An efficient vehicle-heading based routing protocol for VANET networks

Internetworking over Vehicle Ad-hoc Networks (VANETs) is getting increasing attention from all major car manufacturers. The design of effective vehicular communications poses a series of technical challenges. Guaranteeing a stable and reliable routing mechanism over VANETs is an important step towards the realization of effective vehicular communications. In current ad-hoc routing protocols, the control messages in reactive protocols and route update timers in proactive protocols are not used to anticipate link breakage. They solely indicate presence or absence of a route to a given node. Consequently, the route maintenance process at both protocol types is initiated only after a link breakage event takes place. This paper argues the use of information on vehicle headings to predict a possible link breakage event prior to its occurrence. Vehicles are grouped according to their velocity vectors. When a vehicle shifts to a different group and a route, involving the vehicle, is to be broken, the proposed protocol searches for a more stable and "more durable" route that includes vehicles from the same group. The proposed scheme is dubbed Velocity-Heading based Routing Protocol (VHRP). Whilst the proposed scheme can be implemented on any existing routing protocol, the paper considers the case of VHRP over Destination-Sequenced Distance Vector (DSDV) routing protocol. The performance of the scheme is evaluated through computer simulations. Simulation results indicate that knowledge on the vehicles' heading adds major benefits to routing in terms of reducing the number of link breakage events and increasing the end-to-end throughput.