TIGeR: A Traffic-Aware Intersection-Based Geographical Routing Protocol for Urban VANETs

In recent years, vehicular ad-hoc networks (VANETs) have received increasing interests because of their promising solutions in many urban applications. VANETs are distinguished from other kinds of ad-hoc networks, such as Mobile Ad-hoc Networks (MANETs), by high mobility and reduced communications. The topology of the network is highly time-varying due to high mobility of wireless nodes, and also joining and leaving nodes. This makes it challenging to find and maintain efficient and reliable data forwarding routes between different nodes in the network. On the other hand, equipment such as positioning systems usually exist in current vehicles which can be used to improve the efficiency of packet dissemination. This paper proposes TIGeR, a new Traffic-aware Intersection-based Geographical Routing protocol. Nodes that are at intersections make routing decision to forward packets based on both the local vehicular traffic information of different roads and the road's angle with respect to the direct vector toward the destination. Local vehicular traffic information is considered as a sign of network connectivity in a road. Simulation results show that TIGeR improves the packet delivery ratio, especially in sparse networks.