中文摘要：

针对道路交通中紧急路况消息如何通过车辆间通信快速向远方车辆传播的问题,提出一种应用于车辆自组织网络的紧急消息转播机制,设计在道路车辆密集和车辆稀少情况下的不同处理方法.车辆密集时,选择车辆节点进行转播而不是全部车辆转播,避免网络风暴;车辆稀少时,利用反向车辆进行消息转播.分析车辆稀少时转播消息所需时间,并进行实验仿真.结果表明,该方案在车辆密集时可降低丢包率,在车辆稀少时转播时延能够满足实际要求.

英文摘要：

An urgent message rebroadcast mechanism applied in vehicular ad hoc network is presented to solve the rapid transmission of traffic information to remote vehicles.It concludes different methods in dense and sparse traffic.In dense traffic,some vehicular nodes are selected to rebroadcast the message instead of by all received nodes,in order to avoid broadcast storm.In sparse traffic,opposite vehicles are selected to rebroadcast the message.Simulation and analysis results show that the the packet loss ratio in dense traffic and the re-connecting time in sparse traffic can be reduced by using this mechanism.