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1、南京航空航天大學(xué)碩士學(xué)位論文移動(dòng)Adhoc網(wǎng)絡(luò)多樹視頻組播路由協(xié)議的研究姓名:胡杰申請學(xué)位級別:碩士專業(yè):計(jì)算機(jī)科學(xué)與技術(shù)指導(dǎo)教師:陳兵20081201南京航空航天大學(xué)碩士學(xué)位論文摘要隨著無線信道帶寬的增加和移動(dòng)設(shè)備計(jì)算能力的增強(qiáng),移動(dòng)Adhoc網(wǎng)絡(luò)中的視頻應(yīng)用將越來越多。視頻數(shù)據(jù)的速率高、軟實(shí)時(shí)、幀間依賴等特性和移動(dòng)Adhoc網(wǎng)絡(luò)的拓?fù)浣Y(jié)構(gòu)動(dòng)態(tài)變化、節(jié)點(diǎn)間多跳連接及無線信號(hào)的不穩(wěn)定等特征使得移動(dòng)Adhoc網(wǎng)絡(luò)中的視頻通信成為一個(gè)具有挑戰(zhàn)性的命題。Adhoc網(wǎng)絡(luò)平面式結(jié)構(gòu)的優(yōu)點(diǎn)之一是源節(jié)點(diǎn)與目的節(jié)點(diǎn)之間存在多條路徑,因而在源和目的節(jié)點(diǎn)之間采用多個(gè)路徑同時(shí)進(jìn)行數(shù)據(jù)傳輸可以保證視頻傳輸?shù)某掷m(xù)性和健
2、壯性,提高視頻接收質(zhì)量。本文研究了移動(dòng)Adhoc網(wǎng)絡(luò)中基于多組播樹的視頻組播技術(shù),即將組播技術(shù)與多路徑傳輸技術(shù)相結(jié)合,應(yīng)用MDC視頻編碼技術(shù)進(jìn)行視頻組播。多樹組播路由的基本思想是在組播源和組播接收者之間建立多棵組播樹,然后將視頻流分割成多個(gè)描述子碼流,每個(gè)子碼流在不同的樹上并發(fā)傳輸。文章首先介紹了移動(dòng)Adhoc網(wǎng)絡(luò)的各種組播路由協(xié)議,分析了現(xiàn)有組播路由協(xié)議不適用于移動(dòng)Adhoc網(wǎng)絡(luò)視頻傳輸?shù)脑颍岢隽艘苿?dòng)Adhoc網(wǎng)絡(luò)視頻組播協(xié)議應(yīng)滿足的要求;其次,研究比較了常用的幾種穩(wěn)定路徑選擇方法,采用基于鄰居變化率的穩(wěn)定路徑選擇方法,對MAODV組播路由協(xié)議進(jìn)行改進(jìn),使得組播樹的分支鏈路跳數(shù)少且比較穩(wěn)
3、定,仿真結(jié)果表明改進(jìn)后的協(xié)議——SP-MAODV協(xié)議提高了分組傳輸成功率,降低了路由開銷,減少了平均端到端傳輸時(shí)延;最后,對SP-MAODV協(xié)議進(jìn)行擴(kuò)展,提出一種新的多樹視頻組播路由協(xié)議MTVMR,該協(xié)議能在一次路由過程中建立兩棵節(jié)點(diǎn)盡量不相交的組播樹或使源節(jié)點(diǎn)能通過兩條相似度低的路徑與組播組相連,保證了視頻傳輸?shù)某掷m(xù)可達(dá)性,進(jìn)而提高了視頻傳輸質(zhì)量。關(guān)鍵詞:移動(dòng)Adhoc網(wǎng)絡(luò),組播,視頻,穩(wěn)定路徑,多樹,MAODV,多描述編碼i移動(dòng)Adhoc網(wǎng)絡(luò)多樹視頻組播路由協(xié)議的研究ABSTRACTWiththeincreasinglybroadenedwirelesschannelbandwidthan
4、denhancedcomputationcapabilityofthemobiledevices,videoapplicationswillbewidelyusedinthemobileAdhocnetworks.ThevideocommunicationbecomesthechallengeinthemobileAdhocnetworksbecauseofsuchfeaturesashighdatarate,softreal-timenatureandinter-framedependenceofthevideodata,aswellasthemobilityofnodes,time-var
5、yingnatureofthewirelesschannel.TheAdhocplanestructureprovidesmultiplepathsfromthesourcenodestothedestinationnodes,whichensuresthecontinuityandrobustnessofthedatatransmissionandimprovesthereceivequality.MDC-basedvideomulticasttechnologyinAdhocnetworkintegratestheadvantagesofsuchtechniquesasmultiplemu
6、lticasttreeandmulti-pathtransmission.Thebasicprincipleofmultipletreemulticastroutingistoestablishmultiplemulticasttreesbetweenthesenderandthereceiver,therebytodividethevideoflowintomultipleMDCsubflows.EachoftheMDCsubflowcanbetranmittedoverdifferenttrees.Firstly,variousmulticastroutingprotocolsapplic
7、abletomobileAdhocnetworksareintroduced,andthefeaturesandrequirementsoftheAdhocvideodatatransmissionareanalyzedinthispaper.Secondly,SP-MAODVisproposedastheimprovementofMAODVprotocolbasedonthestudyonthe