發(fā)布時(shí)間：2018-08-11 12:16

【摘要】：早在18世紀(jì),亞當(dāng)斯密就在《國(guó)富論》中指出:“一切改良中,以交通運(yùn)輸?shù)母牧甲顬橛行��！彪S著汽車(chē)在人們?nèi)粘Ｉ钪兴缪莸慕巧絹?lái)越重要,以“行人、車(chē)輛、道路資源最優(yōu)化利用”為目標(biāo)的智能交通系統(tǒng)成為國(guó)家經(jīng)濟(jì)發(fā)展的重要載體,而車(chē)聯(lián)網(wǎng)是保障智能交通系統(tǒng)有效運(yùn)行的神經(jīng)中樞。為了保證車(chē)聯(lián)網(wǎng)信息交互的可靠性、有效性及穩(wěn)定性,從而提升公路交通系統(tǒng)的事故避免率、道路暢通性及運(yùn)行智能化的水平,研究適用于車(chē)聯(lián)網(wǎng)的內(nèi)容傳輸機(jī)制具有重要意義。本論文針對(duì)車(chē)聯(lián)網(wǎng)通信鏈路動(dòng)態(tài)特性和多種不同類(lèi)型的車(chē)載應(yīng)用需求,采用模型構(gòu)建、機(jī)制設(shè)計(jì)、理論分析及系統(tǒng)仿真等手段,圍繞移動(dòng)性感知的車(chē)聯(lián)網(wǎng)內(nèi)容傳輸機(jī)制展開(kāi)研究。論文的創(chuàng)新性工作主要包括如下幾個(gè)方面:1)針對(duì)車(chē)輛移動(dòng)相關(guān)性和無(wú)線信道衰落相關(guān)性,提出了車(chē)聯(lián)網(wǎng)場(chǎng)景下鏈路持續(xù)時(shí)間的理論模型,解決了拓?fù)渥兓l繁網(wǎng)絡(luò)條件下無(wú)線通信鏈路連通性能的有效數(shù)學(xué)刻畫(huà)問(wèn)題�；诙S離散馬爾科夫鏈模型,將時(shí)空相關(guān)性分別建模為車(chē)輛間或車(chē)對(duì)地相對(duì)距離狀態(tài)的轉(zhuǎn)移,得到了通信鏈路持續(xù)時(shí)間的概率質(zhì)量函數(shù)。理論分析和仿真驗(yàn)證表明所提出的模型能夠在低復(fù)雜度條件下,有效地描述車(chē)輛移動(dòng)相關(guān)性和陰影衰落相關(guān)性對(duì)鏈路持續(xù)時(shí)間的影響;2)針對(duì)無(wú)中心車(chē)聯(lián)網(wǎng)的多跳內(nèi)容傳輸,提出了基于退避計(jì)數(shù)器的無(wú)信標(biāo)傳輸協(xié)議,解決了動(dòng)態(tài)拓?fù)錀l件下傳輸機(jī)制設(shè)計(jì)需要綜合考慮傳輸有效性和鏈路穩(wěn)定性的難題。提出了聯(lián)合考量單跳傳輸距離和鏈路持續(xù)時(shí)間的新型基于退避計(jì)數(shù)器的無(wú)信標(biāo)傳輸策略,并針對(duì)無(wú)信標(biāo)協(xié)議鏈路構(gòu)建時(shí)延,建立了半馬爾科夫過(guò)程模型,推導(dǎo)了道路車(chē)流密度和車(chē)輛移動(dòng)速度等因素對(duì)傳輸路徑構(gòu)建時(shí)延的影響。仿真結(jié)果表明,協(xié)議能夠?qū)崿F(xiàn)無(wú)中心車(chē)聯(lián)網(wǎng)環(huán)境中的高穩(wěn)定性多跳傳輸,理論模型能夠有效描述無(wú)信標(biāo)協(xié)議傳輸鏈路構(gòu)建時(shí)延性能;3)針對(duì)有中心車(chē)聯(lián)網(wǎng)的多跳內(nèi)容傳輸,提出了稀疏路邊基礎(chǔ)設(shè)施布設(shè)條件下的車(chē)對(duì)地內(nèi)容上傳算法,解決了進(jìn)行多跳傳輸路徑構(gòu)建需求聯(lián)合考慮網(wǎng)絡(luò)動(dòng)態(tài)拓?fù)浜偷缆奋?chē)流狀態(tài)的難題。利用車(chē)輛中繼提升了基礎(chǔ)設(shè)施的覆蓋性能,構(gòu)建了車(chē)輛向基礎(chǔ)設(shè)施傳輸?shù)闹欣^車(chē)輛和調(diào)制編碼方式選擇問(wèn)題,分別針對(duì)單跳和多跳鏈路提出了目標(biāo)內(nèi)容完整傳輸?shù)膯l(fā)式近似算法。理論推導(dǎo)和仿真結(jié)果表明,算法能夠提升傳輸鏈路穩(wěn)定性,在降低方案實(shí)現(xiàn)復(fù)雜度的同時(shí),縮短了整體內(nèi)容傳輸時(shí)延;4)針對(duì)車(chē)聯(lián)網(wǎng)基于多播的內(nèi)容傳輸,提出了多樣車(chē)載用戶需求和動(dòng)態(tài)網(wǎng)絡(luò)拓?fù)錀l件下的資源調(diào)度問(wèn)題,解決了分層編碼視頻在道路區(qū)域同時(shí)滿足傳輸全覆蓋和高吞吐量?jī)煞矫嬉蟮膯?wèn)題。針對(duì)分層編碼視頻信息,考慮了道路車(chē)流密度以及車(chē)載用戶設(shè)備所能夠播放視頻的解析度不同,將基礎(chǔ)設(shè)施向視頻信息請(qǐng)求車(chē)輛多播調(diào)度問(wèn)題分解為“請(qǐng)求用戶全覆蓋的基本層視頻調(diào)度子問(wèn)題”和“有限多播資源條件下高吞吐量性能的擴(kuò)展層視頻調(diào)度子問(wèn)題”。然后分別針對(duì)上述子問(wèn)題,提出了兩個(gè)啟發(fā)式近似算法,在低復(fù)雜度的條件下實(shí)現(xiàn)了全覆蓋和高吞吐量的目標(biāo);5)針對(duì)車(chē)聯(lián)網(wǎng)基于移動(dòng)群體感知的內(nèi)容觀測(cè)調(diào)度,提出了移動(dòng)車(chē)輛群體感知框架,解決了非確定車(chē)輛軌跡、可變觀測(cè)時(shí)段和有限觀測(cè)成本條件下的車(chē)輛移動(dòng)感知調(diào)度問(wèn)題。針對(duì)非公共交通工具未來(lái)行駛路徑很難獲知的特性,推導(dǎo)得到了基于概率路徑預(yù)測(cè)模型的空間觀測(cè)覆蓋度的表達(dá)式,構(gòu)建了可觀測(cè)時(shí)段和有限成本條件下移動(dòng)車(chē)輛群體感知問(wèn)題,提出了選擇區(qū)域觀測(cè)低相關(guān)的參與車(chē)輛集合及最大化觀測(cè)時(shí)段單位成本觀測(cè)性能的車(chē)輛群體雇用方案。理論推導(dǎo)和仿真結(jié)果表明,方案提升了在非確定車(chē)輛軌跡及有限觀測(cè)成本預(yù)算條件下的空間覆蓋度性能,同時(shí)算法具有低復(fù)雜度和可擴(kuò)展性。
