GPSFR: GPS-Free Geographic Routing Protocol for Intelligent Vehicles

Intelligent vehicles can improve safety by communicating critical road hazard and traffic information among vehicles in the roadway. In this paper, we propose a novel routing protocol called GPS-free geographic routing (GPSFR) for inter-vehicle communication. It does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. The proposed method focuses primarily on the complexity of rural highways and solves problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. GPSFR greedily chooses the best next hop neighbor based on a balance advance (BADV) metric that balances between proximity and link stability due to relative velocity. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage frequency to only 27% that of GPSR in the best case, and 70% in the worst case. Furthermore, the average path length of GPSFR is similar to that of GPSR about 80% of the time.