Research On Routing Protocols And Security In Vanet

In recent years, with the rapid development of wireless communi-cation technology, VANET has been widely concerned. So, the research of VANET network routing and route security has important theoretical and practical value.VANET is a kind of vehicular network which applies Ad Hoc network technology. When applying Ad Hoc network technology to the vehicular network, we need to consider the characteristics of VANET and the specific scenarios. The city main roads and highways is a typical VANET scenario, in which the vehicles travel in opposite direction fast along straight road. However, in this scenario, the application of Ad Hoc technology has two problems:firstly, the existing clustering algorithm are not stable enough when vehicles moving in the opposite direction, secondly, bottleneck appears when applying hierarchy stature on the road, which makes existing secure routing protocols are not safe when facing black hole attacks.For the first problem, this paper proposed a direction based lowest ID algorithm (DLOWID) in chapter 3, which is improved from the lowest ID algorithm. In the new algorithm, moving direction of the vehicle is taken as one of the basis when forming clusters, and vehicles with different directions are clustered separately, so that nodes in the same cluster have relatively low speed, which makes the stability of the cluster increased. Simulation shows that in the scenes of city main road and highway, DLOWID algorithm has a better performance.For the second problem, this paper proposed a double cluster head based SAODV (DSAODV) in chapter 4, which is improved from the existing secure routing protocols SAODV. By setting two head in each cluster, DSAODV provides redundancy for the upper layer of the VANET, so the network is more effectively when facing black hole attacks. Simulation shows that network using DSAODV has a lower packet loss rate when there are cluster head drop data maliciously than network that use SAODV.