车载自组织网络数据分发技术研究

发布时间：2018-07-10 11:47

本文选题：车载自组织网络 + 广播　；参考：《浙江工业大学》2012年博士论文

【摘要】：车载自组织网络(Vehicular ad-hoc network, VANET)是智能交通系统研究领域中非常有前景的一个方向,已经成为无线网络和智能交通系统研究的一大热点,受到众多科研机构和学者的重视。由于传感技术的发展以及未来智能交通应用的多样性,VANET中信息量非常大,且各种信息的服务质量需求迥异。例如,在防追尾警告、交叉路口碰撞预警等安全应用中,需要可靠、及时地把消息广播给相关的车辆,在商业电子广告发布、停车位预订、信息共享与查询等非安全应用中,需要高效率地把消息传输到特定的地理区域。所以,数据分发是VANET中一个十分基础而又重要的问题。由于车辆节点高速移动、密度不均、通信场景复杂多变的特点,导致VANET的拓扑结构高度动态、信道极其不稳定和不可靠。在VANET中进行稳定高效的多跳数据传输是一个很大的挑战,传统移动自组织网络的数据分发技术并不适用于VANET.如何在VANET中提高网络通信的性能,根据不同的应用需求进行有效的数据分发,保障网络提供的服务质量,是学术界和工业界一直关注的研究热点。针对VANET高度动态且不可靠的特点,本文既研究了紧急数据快速分发的广播协议设计,同时也考虑了非紧急数据的高效率分发问题。本文的研究工作取得的创新性成果如下：1、针对VANET拓扑快速变化、信道质量不稳定的特点,提出了发送端指派的机会广播协议SOBP (Sender-designated Opportunistic Broadcast Protocol),并推导了机会广播的期望重传次数,引入重传机制加强广播传输的可靠性,解决了VANET广播中存在的两个新问题：慢反应问题和局部广播风暴问题。SOBP广播数据时,根据VANET网络拓扑带状分布的特点由发送端利用方向和距离作为度量,指定固定数目的候选转发中继并预先分配优先级来控制转发时机。仿真结果表明,SOBP固定了候选转发中继的数目,大大节省了网络带宽,注入网络的数据量较少,成功解决了广播风暴问题以及慢反应问题和局部广播风暴问题,提高了广播信息分发的可靠性。 2、针对广播时延要求严格的VANET安全应用,提出了自适应的多候选中继机会广播协议MCROB (Multiple Candidate Relays Opportunistic Broadcast)。在分析机会广播传输速度的基础上,提出了新的候选转发中继选择度量：期望传输速度ETS (Expected Transmission Speed)。分析并推导了数据包传递率PDR (Packet Delivery Ratio),根据PDR和ETS提出了一个启发式的优先级调度规则来选择候选转发中继集合。同时提出了一个自适应于网络节点密度和流量负载的候选转发中继协作时延估计算法,动态设定中继节点重传(或转发)计时器。仿真分析表明,MCROB有效减少了广播传输时延,性能优于现有广播协议,满足广播信息对实时传输的需求。 3、针对VANET信道的不可靠和时延抖动敏感数据传输的要求,提出了下三角的渐进编码方法,并在此基础上提出了一种新的基于动态滑动窗口的网络编码传输策略。该策略的编码窗口根据不同的网络环境动态滑动,利用随机线性网络编码技术有效地提高了端到端的吞吐,同时利用下三角的渐进编码方法平滑了数据包在接收端的解码时间间隔。仿真实验表明,此传输策略比传统的分代网络编码策略具有更高的吞吐量和更小的时延抖动,更适合流媒体等时延抖动敏感的数据流传输。 4、针对VANET中基于区域位置的服务,提出了本地响应服务LRS (Local Response Service)的概念,并以此为基础提出了一种基于网络编码技术的区域数据分发策略。LRS的主要思想是服务区域内的任意一个节点请求,都可以由其邻居节点提供服务。该策略根据这个思想把待分发的内容通过随机线性网络编码技术进行编码,使之具有无差异性和地位对等的特点,然后把这些数据随机地分发到服务区域内的各个移动车辆节点中并缓存以作回应请求之用。为了计算响应请求时所需传输的数据量,提出了邻居数据有效性的概念来判断一个节点是否是合格的服务节点,避免了无效传输,节省了网络带宽。同时还提出了缓存数据更新策略,改善了缓存节点响应服务的有效性。仿真实验表明,LRS策略避免了多跳传输,有效降低了数据的分发延迟,改善了整个系统的消息传递率。
[Abstract]:Vehicular ad-hoc network (VANET) is a very promising direction in the research field of intelligent transportation system. It has become a hot spot in the research of wireless network and intelligent transportation system. It has been paid much attention by many scientific research institutions and scholars. The development of sensing technology and the diversity of future intelligent traffic applications In nature, the amount of information in VANET is very large, and the quality of service of various information is very different. For example, in security applications such as anti rear end warning, intersection collision warning and other security applications, it needs to be reliable, timely broadcast messages to relevant vehicles, in non safe applications such as commercial electronic advertising, parking space reservation, information sharing and inquiry, and so on. Data dissemination is a very basic and important issue in VANET.
Due to the high speed movement, uneven density of vehicle nodes and complex and changeable communication scenes, the topology of VANET is highly dynamic and the channel is extremely unstable and unreliable. It is a great challenge to carry out stable and efficient multi hop data transmission in VANET. The data distribution technology of traditional mobile self organizing network is not suitable for VANET., such as How to improve the performance of network communication in VANET and to distribute effective data according to different application requirements and ensure the quality of service provided by the network is a hot research focus in the academic and industrial circles.
In view of the high dynamic and unreliable characteristics of VANET, this paper not only studies the broadcast protocol design of rapid distribution of emergency data, but also takes into account the efficient distribution of non emergency data. The innovative achievements of this research work are as follows: 1, the transmission of VANET topology and the characteristics of channel quality instability are proposed. The opportunity broadcast protocol SOBP (Sender-designated Opportunistic Broadcast Protocol) is assigned, and the expected retransmission times of opportunity broadcasting are derived, the retransmission mechanism is introduced to strengthen the reliability