本文選題：車聯(lián)網(wǎng) + 城市道路環(huán)境��； 參考：《北京交通大學(xué)》2017年博士論文

【摘要】：隨著新一代的網(wǎng)絡(luò)技術(shù)在智能交通領(lǐng)域的應(yīng)用,車聯(lián)網(wǎng)關(guān)鍵技術(shù)的研究受到了廣泛關(guān)注。車聯(lián)網(wǎng)在緩解城市交通擁堵,提高道路使用效率,促進(jìn)交通智能化信息化建設(shè)等方面具有重要的研究意義和應(yīng)用價值。鑒于道路異常事件通常會對城市路況造成嚴(yán)重影響,設(shè)計可靠的緊急消息傳輸機制,及時有效地向目標(biāo)群體傳遞異常事件信息,將有助于提升道路交通的自我調(diào)節(jié)和應(yīng)急處理能力。車聯(lián)網(wǎng)網(wǎng)絡(luò)拓?fù)鋾S著車輛的高速移動而動態(tài)變化,并且受到路網(wǎng)拓?fù)湎拗�。而城市道路環(huán)境的特殊性將為緊急消息傳輸機制的設(shè)計帶來新的挑戰(zhàn)。本論文主要圍繞如何在城市車聯(lián)網(wǎng)環(huán)境中傳輸緊急消息開展研究工作,以提高消息傳輸可靠性保障消息傳輸效率為研究目標(biāo)。在車聯(lián)網(wǎng)中,隱藏終端問題和鏈路頻繁中斷等因素是導(dǎo)致數(shù)據(jù)包丟失,損害緊急消息傳輸可靠性的主要原因。本文首先從這兩方面出發(fā),提出了適用于城市車聯(lián)網(wǎng)的緊急消息可靠傳輸機制和轉(zhuǎn)發(fā)策略。然后,在有路邊單元(RSU)輔助的情況下,考慮如何有效利用RSU傳遞消息,并提出混合式緊急消息多跳廣播機制,解決RSU稀疏部署對消息傳輸性能的影響。本文的主要工作與創(chuàng)新點如下:(1)針對消息碰撞導(dǎo)致的數(shù)據(jù)包丟失問題,提出了一種基于道路布局感知的緊急消息可靠傳輸機制。首先,研究緊急消息發(fā)生碰撞丟失的原因,建立不飽和條件下馬爾可夫鏈模型,分析緊急消息發(fā)生碰撞的概率。然后,分析城市道路環(huán)境和布局特點,考慮多方向傳輸和障礙物遮擋等因素的影響,提出了基于布局感知的消息碰撞避免機制。該方法針對不同道路場景采用不同的傳輸策略,并解決場景變換時消息傳輸?shù)倪^渡問題。利用RBEM/CBEM握手機制避免隱藏終端問題,并且通過簡化握手過程來減少控制消息對緊急消息傳輸效率的影響。在此基礎(chǔ)上,利用上述握手機制提供的反饋信息,設(shè)計了自適應(yīng)冗余中繼節(jié)點調(diào)整機制。該方法可以根據(jù)鏈路質(zhì)量動態(tài)調(diào)整廣播冗余,進(jìn)一步提高消息傳輸可靠性。仿真結(jié)果表明,所提的可靠傳輸機制能夠提供較高的消息覆蓋率,同時維持較低的傳輸時延。(2)針對車聯(lián)網(wǎng)中通信鏈路不穩(wěn)定性導(dǎo)致的數(shù)據(jù)包丟失問題,提出了一種基于鏈路壽命預(yù)測的消息轉(zhuǎn)發(fā)機制。首先,分析城市道路場景和車輛移動對鏈路持續(xù)時間的影響,考慮車輛節(jié)點的位置、速度、方向、傳輸范圍以及有無交通燈等因素,設(shè)計了基于移動場景感知的剩余鏈路壽命預(yù)測方法。然后,權(quán)衡消息傳輸?shù)目煽啃院托?設(shè)計了兩種鏈路效用值計算方法,用來反映車輛間通信鏈路的使用價值。結(jié)合鏈路壽命預(yù)測和效用值計算,提出了新的轉(zhuǎn)發(fā)節(jié)點選擇方法,旨在選擇穩(wěn)定的通信鏈路,建立可靠的傳輸路徑,實現(xiàn)消息的可靠傳輸。仿真結(jié)果表明,該方案可以有效緩解鏈路中斷對消息傳輸?shù)挠绊?獲得較高的消息覆蓋率和傳輸效率。(3)針對如何有效利用RSU通信提高緊急消息傳輸可靠性的問題,提出了一種基于軟件定義車聯(lián)網(wǎng)的混合緊急消息多跳廣播機制。首先,將軟件定義網(wǎng)絡(luò)(SDN)技術(shù)引入車聯(lián)網(wǎng),通過部署支持SDN功能的中心控制器、混合式RSU和公交車輛,構(gòu)建基于公交車輛輔助的新型軟件定義車聯(lián)網(wǎng)架構(gòu)。其次,借助SDN控制器的邏輯集中和全局掌控能力,建立整數(shù)規(guī)劃模型,設(shè)計目的地RSU、VBT-RSU和目的地公交車選擇算法。提出通信覆蓋率、車輛遷移率、移動性熵的計算方法,合理規(guī)劃RSU的使用,減少廣播冗余。然后,針對RSU稀疏部署問題,設(shè)計了車輛間多跳廣播觸發(fā)機制,在RSU無法完全覆蓋的區(qū)域促使車輛使用車輛間通信傳遞緊急消息,提高消息的覆蓋率。最后,在車輛間通信部分提出了一種權(quán)力下放式的轉(zhuǎn)發(fā)節(jié)點選擇方法。仿真結(jié)果表明,與傳統(tǒng)ITS架構(gòu)相比,新架構(gòu)下的混合多跳廣播機制具有更高的消息覆蓋率和更低的控制器開銷。
[Abstract]:With the application of the new generation of network technology in the field of intelligent transportation, the research on the key technologies of the vehicle network has been widely concerned. The vehicle network has important research significance and application value in alleviating urban traffic congestion, improving the efficiency of road use, and promoting the information construction of traffic intelligence. The urban road conditions have a serious impact. The design of a reliable emergency message transmission mechanism and the timely and effective transmission of abnormal event information to the target group will help to improve the self-regulation and emergency handling capacity of road traffic. The network topology of the vehicle network will change dynamically with the high-speed movement of the vehicle, and will be restricted by the topology of the road network. The particularity of city road environment will bring new challenges to the design of emergency message transmission mechanism. This paper focuses on how to transmit emergency messages in the network environment of urban vehicles to carry out research work to improve the efficiency of message transmission reliability guarantee message transmission. The main cause of the packet loss is the loss of data packet and the reliability of the emergency message transmission. First, this paper, starting from these two aspects, proposes an emergency message reliable transmission mechanism and forwarding strategy suitable for urban vehicle networking. Then, under the condition of the roadside unit (RSU), we consider how to use RSU to transmit messages effectively, and propose a method to deliver the message effectively. A hybrid emergency message multi hop broadcast mechanism is proposed to solve the impact of RSU sparse deployment on message transmission performance. The main work and innovation points