信息與通信工程專業(yè)介紹英文版

BriefIntroductiontoInformationandCommunicationEngineering2011.5.30BriefIntroductiontoInformationandCommunicationEngineeringAmongalloftheessentialsforhumanexistence,theneedtointeractwithothersranksjustbelowourneedtosustainlife.Communicationisalmostasimportanttousasourrelianceonair,water,food,andshelter.Themethodsthatweusetoshareideasandinformationareconstantlychangingandevolving.Whereasthehumannetworkwasoncelimitedtoface-to-faceconversations,mediabreakthroughscontinuetoextendthereachofourcommunications.Fromtheprintingpresstomobilephone,eachnewdevelopmenthasimprovedandenhancedourcommunication.ThedevelopmentofCommunication（1）Inancienttimes，informationcouldbetransferredthroughlightorsound。光通信：中國--烽火臺(tái)、希臘—火炬的位置表示字母符號(hào)聲通信：中國—擊鼓鳴金（2）Beginningandturningpoint：1837-Morse-telegram；1876-Bell-telephone；1895-Marconi-radioThedevelopmentofCommunicationdevelopmentoftransmissionchannel

multicorecable—CoaxialCable—opticalfiber多芯電纜—同軸電纜—光纖developmentofCommunicationcomponents

vacuumtube—transistor—integratecircuit—largescaleintegratedcircuit真空管—晶體管—集成電路—大規(guī)模集成電路developmentoftransmissionmethod

telegram—voice—Muchcarriermodulation—pulse-codemodulation電報(bào)--聲音—多載波調(diào)幅—pcmdevelopmentofrangeofmessage

voice—text—graph，image聲音—文字—圖形、圖像

ThedevelopmentofCommunicationAswitheveryadvanceincommunicationtechnology,thecreationandinterconnectionofrobustdatanetworksishavingaprofoundeffect.Earlydatanetworkswerelimitedtoexchangingcharacter-basedinformationbetweenconnectedcomputersystems.Currentnetworkshaveevolvedtocarryvoice,videostreams,text,andgraphicsbetweenmanydifferenttypesofdevices.Previouslyseparateanddistinctcommunicationformshaveconvergedontoacommonplatform.Thisplatformprovidesaccesstoawiderangeofalternativeandnewcommunicationmethodsthatenablepeopletointeractdirectlywitheachotheralmostinstantaneously.ThefutureofCommunication（3）5w：whateverwhereverwhoeverwhomeverwhenever任何人在任何時(shí)間、任何地點(diǎn)接收來自任何人的任何信息ThefutureofCommunication

MobileCellularNetwork

MobileAdHocNetwork

FixedNetwork

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WLANWhatisCommunication？Asweallknow，networkscansupportthewaywelearn，thewayweworkandthewayweplay.Livinginanetwork-centricworld,communicationisanessentialpartofourlives.WhatisCommunication？WhatisCommunication？Communicationinourdailylivestakesmanyformsandoccursinmanyenvironments.Eachsituationhasitscorrespondingexpectedbehaviorsandstyles.EstablishingtheRulesBeforebeginningtocommunicatewitheachother,weestablishrulesoragreementstogoverntheconversation.Theserules,orprotocols,mustbefollowedinorderforthemessagetobesuccessfullydeliveredandunderstood.

