A Routing Protocol Suitable For Warning Message Propagation On The Highway

In recent years, traffic accidents on the highway are increasing with the rapid development of highway, so it is necessary to develop an effective traffic warning system for accidents. At present, the traffic warning systems for vehicular communication system are mainly based on the wireless ad hoc network, and restricted in the actual application,because there still have some problems on the routing protocols for ad hoc traffic warning system,This paper is begun with the introduce of mobile ad hoc network(MANET) and its main features, logical structure and application fields; and then followed by vehicular ad hoc network(VANET)-an ad hoc network application in Intelligent Transportation Systems(ITS)field, and its brief advantages and disadvantages.In order to improve the performance of the original routing protocol in VANET, this paper introduces an improved routing protocol combined with AODV protocol and LAR protocol, HWSW(acronym for highway safety warning protocol),which is suitable for effective delivery of warning information in highway scenarios. HWSW routing protocol includes two key points of improvement. The first improvement is that the HWSW routing protocol adopts two propagation modes according to the different message type; the second improvement is that the warning message takes broadcasting propagation if the first hop is not farther than 1000 m, and takes hop by hop propagation if the first hop is farther than 1000 m. It provides the effective guarantee on the safety of highway traffic to reduce the propagation delay of VANET networks, improve the efficiency of the protocol, and ensure early warning information timely and effective delivery through VANET warning system.In the end, the HWSW protocol is compared with the AODV protocol by using Vanet Mobi Sim traffic simulation and NS2 network simulation. The simulation result of six key network performance parameters is obtained by comparison with AODV protocol. It is verified that the HWSW has good performance in reducing propagation delay in highway scenarios, reducing routing overhead and improving packet delivery ratio and so on.