车载自组织网络下的介质访问控制协议研究

发布时间：2018-05-09 13:31

本文选题：车载自组织网络 + 介质访问控制　；参考：《南京邮电大学》2016年硕士论文

【摘要】：车载自组织网络(Vehicular Ad-hoc Network,VANET)作为智慧交通系统的重要组成部分,能够为用户带来安全舒适的行车体验。而VANET的网络性能取决于介质访问控制(Medium Access Control,MAC)协议。由于VANET网络具有车辆移动速度快、网络拓扑快速变化等特点,使得原有的IEEE 802.11p协议中基于载波侦听多路访问/冲突避免的MAC协议无法满足安全应用的要求。因此,如何针对VANET的特点来改进现有的MAC协议,使其满足安全应用对广播消息的平均到达时延和接收率的要求是十分必要的。本文针对以上问题进行深入探究,主要工作如下:首先,建立车载自组织网络中具有优先级的安全消息传输性能分析模型,通过该模型分析出状态消息存在的情况下紧急消息的平均传输时延;仿真结果验证了该模型的正确性,该模型对选取合适的网络参数来减小紧急消息的传输时延及进一步研究VANET的其他性能具有一定的参考价值。其次,针对IEEE 802.11p的MAC层协议以及现有的改进协议在车辆密度较高的情况下性能较差的问题,研究了一种基于多数据速率的MAC协议(Multiple-Data-Rate MAC,MDR-MAC)。该协议通过引入多数据速率的方式减小了消息的传输时间,降低了网络拥塞;通过集中式时隙分配的方式减小了消息之间的碰撞,从而保证了信标消息的有效广播;仿真结果表明该协议在信标消息的接收率和平均到达时延方面的性能均有所提升。最后,为进一步优化紧急消息传输的有效性和可靠性,本文研究了紧急消息的时隙预约机制和协作传输机制。时隙预约机制通过减小紧急消息接入信道的时延,提高了紧急消息的传输有效性;协作传输机制通过识别接收紧急消息失败的节点、选择辅助节点、重传消息这一过程提升了紧急消息的接收率,从而提高了紧急消息的传输可靠性。仿真结果表明该机制能够保证紧急消息的实时可靠传输。
[Abstract]:As an important part of intelligent transportation system, vehicle Ad-hoc Network (VANET) can bring users a safe and comfortable driving experience. The network performance of VANET depends on medium Access Control (MAC) protocol. Because of the fast moving speed of vehicle and the rapid change of network topology, the MAC protocol based on carrier listening multiple access / collision avoidance in the original IEEE 802.11p protocol can not meet the requirements of security applications. Therefore, it is necessary to improve the existing MAC protocol according to the characteristics of VANET to meet the requirements of the security applications for the average delay of arrival and reception rate of broadcast messages. The main work of this paper is as follows: firstly, the security message transmission performance analysis model with priority in vehicular ad hoc network is established. Through this model, the average transmission delay of emergency message in the presence of state message is analyzed, and the simulation results verify the correctness of the model. This model has some reference value for selecting appropriate network parameters to reduce the transmission time of emergency messages and to further study the other performance of VANET. Secondly, aiming at the problem that the MAC layer protocol of IEEE 802.11p and the existing improved protocol have poor performance in the case of high vehicle density, a MAC protocol based on multi-data rate (MAC), Multiple-Data-Rate Marc, is studied. The protocol reduces the transmission time and network congestion by introducing multi-data rate, reduces the collision between messages by centralized slot allocation, and ensures the effective broadcast of beacon messages. The simulation results show that the performance of the proposed protocol is improved in terms of the reception rate and the average arrival delay of the beacon message. Finally, in order to optimize the efficiency and reliability of emergency message transmission, the slot reservation mechanism and cooperative transmission mechanism of emergency message are studied in this paper. Slot reservation mechanism improves the transmission efficiency of emergency message by reducing the delay of emergency message access channel, and cooperative transmission mechanism selects auxiliary nodes by identifying the node that has failed to receive emergency message. The process of retransmitting messages improves the receiving rate of emergency messages and improves the transmission reliability of emergency messages. Simulation results show that this mechanism can guarantee the real-time and reliable transmission of emergency messages.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.5;U495

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