Link stability analysis in VANETs using topology based protocol

Routing in VANET is a challenging task as the nodes remain highly mobile and there is frequent disconnection and reconnection of node links. Estimating link time to remain connected with the nodes is therefore an important task in VANETs as various routing algorithms can drastically degrade in performance due to change in link status. Various algorithms proposed earlier provide the link estimation but almost all are dependent on specialized GPS to locate position of nodes. Position based routing protocols are becoming popular due to advancement and availability of GPS devices but they can be less accurate as their accuracy is only up to 5 to 10 meters in outdoor environments. In addition, a GPS is not applicable in locations where no line of sight exists, e.g., in a tunnel. The other drawback of GPS is that it cannot locate a vehicle which is inside big campuses like universities and airports. In this paper we propose a mechanism that estimates the link stability time without making use of GPS. The routing decisions are taken based upon the link time and the direction of the nodes. Our simulation results prove the purpose of using this approach in VANETs.