Mobility Information and Road Topology Based Inter-vehicle Routing Protocol in Urban

Vehicular ad-hoc networks (VANETs) are special cases of mobile ad-hoc networks (MANETs) where nodes are highly mobile, so network topology is changing very fast. In VANET, vehicles move non-randomly along roads. Inter-vehicle communication is wirelessly connected using multi-hop communication without access to some fixed infrastructure. Because of the rapid movement of vehicles and the frequent topology change of VANET, link breakages occur repeatedly and the packet loss rate increases. Geographical routing protocols such as greedy perimeter stateless routing (GPSR) are known to be very suitable and useful for VANET. However, they can select stale nodes for relay nodes and generate the local maximum problem. This paper presents an inter-vehicle routing protocol based on mobility information of vehicles and digital map on city roads to solve those problems in urban area. Mobility information includes the position, velocity, and direction of vehicles. Road topology is used to obtain the location of intersections and whether it is an overpass or a dead end road. Simulation results using ns-2 show performance improvement in terms of packet delivery ratio than existing routing protocols.