Enhanced Intersection-Based Perimeter Geo-Routing in Urban Vehicular Ad-Hoc Networks

The ongoing research in the field of vehicular communication towards cooperative Intelligent Transport Systems (ITS) tries to tackle the ever increasing road traffic problems. In urban Vehicular Ad-hoc Networks (VANET), network disconnections happen frequently as a result of fast movement of vehicles, road layout constraints, and shadowing effects caused by buildings. Therefore, one of the key factors to successfully establish VANETs, is a routing protocol, which can fulfill the Quality-of-Service (QoS) required by ITS's promised applications, e.g., traffic management, road safety and comfort. Because of the simplicity, efficiency and scalability of geo-routing protocols, they suit for VANETs. The family of greedy perimeter geo-routing protocols became a considerable solution for VANETs. Although enhancements to GPSR (Greedy Perimeter Stateless Routing) has been proposed, still there are shortcomings, which needs to be eliminated, to have geo-routing at its best. In this paper, EIPG (Enhanced Intersection-based Perimeter Geo-routing) is proposed for urban VANETs. EIPG inherits the restricted greedy forwarding of GpsrJ+ but employs a new intersection-based perimeter forwarding in order to avoid the problem of Wrong Street Estimation (WSE). Based on our profound simulation study, EIPG shows a significant improvement in comparison to GpsrJ+, in terms of Packet Delivery Ratio (PDR), end-to-end delay, and network overhead. EIPG also requires only the information of single-hops, i.e., the direct neighbor vehicles, to avoid the unnecessary overhead caused by the extra information included in the beacon messages of GpsrJ+ and be more compatible with the standard Cooperative Awareness Messages (CAM).