LAUSR

Abstract Vehicular Ad-hoc Networks (VANETs) have been widely recognized as one of the most promising technologies to deliver data between vehicles to support various vehicular applications. In environments of VANETs with the feature of frequent network dynamics due to high mobility of vehicles, geographic routing is considered as an attractive approach because it can send data to a destination vehicle by using only the location information of vehicles. However, mobility of destination vehicles brings about a very challenging issue for data delivery to them because they have frequent location changes due to their continuous movements. Fortunately, the trajectory and road map information provided by on-board navigation systems of vehicles can efficiently support data delivery to them. Thus, we propose an efficient data delivery protocol that uses the trajectory information of a destination vehicle on a road map in VANETs. The proposed protocol first decides an efficient reception point on the trajectory of the destination vehicle by providing an arithmetical model based on a road map information to achieve the cost-minimized data delivery. Next, to deliver data to the efficient reception point, the proposed protocol determines an efficient data route by considering both the moving direction of the destination vehicle and the forwarding direction of data. Last, the proposed protocol provides a trajectory-based forwarding and a redirection forwarding based on data caching to cope with trajectory changes of the destination vehicle due to its moving speed and direction changes, respectively. Simulation results conducted in various environments verify that the proposed protocol achieves more efficient data delivery performances than the existing protocols.