Propagation Mechanism Of Highway Safety Message Based On VANETt

In recent years, construction of the highway has become an important index for measuring the regional economic level. And people’s daily life take more closely associated with the development of highway. So highway safety issue has become the focus of public concern and the popular topic in traffic safety research field. Meanwhile, the rapid development of the Intelligent Transportion System (ITS) has provided more advanced technology support for the research of highway traffic safety.The purpose of this paper is to introduce Vehicle Ad Hoc Network (VANET) technology of ITS into the highway safety warning system research. Through an analytical investigation about four typically VANET routing protocols, DSDV, DSR, AODV and LAR, to summarize the advantages and disadvantages of these four routing protocols under different scenarios. So that base on the analysis to propose a design of establishing a new routing protocol for highway safety warning system.Subsequently, this paper takes another analytical investigation about Node Mobility Model and adopts VanetMobiSim traffic simulation tools to establishing the highway traffic simulation environment. Then take an example to analysis highway vehicles safety distance model to further confirm the signification of this research.The core content of this paper is designing an improved AODV routing protocol, named HWIM (Highway scenarios for Warning and Inquire Message propagate) routing protocol, for highway vehicle safety warning propagation system. HWIM adopts three improved methods based on AODV, according to message type to distinguish the send direction of route packets, to shield the message transmitting of interference node by vehicle-node driving direction, set a dynamic forwarding angle for middle node to restrict flooding broadcast. Also from the three methods to reduce the VANET delay and increase the efficiency of the protocol, then to realize the insurance of highway vehicle safety warning.Finally, this paper used two simulation tools, VanetMobiSim and NS2, to make simulation test on HWIM routing protocol. With analyzing test result which has been compared with AODV, to confirm that HWIM has more advantages in some important ways for reducing delays and route overhead, and increasing packet delivery ratio. Meanwhile, this paper presented the deficiencies of this study and the outlook for the next phase of the research.