[Abstract]:As early as the 18th century, Adam Smith pointed out in the Wealth of Nations that "the improvement of transportation is the most effective of all improvements." With the increasingly important role of automobiles in people's daily life, the intelligent transportation system with the goal of "optimizing the use of pedestrians, vehicles and road resources" has become an important carrier of national economic development. In order to ensure the reliability, validity and stability of the information exchange of the vehicle networking, and thus enhance the accident avoidance rate of the highway traffic system, road smoothness and the level of intelligent operation, it is of great significance to study the content transmission mechanism suitable for the vehicle networking. According to the dynamic characteristics of the communication links and various types of on-board application requirements of vehicle networking, this paper studies the content transmission mechanism of vehicle networking with mobility awareness by means of model building, mechanism design, theoretical analysis and system simulation. A theoretical model of link duration in vehicle networking scenarios is proposed to solve the problem of effective mathematical characterization of wireless communication link connectivity under topology-varying networks. Based on the two-dimensional discrete Markov chain model, the temporal-spatial correlation is modeled as inter-vehicle or vehicle-to-ground correlation respectively. The theoretical analysis and simulation results show that the proposed model can effectively describe the impact of vehicle mobility correlation and shadow fading correlation on link duration under low complexity conditions; 2) for multi-hop content transmission in the no-central vehicle network; A novel beacon-free transmission protocol based on backoff counter is proposed to solve the problem that transmission efficiency and link stability should be considered in the design of transmission mechanism under dynamic topology. A novel beacon-free transmission strategy based on backoff counter is proposed, which considers the single-hop transmission distance and link duration jointly. The simulation results show that the protocol can achieve high stability and multi-hop transmission in the network environment without central vehicle, and the theoretical model can effectively describe the transmission of beacon-free protocol. Link construction delay performance; 3) For multi-hop content transmission with central vehicle