一种分布式车联网多跳信息广播协议

传统车联网通过蜂窝网进行信息传输，该传输方式延迟时间较长，难以应用于实时性高的报警信息的传输.然而，通过宽带无线网络的多跳广播方式，传输报警信息可以有效地减少延时.针对分布式车联网的特点，提出了基于地理位置、面向发送端的多跳交替广播协议AMBP(alternatingmulti hopbroadcastprotocol).首先，根据邻居车辆信息表中记录的车辆节点信息，选择下一跳中继节点.然后，利用邻居车辆信息表中的信息，计算交替信息发送阈值.最后，根据报警信息数据帧长度与交替信息发送阈值的关系，采取不同的发送策略.实验结果表明，AMBP协议降低了丢包率，减小了多跳传输延迟和延迟抖动，适合应用在分布式车联网环境.

A Multi hop Information Broadcast Protocol in Distributed Vehicular Networks

In traditional vehicular networks， most of the information transmissions were conducted by mobile cellular networks. One of the shortcomings of transmissions with cellular networks is the very long delay time， and consequently it is not applicable to real time alarm information.However， in broadband wireless networks， the end to end delay of alarm information delivered through multi hop broadcast transmission can be greatly decreased. According to the characteristics of vehicular networks， a transmitter oriented AMBP(alternating multi hop broadcast protocol)was proposed on the basis of geographical position. In the protocol， the next hop relaying node was selected by a vehicle and the alternate transmission threshold value was calculated with the neighbor information that was kept in its neighbor vehicle table. Finally， different transmission policies were taken by the proposed AMBP based on the relationships between packet size and the transmission threshold value. Experimental results showed that packet loss rate， transmission delay， and delay jitter can be successfully reduced by the proposed AMBP， which demonstrates that it is more suitable for distributed vehicular communication environment.