Amongtheprotocolsthatgovernsuccessfulhumancommunicationare:AnidentifiedsenderandreceiverAgreeduponmethodofcommunicating(face-to-face,telephone,letter,photograph)CommonlanguageandgrammarSpeedandtimingofdeliveryConfirmationoracknowledgementrequirementsEnsureQualityofCommunicationsCommunicationbetweenindividualsisdeterminedtobesuccessfulwhenthemeaningofthemessageunderstoodbytherecipientmatchesthemeaningintendedbythesender.Theexternalfactorsaffectingcommunicationarerelatedtothecomplexityofthenetworkandthenumberofdevicesamessagemustpassthroughonitsroutetoitsfinaldestination.EnsureQualityofCommunicationsInternalfactorsthatinterferewithnetworkcommunicationarerelatedtothenatureofthemessageitself.Boththeinternalandexternalfactorsthataffectthereceiptofamessagemustbeanticipatedandcontrolledfornetworkcommunicationstobesuccessful.Newinnovationsinnetworkhardwareandsoftwarearebeingimplementedtoensurethequalityandreliabilityofnetworkcommunications.CommunicationoverNetworksBeingabletoreliablycommunicatetoanyone,anywhere,isbecomingincreasinglyimportanttoourpersonalandbusinesslives.Inordertosupporttheimmediatedeliveryofthemillionsofmessagesbeingexchangedbetweenpeopleallovertheworld,werelyonawebofinterconnectednetworks.Thesedataorinformationnetworksvaryinsizeandcapabilities,butallnetworkshavefourbasicelementsincommon:Rulesoragreementstogovernhowthemessagesaresent,directed,receivedandinterpretedThemessagesorunitsofinformationthattravelfromonedevicetoanotherAmeansofinterconnectingthesedevices-amediumthatcantransportthemessagesfromonedevicetoanotherDevicesonthenetworkthatexchangemessageswitheachotherTheElementsofaNetworkThediagramshowselementsofatypicalnetwork,includingdevices,media,andservices,tiedtogetherbyrules,thatworktogethertosendmessages.TheElementsofaNetwork：devicesTheElementsofaNetwork：devicesSwitch-themostcommondeviceforinterconnectinglocalareanetworksFirewall-providessecuritytonetworksRouter-helpsdirectmessagesastheytravelacrossanetworkWirelessRouter-aspecifictypeofrouteroftenfoundinhomenetworksTheElementsofaNetwork：mediumTheElementsofaNetwork：mediumForanetworktofunction,thedevicesmustbeinterconnected.Networkconnectionscanbewiredorwireless.Inwiredconnections,themediumiseithercopper,whichcarrieselectricalsignals,oropticalfiber,whichcarrieslightsignals.Inwirelessconnections,themediumistheEarth'satmosphere,orspace,andthesignalsaremicrowaves.TheElementsofaNetwork：：rulesHumanbeingsoftenseektosendandreceiveavarietyofmessagesusingcomputerapplications;theseapplicationsrequireservicestobeprovidedbythenetwork.SomeoftheseservicesincludetheWorldWideWeb,e-mail,instantmessaging,andIPTelephony.Devicesinterconnectedbymediumtoprovideservicesmustbegovernedbyrules,orprotocols.Inthechart,somecommonservicesandaprotocolmostdirectlyassociatedwiththatservicearelisted.TheElementsofaNetwork：rulesTheElementsofaNetwork：messagesInthefirststepofitsjourneyfromthecomputertoitsdestination,ourinstantmessagegetsconvertedintoaformatthatcanbetransmittedonthenetwork.Alltypesofmessagesmustbeconvertedtobits,binarycodeddigitalsignals,beforebeingsenttotheirdestinations.Thisistruenomatterwhattheoriginalmessageformatwas:text,video,voice,orcomputerdata.Onceourinstantmessageisconvertedtobits,itisreadytobesentontothenetworkfordelivery.TheElementsofaNetwork：messageschannelMultipleservices-multiplenetworksTraditionaltelephone,radio,television,andcomputerdatanetworkseachhavetheirownindividualversionsofthefourbasicnetworkelements.Inthepast,everyoneoftheseservicesrequiredadifferenttechnologytocarryitsparticularcommunicationsignal.Additionally,eachservicehaditsownsetofrulesandstandardstoensuresuccessfulcommunicationofitssignalacrossaspecificmedium.Multipleservices-multiplenetworksConvergedNetworksTechnologyadvancesareenablingustoconsolidatethesedisparatenetworksontooneplatform-aplatformdefinedasaconvergednetwork.Theflowofvoice,video,anddatatravelingoverthesamenetworkeliminatestheneedtocreateandmaintainseparatenetworks.Onaconvergednetworktherearestillmanypointsofcontactandmanyspecializeddevices-forexample,personalcomputers,phones,TVs-butonlyonecommonnetworkinfrastructure.ConvergedNetworksWhatisrequiredforus？Convergednetworks,whichcarryallcommunicationstypes(data,voice,andvideo)ononeinfrastructure,provideanopportunitytoreducecostsandofferusersfeature-richservicesandcontent.However,thedesignandmanagementofconvergednetworksrequiresextensivenetworkingknowledgeandskillsifallservicesaretobedeliveredasexpectedtousers.Differenttypesofcommunicationsflowingacrossourdatanetworksneedtobeprioritizedsothatthetime-sensitiveandimpo