资源描述：
《Ad_Hoc_Network英文简介.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、AdHocNetwork1、INTRODUCTIONThemobilecommunicationnetworkweoftenmentiongenerallyhasacenter.Itisrunningbasedonthepre-establishednetworkfacilities。Weknowthatthecommunicationrangeofthesatellitecommunicationsystemisthemostwidelyusedtoprovidecommunicationservicesforusersineverycornerofthew
2、orld.Inthissystem,satelliteplaysasimilarfunctionwiththebasestation.Butthecostofsatellitecommunicationssystemishigh,thepropagationdelay（传输延时）islongandthebandwidthislimited。Themobilecommunicationsystemrequiresthesupportofthewirednetworkcommunicationsinfrastructure(基础设施),suchasbasestat
3、ions,switches,satellites.Theestablishmentandoperationofthesefacilitiesrequirealotofmanpowerandmaterialresources,sothecostisrelativelyhigh,andthebuildingneedsalongtime.TheAdHocnetworkhostsnetworkbyitselfwithoutbasestations,therefore,thenetworkhasalowcost,whilethetimeisshort,itisonlya
4、fewsecondsorminutes.AdHocnetworkisaMulti-hop,nocenter,self-organizingwirelessnetwork，alsoknownasMulti-hopNetwork（多跳网）InfrastructurelessNetwork（无基础设施网）Self-organizingNetwork（自组织网）AdHocmodeisaP2Pconnection,itwillnotbeabletocommunicatewithothernetworks.Thewirelessterminal（无线终端）devicesu
5、sead-hocmode，suchasthePMP（PersonalMultimediaPlayer个人多媒体播放器）,PSP(PlayStationPortable掌上游戏机),DMA（DirectMemoryAccess存储器直接访问控制器).ForhomewirelessLocalAreaNetworksettingup,Ithinkweallknowthemostsimplethattwocomputerswithwirelessnetworkcardcompletewirelessinterconnection.Oneofthecomputersco
6、nnectedtotheInternetcansharethebandwidth.Asshown,astructureiscompletedtoformbasedonAdHocWLAN。NofixedinfrastructureintheentireAdHocnetwork,eachnodeismobileandcanbeinanywaytomaintaincontactwithothernodes.Inthisnetwork,owingtothelimitednatureoftheendwirelesscoveragerange，twousertermina
7、ls(终端)thatcannotdirectlycommunicatecanmakeuseofothernodesforpacketforwarding.Eachnodeisalsoarouter,theyareabletocompletediscoveryandtomaintainthefunctiontotheothernodesrouter.2、CHARACTERISTICSComparedwithordinarymobileandfixednetworks,ithasthefollowingcharacteristics:(1)Independence
8、(独立性)AdHocnetworkis
