Routing Protocols for Vehicular Ad Hoc Networks in Rural Areas

Research on vehicular ad hoc networks has focused mainly on efficient routing protocol design under conditions where there are relatively large numbers of closely spaced vehicles. These routing protocols are designed principally for urban areas with high node density and fully connected networks and are not suitable for packet delivery in a sparse, partially connected VANET. In this article, we examine the challenges of VANETs in sparse network conditions, review alternatives including epidemic routing, and propose a border node-based routing protocol for partially connected VANETs. The BBR protocol can tolerate network partition due to low node density and high node mobility. The performance of epidemic routing and BBR are evaluated with a geographic and traffic information-based mobility model that captures typical highway conditions. The simulation results show that under rural network conditions, a limited flooding protocol such as BBR performs well and offers the advantage of not relying on a location service required by other protocols proposed for VANETs.