HarpiaGrid: A Reliable Grid-based Routing Protocol for Vehicular Ad Hoc Networks

Vehicular ad hoc network (VANET) is a research field attracting growing attention. Current routing protocols in VANET usually use geographic information to forward data packets to the destination. Since geographic routing is stateless, during routing forwarding, route recovery processes would be continuously initiated if any topology hole exists, resulting in serious performance degradation. In addition, if vehicle density is low in the network, there might not be vehicles available to deliver the packet. This paper proposes HarpiaGrid, a reliable grid-based routing protocol for VANETs. The protocol utilizes in-car navigators to produce geographically logical routing paths, effectively trades route discovery network overhead with insignificant computation time. In addition, by taking advantage of the information provided by gridded geographic data, transmissions are made more efficient. Moreover, in the route maintenance, a fault-tolerance procedure is designed to avoid dead paths. Simulations were conducted, and the results demonstrated that the proposed scheme is indeed more efficient and reliable than other protocols.