A Research On Vanet Data Transmission Mechanism Based On Network Topology Dynamics Analysis

Intelligent Transportation Systems has become a global research issue, and as an important basis for intelligent transportation systems vehicular network is becoming more and more important in this context. With the rapid development of wireless network technology, VANET (Vehicular Ad-hoc network) as one of the main directions of research, has been paid much more attention day by day. Vehicular Ad hoc network is a special kind of MANET (Mobile Ad-hoc network, MANET),VANET is different from ordinary MANET characteristics including vehicles moves fast causing topology changes rapidly, vehicle density changes causing VANET easily interrupted, vehicle movement is limited by the topology of the road causing holes in VANET topology. These characteristics of VANET has brought great challenges for the transmission mechanism design under VANET environment.Vehicular Ad-hoc network is not a static network, topology changes with the joining and leaving of vehicles, one key issue to the development of vehicle communication and service protocols is to understand the characteristics of the vehicle communication graph. This paper, based on open TAPASCologne project data of URBANET team of the University of Lyon, studies the VANET topology characteristics of several metrics in large-scale scenario, by the method of complex network analysis. This paper explores the important nodes for routing and data distribution in the connection level, analyzes VANET topology of large-scale urban scene in network connectivity and stability as well as the importance of network nodes. In addition, this paper proposes a routing strategy which combines topology knowledge and geographic position. This routing strategy is based on the idea of greedy forwarding considering the limit of road topology of urban scene, data is forwarded segment by segment; the location information and the local centrality metric are combined together to choose the target node; the opportunity forwarding is used to select more candidate nodes in order to improve the reliability of data transmission; static nodes are deployed at the intersection to assist in data transmission as a result reducing interference of obstacles. Finally, simulation software NS2 is used to verify the proposed routing policy combining topology knowledge and geographic position, to verify the routing policy advantages in data reception rate, transmission delay, network overload and other aspects.