Safety Message Propagation Using Vehicle-Infrastructure Cooperation in Urban Vehicular Networks

A soaring number of vehicles in modern cities bring in complicated urban transportation and severe safety risks. After a traffic accident occurs, how to quickly disseminate this alert to other vehicles is very important to avoid rear-end collision and traffic jam. Existing studies mainly use the vehicles travelling in the same direction as the collision vehicles to forward safety messages, which strictly limit the performance improvements. In this paper, we propose a safety message propagation scheme using vehicle-infrastructure cooperation in urban vehicular networks, named SMP. On straight roads, the opposite-lane front vehicles help to relay data when no further collision-lane back vehicles exist, while at intersections, the deployed roadside units create new safety messages with updated dissemination parameters and distribute them in the upstream lanes. The collaboration of vehicles in two directions and roadside units enhances the performances of safety-related applications. Besides, three checking policies are designed to avoid transmission failures and hence save network resources. Simulation experiments show that SMP achieves a high reception ratio and a short propagation delay.