车载自组网中基于广播的消息分发算法研究

发布时间：2018-02-26 00:33

本文关键词： 车载自组网紧急消息紧急消息广播算法交通消息分发算法　出处：《南京邮电大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着汽车数量的迅速增长和通信技术的发展，车辆安全应用越来越引起人们的关注。车载自组网（VANET）是智能交通系统中最具前景的研究领域之一，其中基于数据分发的应用需要广播技术来实现。考虑到车载自组网的特点，传统的广播算法在VANET中的性能不够理想，存在beacon消息冗余、信息传递延迟大和信息传输不稳定等问题，所以需要设计新的消息分发算法。鉴于消息分发问题的复杂性，本文根据公路场景和城市场景的不同特点提出相应的消息分发算法。首先，针对公路场景中紧急消息EMs传输延迟大和beacon消息冗余的问题，本文研究了紧急消息广播算法（EMBA，Emergency Messages Broadcast Algorithm）。该算法是对V-MCDS（VANET minimum connected dominating set）算法的改进，在beacon消息中加入车辆坐标、方向、速度和时间戳信息，利用这些信息估计车辆的位置，从而减少车辆间beacon消息交换的次数；同时EMBA扩展了EMs的中继选择范围，尽量避免采用存储转发机制，缩短EMs的传输时延。最后，，使用VanetMobiSim生成公路仿真场景，用NS2仿真器对EMBA算法仿真，结果表明，与V-MCDS算法相比，EMBA算法在减少beacon冗余，降低EMs传递时延方面性能更优。其次，针对城市场景中进行消息分发面临的分组冗余问题，本文提出一种基于节点分类的交通消息分发算法（TMDA，Traffic Messages Delivery Algorithm）。TMDA算法涉及的节点分为三类：移动节点、半移动节点和静态节点。该算法处理消息分组时，利用了半移动车辆节点的预定交通线路和运行时间，从而确保消息分组的及时转发；同时，严格按照冗余检测、位置检测、距离检测和延迟分配的步骤对消息分组进行转发控制，避免分组冗余。最后，使用VanetMobiSim生成城市仿真场景，结合NS2仿真器对TMDA算法进行仿真，并将结果与flooding算法对比。结果表明，TMDA算法在端到端时延、网络可达性和广播激发方面具有更优的性能。
[Abstract]:With the rapid increase of the number of vehicles and the development of communication technology , the application of vehicle - mounted Ad Hoc Network ( VANET ) is one of the most promising research fields in the intelligent transportation system . Firstly , the urgent message broadcasting algorithm ( EMBA , Emergency Messages Broadcast Algorithm ) is studied aiming at the problem that the transmission delay is large and the beacon message is redundant in the highway scene . The algorithm is the improvement of the algorithm of V - MCDS ( VANET minimum connected ) . The vehicle coordinate , direction , velocity and time stamp information are added to the beacon message to estimate the position of the vehicle , so as to reduce the number of beacon message exchanges between vehicles . At the same time , the EMBA extended the relay selection range of endometriosis . The simulation results show that the EMBA algorithm has better performance than the V - MCDS algorithm in reducing the beacon redundancy and reducing the transmission delay . Secondly , based on node classification , a traffic message delivery algorithm based on node classification is presented in this paper . The TMDA algorithm is divided into three types : mobile node , semi - mobile node and static node . When the algorithm processes the message packet , it uses the pre - determined traffic line and running time of the semi - mobile vehicle node to ensure the timely forwarding of the message packet . At the same time , using VanetMobiSim to generate the urban simulation scene , the TMDA algorithm is simulated by combining the NS simulator , and the result is compared with the algorithm . The results show that the TMDA algorithm has better performance in end - to - end delay , network reachability and broadcast excitation .

【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;U463.67

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