Improved GPSR-SD Routing Protocol for VANET

Routing is the key technology of a vehicular ad hoc network (VANET). On the basis of the high mobility of nodes and the vast frequent changes of the network topology of ad hoc networks, this study proposed an improved greedy perimeter stateless routing with speed-density direction (GPSR-SD) routing protocol, which is based on the GPSR protocol. The proposed routing protocol is combined with the speed-density model to estimate the density information of a vehicle node traveling on a road. It considers the traveling speed of the vehicle node and the density of the road to select the next hop forwarding node and improve the selection of the forwarding node, thereby increasing communication reliability. The proposed routing protocol can effectively reduce the hole phenomena caused by the movement of the node, improve the average packet delivery ratio, and reduce average end-to-end delay. Simulation results of the NS2 platform indicate that GPSR-SD performs well.