Research On Surround-and-approach Routing Protocol In VANETS

Along with the recent developments in VANETs, a lot of attractive applicationshave emerged. Due to the high mobility of vehicles, a continuous and stable connectionbetween a pair of vehicles is rarely available, which makes the conventional mobile adhoc network (MANET) routing protocols inefficient. Therefore it is necessary to designan effective routing protocol to guarantee the information timely and reliabletransmission.In order to better study and design of routing protocols, routing protocol fromrouting pattern for analysis and discussion. Due to the road constraint in VANETs, therouting path in previous routing protocols is along each road. Therefore, along therouting path, the intersections are responsible for packet switching and the roads are thelinks which connect intersections. However, due to various directions at an intersectionand intermittent connectivity among vehicle nodes, the opportunistic forwarding atintersections is the challenge issue for the intersection-to-intersection routing pattern.The opportunities for packet switching at each intersection are spatiotemporally limited.Moreover, the probability for the failure of packet switching will be increasing while thenumber of intersections along the routing path is increasing. So the intersection is thebottle-neck for routing.For overcoming this obstacle, we propose a novel routing pattern, which is therouting for each packet can cross the roads without road constraint. We term it asintersection to intersection routing pattern. In this routing pattern, we adopt a pathinstead of an intersection for packet switching. The routing path includes severaladjacent intersections and roads, which can provide more opportunities than anintersection. In this pattern, multiple roads between two paths are the links for paralleldata delivery. Each data packet is routed across the paths to approach the destination. Inthis pattern, multiple roads between two paths are the links for parallel data delivery.In order to spatiotemporally control resource consumption (such as bandwidth or bufferon each node), each path is a closed circle which surrounds the destination, and we termit as the circle-to-circle routing pattern. Finally，under this routing pattern, we propose a Surround-and-Approach Routing(SAR) scheme in VANETs. We perform the simulation based on the road map ofChengdu collected from Google Earth. Based on NS2network simulation platform, weconduct the extensive simulations to evaluate the performance of SAR. Thesimulation results show that SAR can outperform the existing protocols, especiallywhen the network resources are limited.