Study On Survivability Technology Of Vehicular Ad Hoc Networks

With the prevalence of vehicles and the constant development of mobile ad hoc network (MANET) techniques, vehicular ad hoc network (VANET), as one of the most crucial parts of Intelligent Transport Systems (ITS), has gradually become a new research field in MANET. VANET consists of vehicles with varied mobility, and is a especial kind of MANET. VANET has a fine application prospect in traffic information warning, driving abidance, inter vehicular communication, internet accessing, and so on.Nowadays, the researches focus on the MAC protocols, routing protocols, network securities and so on. However, the performance of VANET has gradually attracted attention of both academe and industries. VANET, as a wireless network, is vulnerable due to its high mobility and large scale of network. Consequently, it is very important to study how to maintain the continued provision of services, which means guaranteeing the survivability of VANET when suffering from varied threatens.Aiming at the survivability of VANET, this thesis developed a survivability model for VANET, and studied the routing techniques for improving the survivability of VANET.Firstly, the applications and architectures of VANET were introduced, and its characteristics were analyzed, too.Secondly, according to its characteristics and applications, the factors in the survivability of VANET was analyzed, the survivability of VANET was defined, the services, threatens, and strategies of VANET were analyzed, and the model of average survivability based on Markov chain was developed. Finally, the correctness verification work of the model was also done by simulations. Both the theory and simulation results showed that improving the quality of communication of VANET could efficiently enhance the survivability.Thirdly, the existing routing protocols for VANET were introduced, then based on the existing routing protocols—AODV and VHRP, a routing protocol—velocity based position predictive routing protocol(VPRP) was put forward, which was more suit for VANET in city scenarios. Simulation results showed that it improved routing performance. Without the increase of packet loss rate, it further reduced average delay; consequently, it ensured the timely delivery of network services.Because NS2 couldn't generate the traffic scenarios which the simulation needed, a traffic generator for city scenarios was designed and implemented, whose outputs was for NS2.