车联网中基于802.11p的MAC层车辆接入决策的研究

发布时间：2018-01-13 06:33

本文关键词：车联网中基于802.11p的MAC层车辆接入决策的研究　出处：《南京邮电大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来车载自组网已经成为了解决道路安全问题的关键技术。但是,安全应用对广播的接收率和平均的时延要求很高,专门用于车载自组网的802.11p的协议并不能很好的满足这个要求,所以研究车载自组网的媒介接入方法具有重要的意义。本文重点研究媒介接入过程的接入方法,主要工作如下:首先,本文将802.11s中的Mesh接入决策(Mesh Deterministic Access,MDA)引入到802.11p中,研究了一个考虑优先级且提前预定的接入决策协议,叫做车辆接入决策(Vehicular Deterministic Access,VeDA),保证在高负载时安全消息的低时延和高接收率。VeDA是基于802.11p/DSRC的,允许车辆在无竞争期接入到共享的信道中。VeDA方案支持两种不同优先级的安全服务(紧急安全消息和路由安全消息)并提供了严格的时延界限。VeDA将DTIM帧分割成无竞争期和竞争期,两种安全消息通过VeDA Opportunities预定接入信道,VDAOPs是无竞争期的多个时隙,而非安全消息是在竞争期以竞争的方式接入信道。仿真结果表明VeDA能有效的保证安全消息的时延和接收率,尤其是在高通信负载的情况下,在时延和接收率方面优于基于退避算法的接入方案。其次,针对VeDA方案与其他传统的方案共存接入到共享信道时的兼容性问题,本文研究了扩展的VeDA方案(Extended VeDA,EVeDA)。当非VeDA节点接入共享信道时,会使VeDA节点的时延增加,EVeDA方案通过在接入时隙VDAOP前人为的加入一个时延因子,在该时延时隙期间额外或虚假的业务会被发送,以便VeDA节点提前接入信道,减少了VeDA节点与非VeDA节点发生碰撞的几率,增加了后续的VDAOP接入信道的几率。仿真结果表明扩展方案EVeDA能有效的降低非VeDA节点的时延,从而解决因兼容性而带来的时延增加的问题。
[Abstract]:In recent years, the vehicle-mounted ad hoc network has become the key technology to solve the road safety problem. However, the security applications require very high reception rate and average delay of broadcast. The 802.11p protocol for vehicle-borne ad hoc networks does not meet this requirement very well. Therefore, it is of great significance to study the media access methods of vehicle-mounted ad hoc networks. This paper focuses on the media access process access methods, the main work is as follows: first. In this paper, the Mesh access decision in 802.11s, mesh Deterministic access MDAs, is introduced into 802.11p. In this paper, we study an access decision protocol which considers priority and is scheduled in advance. It is called vehicle Deterministic access Protocol (VeDAs). Ensure low delay and high reception rate of secure messages at high load. VeDA is based on 802.11p / DSRC. Allow vehicles to access shared channels during non-competitive periods. VeDA scheme supports two different priority security services (emergency security messages and routing security messages). A strict delay limit. Veda is provided to divide the DTIM frame into two stages: no competition period and no competition period. Two kinds of secure messages are multiple slots of non-competitive period for predetermined access channels via VeDA Opportunities. The simulation results show that VeDA can effectively guarantee the delay and reception rate of secure messages, especially in the case of high communication load. In the aspect of delay and reception rate, it is better than the access scheme based on Backoff algorithm. Secondly, the compatibility of VeDA scheme and other traditional schemes when accessing to the shared channel is discussed. In this paper, the extended VeDA scheme is studied. When the non-#en1# nodes access the shared channel, the delay of the VeDA nodes will increase. The EVeDA scheme artificially adds a delay factor to the access slot VDAOP predecessor during which additional or false traffic will be sent so that the VeDA node can access the channel in advance. The probability of collision between VeDA node and non-#en1# node is reduced. The simulation results show that the extended scheme EVeDA can effectively reduce the delay of non-#en2# nodes. In order to solve the problem of increasing delay caused by compatibility.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U495;U463.67

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