CSMA based Inter-Vehicle Communication Using Distributed and Polling Coordination
CSMA based Inter-Vehicle Communication Using Distributed and Polling Coordination
复制标题
使用分布式和轮询协调的基于 CSMA 的车辆间通信
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Xiaomin Ma
中科院分区：
文献类型：
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作者：
S. Yang;H. Refai;Xiaomin Ma
智能交通系统在很大程度上依赖于车载通信(IVC)系统，通过实时传递基本信息来支持安全驾驶等。为了采取适当的行动避免碰撞，保证实时发出即将发生的碰撞警告是非常重要的。几个现有的MAC层协议被修改以解决自组织车辆环境中的实时业务；载波侦听多路访问(CSMA)就是这样的协议之一。本文在CSMA中使用不同的退避时间间隔(BTS)来实现优先级，以允许较高优先级的业务比具有中到低优先级的业务更快地访问介质。退避时间间隔与优先级成反比；优先级越高，退避时间越短。文中还提出了一种结合分布式和轮询协调功能的媒体接入控制(MAC)协议实现，以进一步增强基于BTS优先级的CSMA，并确保具有最高优先级的业务的绝对递送。通过计算机仿真评估了该协议的性能。仿真结果表明，与基于BTS的CSMA实现相比，具有最高优先级的业务在系统吞吐量和成功分组率方面都有显著提高。
Intelligent transportation systems rely heavily on inter-vehicle communication (IVC) systems to support, among other things, safe driving by relaying essential information in real time. It is very important to guarantee the delivery of an imminent collision warning in real time in order to make appropriate actions to avoid it. Several existing MAC layer protocols are modified to address real-time traffic in ad hoc vehicle environment; carrier sense multiple access (CSMA) is one such protocol. This paper implements a priority in CSMA using different backoff time spacing (BTS) to allow higher priority traffic to access the medium faster than those with medium-to-low priority. The backoff time spacing is inversely proportional to the priority; the higher the priority, the lower the backoff time. The paper also proposes a new media access control (MAC) protocol implementation that combines distributed and polling coordination functions to further enhance the BTS-priority-based CSMA and to ensure the absolute delivery of traffic with the highest priority. A computer simulation was carried out to evaluate the performance of the proposed protocol. When compared with the BTS-based CSMA implementation, the simulation results indicate significant improvements in the system throughput and successful packet rate for the traffic with highest priority.