of this paper are as follows: (1) to solve the data packet loss caused by message collision, an emergency message transfer mechanism based on road layout awareness is proposed. First, the study of emergency message collision is carried out. The cause of the loss is to establish a Markov chain model under unsaturated conditions, analyze the probability of the collision of emergency messages. Then, analyze the urban road environment and layout characteristics, consider the influence of multi direction transmission and obstacle occlusion, and propose a collision avoidance mechanism based on layout awareness. This method is used for different road scenes. Using different transmission strategies and solving the transition problem of message transmission when the scene is transformed. Using the RBEM/CBEM handset to avoid the hidden terminal problem, and reducing the influence of the control message to the efficiency of the emergency message transmission by simplifying the handshake process. On this basis, the adaptive feedback information provided by the handset system is designed. Redundant relay node adjustment mechanism. This method can dynamically adjust broadcast redundancy according to link quality to further improve the reliability of message transmission. The simulation results show that the proposed reliable transmission mechanism can provide high message coverage and maintain low transmission delay. (2) the communication link instability in the vehicle network is caused by the instability of the communication link. A message forwarding mechanism based on link life prediction is proposed. Firstly, the impact of urban road scene and vehicle movement on link duration is analyzed, and the location, speed, direction, transmission range and traffic lights of vehicle nodes are considered, and the residual link life based on mobile scene perception is designed. Then, weighing the reliability and efficiency of message transmission, two methods of link utility value calculation are designed to reflect the use value of communication links between vehicles. A new method of forwarding node selection is proposed, which is designed to select a stable communication link and establish a reliable transmission path by combining link life prediction and utility value calculation. The simulation results show that the scheme can effectively alleviate the impact of link interruption on message transmission and obtain high message coverage and transmission efficiency. (3) a hybrid emergency message based on software definition of vehicle networking is proposed in view of the problem of how to effectively utilize RSU communication to improve the reliability of emergency message transmission. Multi hop broadcasting mechanism. First, software definition network (SDN) technology is introduced into the network of vehicles. By deploying a central controller that supports SDN functions, hybrid RSU and bus vehicles, a new software definition vehicle network architecture based on bus vehicle assistance is constructed. Secondly, the integer programming model is established by using the logic centralization of the SDN controller and the overall control ability of the SDN controller. Type, design destination RSU, VBT-RSU and destination bus selection algorithm. Put forward communication coverage, vehicle mobility, mobility entropy calculation method, rationally plan the use of RSU and reduce broadcast redundancy. Then, aiming at the problem of RSU sparse deployment, a multi hop broadcast trigger mechanism between vehicles is designed to promote vehicles in the area where RSU is not fully covered. In the end, a decentralized forwarding node selection method is proposed in the communication part of the vehicle. The simulation results show that the hybrid multi hop broadcast mechanism under the new architecture has higher message coverage and lower controller overhead compared with the traditional ITS architecture.

【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TN929.5;U495

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本文編號：1822209