Buffer and Switch: An Efficient Road-to-Road Routing Scheme for VANETs

Vehicular Ad Hoc Networks (VANETs) are getting increasing attention from academic researchers and automotive industries. Timely and cost-efficient multi-hop data delivery among vehicles is essential for VANETs, and various routing protocols are envisioned for infrastructure-less vehicle-to vehicle (V2V) communications. Due to the road-constrained data delivery and highly dynamic topology of vehicle nodes, it's better to construct routing based on the road-to-road pattern than the traditional node-to-node routing pattern in MANETs. However, the challenging issue for the road-to-road routing in VANETs is the opportunistic forwarding at intersections. Therefore, we propose a novel routing scheme, called Buffer and Switch (BAS). In BAS, each road buffers the data packets with multiple duplicates propagation in order to provide more opportunities for packet switching at intersections. Different from conventional protocols in VANETs, the propagation of duplicates in BAS is bidirectional along the routing path. Moreover, BAS's cost is much lower than other flooding-based protocols due to its spatio-temporally controlled duplicates propagation. We conduct the extensive simulations to evaluate the performance of BAS based on the road map of a real city collected from Google Earth. The simulation results show that BAS can outperform the existing protocols, especially when the network resources are limited.