A greedy next-hop selection module for vehicular ad-hoc network routing using the A* algorithm method

Abstract

The potentials of traffic data sensing and vehicle-to-vehicle (V2V) communications for advancing traffic safety and efficiency at low costs is stirring the IEEE 802.11p vehicular ad-hoc network (VANET) type. However, the VANET milieu of incessantly high mobility nodes renders contemporary routing protocols ineffective in it. The development efforts of an appropriate protocol for VANET routing have narrowed towards the position-aware greedy scheme, which involves making next-hop forwarding choices of a neighbour that is geographically closer to destination continually. Forwarding techniques in MANET/VANET that use the geographic greedy scheme to make next-hop selections include MFR, NFP, CR, NC and Greedy. We propose an alternative technique for packets forwarding in VANET. We designed the S* next-hop selection method, based on the A* path search algorithm. In addition, we developed a next-hop search-space limiting mechanism using the GLAR protocol’s baseline and DIST (distance) concepts. We utilised the EstiNet simulator to model and evaluate our designs in terms of unicast outgoing and incoming packets delivery success rates. The performance graphs remarkably show the S* technique demonstrating better results than the common Greedy technique in VANET routing. We further realized a phenomenon of either the S* or the Greedy method functioning best during certain periods of the packets forwarding duration. These alternating efficacies suggest prospects for the development of some hybridized-greedy technique for a more optimal next-hop selections method in VANET routing. The results also demonstrated the DIST mechanism’s impact on packets delivery rates. Besides, we simulated and show the inefficiency of table-driven routing methods in VANET as compared to the dynamic greedy and geographic forwarding type.