Research Of Routing Robust Of Vehicular Ad Hoc Networks In Urban Environment

Vehicular ad hoc networks(VANET) is a new direction of intelligent transport systems. VANET has its own application characteristics, and its routing protocols have bad robustness in urban traffic environment.This paper proposes a location service algorithm which performs well in urban environment,and an improved routing strategy is propsed based on the new location service algorithm. The main work and research results are presented as follows:(1)Summarize the present research of current routing protocols of vehicular ad hoc networks. Analysis the reason of routing algorithm’s bad robustness in city scene. Summarize the future direction of improveing VANET routing protocols.(2)A new location service which is called Intersection-based Hierarchical Location Service(IHLS) is proposed.The vehicle nodes locate in intersection have a good transmission condition,and these node can be location server while other node distribute the location information to them.IHLS has a hierarchical structure which have some special location server can manage other location server,the special LS is selected by the road property.IHLS have a good response and query success rate when node want to query a long distance location information.(3)Base on the IHLS,an improved routing strategy also proposes in this paper,which called Urban Traffic Aware Routing(UTAR).UTAR modify the traditional greedy forwarding to a limited intersection greedy forwarding.The new location service—IHLS can help to get real-time traffic information for sections,and can evaluation the sections’network connectivity based on the real-time traffic information. Network connectivity can be a weight when calculate the optimal path from source node to the destination node.UTAR can achieve reliable data packet transmission with source routing.(4)This paper use NS2and SUMO to simulat the real urban traffic environment. The simulation results show the improved routing protocol proposed in this paper has a stronger robustness and can better adapt to urban traffic scenes compared with some classical routing protocols algorithms.