資源描述:
《無線傳感器網(wǎng)絡(luò)高效mac協(xié)議的研究》由會員上傳分享,免費在線閱讀,更多相關(guān)內(nèi)容在學術(shù)論文-天天文庫。
1、摘要摘要無線傳感器網(wǎng)絡(luò)由于具有廣闊的應(yīng)用前景而在近幾年受到學術(shù)界和工業(yè)界的廣泛關(guān)注,是21世紀最重要的技術(shù)之一。介質(zhì)訪問控制(MAC)是無線傳感器網(wǎng)絡(luò)協(xié)議棧的重要組成部分,負責在傳感器節(jié)點間分配有限的無線通信資源,協(xié)調(diào)網(wǎng)絡(luò)中各節(jié)點的傳輸,構(gòu)成傳感器網(wǎng)絡(luò)系統(tǒng)的底層基礎(chǔ)結(jié)構(gòu)。目前無線傳感器網(wǎng)絡(luò)中的MAC協(xié)議主要分為發(fā)送端啟動的MAC協(xié)議和接收端啟動的MAC協(xié)議兩類。發(fā)送端啟動的MAC協(xié)議主要利用時鐘同步或前導傳輸建立發(fā)送端和接收端的連接,前者同步代價過高,后者網(wǎng)絡(luò)利用率較低。接收端啟動的MAC協(xié)議(RI-MAC)通過接收端主動與發(fā)送端建立連接,克服了發(fā)
2、送端啟動算法的弊端,但又產(chǎn)生了發(fā)送端盲等的問題,導致數(shù)據(jù)傳輸延遲和發(fā)送端能耗增大。本文在仔細研究已有MAC協(xié)議的基礎(chǔ)上,結(jié)合發(fā)送端啟動的MAC協(xié)議和接收端啟動的MAC協(xié)議的優(yōu)點,提出了一種可自適應(yīng)變換數(shù)據(jù)傳輸模式的MAC協(xié)議(IL-MAC)。該協(xié)議通過局部同步算法減少了發(fā)送端與接收端在建立連接時的盲等;根據(jù)節(jié)點的消息隊列長度和數(shù)據(jù)的緊急程度決定當前使用發(fā)送端啟動傳輸模式還是接收端啟動傳輸模式,有效地解決了以上兩類協(xié)議的問題。本文在網(wǎng)絡(luò)仿真平臺NS2上實現(xiàn)了IL-MAC協(xié)議,并在集中式拓撲、網(wǎng)狀拓撲和隨機拓撲三種網(wǎng)絡(luò)結(jié)構(gòu)下比較了IL-MAC和RI-M
3、AC的性能。仿真結(jié)果表明,IL-MAC在中低負載的條件下較有優(yōu)勢,而在高負載下明顯好于RI-MAC。關(guān)鍵詞:無線傳感器網(wǎng)絡(luò),MAC協(xié)議,自適應(yīng)傳輸模式變換I摘要ABSTRACTWirelesssensornetworks(WSN)havebroadapplicationsandsignificantvalue,andhavearousedtheindustryandacademicattention,itisoneofthemostimportanttechnologiesin21century.MediumAccessControl(MAC)pr
4、otocol,whichisapartofdatalinklayerinwirelesssensornetworksystem.Itsprimaryresponsibilityistoallocatethelimitedresourcesinwirelessnetworks,establishreliablecommunicationlinksbetweennodes,anditisusedtobuildthesensornetworksystemsinfrastructure.MACprotocolincurrentresearchisdivid
5、edintotwocategories,thesender-initiatedandthereceiver-initiated.Thesender-initiatedprotocolusingsynchronizationorthepreambletoestablishtheirconnection,hasproblemsarethatthecostofusingthesynchronizationistoohigh,andthelargenumberoflongpreamblesgreatlyreducesthenetworkutilizatio
6、n.Thereceiver-initiatedprotocol(RI-MAC)usethemessageperiodicallysendbythereceivertoestablishaconnectionwiththesender,itcansolvetheproblemsofthesender-initiatedprotocol,butintheRI-MACprotocol,thewaitingtimeofthesenderisgreatlyincreased,andthenitdelaysthetransferandincreasesthee
7、nergy-consumingofthesender.ThisthesisbasedonthecurrentresearchoftheMACprotocol,madefulluseofthebenefitsofthesender-initiatedandthereceiver-initiatedprotocol,proposeanewdutycycleMACprotocol,calledInitiator-convertibleandLocallysynchronizedMACProtocol(IL-MAC).Thisprotocolreduced
8、thewaitingtimeofthesenderandreceivertoestablishaconnection;By