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1、TheDevelopmentofMobilePhoneAmobilephone(alsocalledmobile,cellulartelephone,cellphone,handphoneorhandy)isanelectronicdeviceusedfortwo-wayradiotelecommunicationoveracellularnetworkofbasestationsknownascellsites.Mobilephonesdifferfromcordlesstelephones,whichonlyoffertel
2、ephoneservicewithinlimitedrangethroughasinglebasestationattachedtoafixedlandline,forexamplewithinahomeoranoffice.Amobilephoneallowsitsusertomakeandreceivetelephonecallstoandfromthepublictelephonenetwork,whichincludesothermobilesandfixed-linephonesacrosstheworld.Itdoe
3、sthisbyconnectingtoacellularnetworkownedbyamobilenetworkoperator.Akeyfeatureofthecellularnetworkisthatitenablesseamlesstelephonecallsevenwhentheuserismovingaroundwideareasviaaprocessknownashandofforhandover.Inadditiontobeingatelephone,modernmobilephonesalsosupportman
4、yadditionalservices,andaccessories,suchasSMS(ortext)messages,e-mail,Internetaccess,gaming,Bluetoothandinfraredshortrangewirelesscommunication,camera,MMSmessaging,MP3player,radioandGPS.Low-endmobilephonesareoftenreferredtoasfeaturephones,whereashigh-endmobilephonestha
5、toffermoreadvancedcomputingabilityarereferredtoassmartphones.Dr.MartinCooperofMotorolademonstratedthefirsthandheldmobilephonein1973,usingahandsetweighing2kg(4.4lb).Motorolareleasedthefirstcommerciallyavailablemobilephone,theDynaTAC8000x,in1983.Intheyear1990,12.4milli
6、onpeopleworldwidehadcellularsubscriptions.Bytheendof2009,lessthan20yearslater,thenumberofmobilecellularsubscriptionsworldwidereachedapproximately4.6billion,370timesthe1990number,penetratingthedevelopingeconomiesandreachingthebottomoftheeconomicpyramid.Historyofmobile
7、phonesRadiophoneshavealongandvariedhistorygoingbacktoReginaldFessenden'sinventionandshore-to-shipdemonstrationofradiotelephony,throughtheSecondWorldWarwithmilitaryuseofradiotelephonylinksandcivilservicesinthe1950s.ThefirstmobiletelephonecallmadefromacaroccurredinSt.L
8、ouis,Missouri,USAonJune17,1946,butthesystemwasimpracticalfromwhatisconsideredaportablehandsettoday.Theequipmentweighed80lbs,andtheA
