Abstract
With the high demand of mobile Internet services, vehicular ad hoc networks (VANETs) have become a promising technology to enable vehicular Internet access. However, the development of a reliable routing protocol to route data packets between vehicles and infrastructure gateways is still a challenging task due to the high mobility and frequent changes of the network topology. The conventional position-based routing (PBR) in VANETs can neither guarantee the existence of a routing path between the source and the destination prior to the transmission nor provide connection duration information, which makes it unsuitable to route Internet packets. In this paper, we propose a novel infrastructure-based connectivity aware routing protocol called i CAR-II that enables multihop vehicular applications, as well as mobile data offloading and Internet-based services. iCAR-II consists of a number of algorithms triggered and run by vehicles to predict local network connectivity and update location servers with real-time network information, in order to construct a global network topology. By providing real-time connectivity awareness, iCAR-II improves the routing performance in VANETs by dynamically selecting routing paths with guaranteed connectivity and reduced delivery delay. Detailed analysis and simulation-based evaluations of iCAR-II demonstrate the validity of using VANETs for mobile data offloading and the significant improvement of VANETs performance in terms of packet delivery ratio and end to end delay.