of broadcast transmission, and the two new problems existing in VANET Broadcasting: slow response question and local broadcast storm problem.SOBP broadcast data, root, are solved. According to the characteristics of the VANET network topology, the characteristics of the banded distribution are measured by the direction and distance of the sending end, designate a fixed number of candidate forwarding relays and pre assign the priority to control the forwarding opportunity. The simulation results show that the number of candidate forwarding relays is fixed by SOBP, and the network bandwidth is greatly saved, and the amount of data injected into the network is less, successful. The problems of broadcast storm, slow response and local broadcast storm are solved, and the reliability of broadcast information distribution is improved.
2, an adaptive multi candidate relay opportunity broadcast protocol MCROB (Multiple Candidate Relays Opportunistic Broadcast) is proposed for the VANET secure application with strict broadcast delay. Based on the analysis of the transmission speed of the opportunity broadcast, a new candidate forwarding relay selection measure is proposed: the expected transmission speed ETS (Expected Transmis). Sion Speed). Analyze and deduce packet transfer rate PDR (Packet Delivery Ratio). Based on PDR and ETS, a heuristic priority scheduling rule is proposed to select candidate forwarding relay sets. At the same time, an adaptive forwarding relay cooperation delay estimation algorithm is proposed, which is adaptive to network node density and traffic load. The relay node retransmission (or forwarding) timer. The simulation analysis shows that MCROB effectively reduces the broadcast transmission delay, and the performance is better than the existing broadcasting protocol, and meets the demand of the broadcast information for real-time transmission.
3, aiming at the requirement of unreliable and time-delay jitter sensitive data transmission in VANET channel, a progressive coding method of lower triangle is proposed. On this basis, a new network coding transmission strategy based on dynamic sliding window is proposed. The coding window of this strategy is dynamically sliding according to different network environment and using random linear network coding. The technology effectively improves the end-to-end huff and puff, and smoothes the decoding time interval of the data packet at the receiving end by the progressive encoding method of the lower triangle. The simulation experiment shows that the transmission strategy has higher throughput and smaller delay jitter than the traditional generation network coding strategy, and is more sensitive to the delay jitter of the streaming media. Data stream transmission.
4, the concept of local response service LRS (Local Response Service) is proposed for service based on regional location in VANET. Based on this, the main idea of a regional data distribution strategy based on network coding technology,.LRS, is an arbitrary node request in the service area, which can provide service by its neighbor nodes. The strategy is based on this idea to encode the content to be distributed through the random linear network coding technology, so that it has the characteristics of non difference and status equivalence, and then randomly distribute these data into each mobile vehicle node in the service area and cache it for response request. In order to calculate the response request, it is necessary to calculate the response request. The amount of data transmitted, the concept of neighbor data validity is proposed to determine whether a node is a qualified service node, avoiding invalid transmission and saving network bandwidth. At the same time, a cache data updating strategy is proposed, which improves the effectiveness of the cache node response service. The simulation experiment shows that the LRS strategy avoids multi hop transmission and is effective. The data distribution delay is reduced, and the message passing rate of the whole system is improved.
【学位授予单位】：浙江工业大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：TN929.5

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