interconnection, a vehicle-to-ground content upload algorithm under sparse roadside infrastructure is proposed, which solves the difficult problem of multi-hop transmission path construction considering network dynamic topology and road traffic status. A heuristic approximation algorithm is proposed for single-hop and multi-hop links respectively. The theoretical derivation and simulation results show that the algorithm can improve the stability of the transmission link and reduce the complexity of the scheme implementation. At the same time, the overall content transmission delay is shortened; 4) For the content transmission based on Multicast in the vehicle network, the resource scheduling problem under the condition of multi-vehicle user demand and dynamic network topology is proposed, which solves the problem that the layered coding video meets the requirements of both transmission coverage and high throughput in the road area. Video information is decomposed into "basic layer video scheduling sub-problem requiring full user coverage" and "extended layer view with high throughput performance under limited multicast resources" by considering the different traffic density on the road and the different resolution of video that can be played by on-board user equipment. Secondly, two heuristic approximation algorithms are proposed to solve the above sub-problems, which achieve the goal of full coverage and high throughput under the condition of low complexity. Fifthly, a mobile vehicle group awareness framework is proposed to solve the uncertain vehicle trajectory for content observation scheduling based on mobile group awareness. The problem of vehicle perceptual scheduling with variable observation period and limited observation cost is studied. In view of the fact that it is difficult to know the future path of non-public transport vehicles, the expression of spatial observation coverage based on probabilistic path prediction model is derived, and the mobile vehicle population with observable period and limited observation cost is constructed. For the perception problem, a group hiring scheme is proposed to select the vehicles with low correlation in the observation area and maximize the unit cost performance in the observation period. Low complexity and scalability.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：U495;TN929.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 孟昊;鐘章隊(duì);艾渤;;Ad Hoc網(wǎng)絡(luò)路由協(xié)議研究及其性能比較[J];信息與電子工程;2009年02期

相關(guān)博士學(xué)位論文 前3條

1 孫海峰;VANETs路由算法研究[D];電子科技大學(xué);2015年

2 何睿斯;車(chē)載網(wǎng)絡(luò)復(fù)雜場(chǎng)景下無(wú)線信道測(cè)量與建模研究[D];北京交通大學(xué);2015年

3 李利民;車(chē)聯(lián)網(wǎng)V2I通信媒體接入控制技術(shù)研究[D];哈爾濱工業(yè)大學(xué);2014年

，

本文編號(hào)：2176965