobilecommunicationsystem,thefrequencyandtimeusedincombinationtoaddressing,improvetheutilizationrateofthespectrum,canprovidegreatercapacity;Anti-interferenceandantifadingabilityenhancement,canguaranteegoodvoicequality.Theconfidentialityofthesystemisbetter;Butthelowspeedofdatatransmission,databusinessdevelo
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- 专业 英语 作业 移动 通信 发展史