Road-Oriented Geographic Routing Protocol for Urban Vehicular Ad Hoc Networks

Geographic routing protocols have been developed for efficient V2V and V2I communications in vehicular ad hoc networks (VANETs). Existing approaches tackle challenges in urban environments such as dynamic vehicular network topology. However, in more realistic urban environments, vehicular networks are highly dynamic due to the complicated road topology and vehicular mobility, as well as shadowing caused by buildings. Therefore, traditional protocols based on the node-oriented approach could not be robust in such environments and suffer the trade-off between reach ability and scalability. In this paper, we propose a road-oriented geographic routing protocol with a road-based path definition. It integrates the sender-based forwarder suppression and receiver-based opportunistic forwarding by exploiting road map information as well as vehicular connectivity. A sender selects a road segment as a next-hop, and each qualified receiver carries out the Contention-Based Forwarding (CBF). We evaluate the proposed protocol and existing protocols through network simulations in an urban scenario with a real road map. Following simulation results, we discuss availability and remaining challenges in terms of reach ability as well as scalability.