Link utility aware geographic routing for urban VANETs using two-hop neighbor information.

Routing in Vehicular Ad Hoc Networks (VANETs) is a challenging problem. While geographic routing protocols are preferred for VANETs due to their scalability, they are focused on finding next-hop nodes closer to the destination without considering their current load or network traffic. In addition, routing decisions based on only one-hop neighbors information might be less optimal since they do not consider the availability of further suitable nodes for forwarding. Thus, such selected next-hop nodes may become overloaded with too much traffic that exceeds their available bandwidth, and may even result in significant packet losses if no other node suitable for forwarding can be found. In this paper, we propose a novel geographic routing protocol named Geo-LU. The proposed protocol improves the routing performance by extending the local view of the network topology at the current forwarder to include two-hop neighbor information. Moreover, it utilizes our proposed link utility (LU) measure. LU considers the utility of a two-hop neighbor link by considering the minimum residual bandwidth on that link and its packet loss rate. By incorporating two-hop neighbor information and our proposed LU measure, the proposed protocol, Geo-LU, can react appropriately to the increased network traffic and to the frequent topology dis-connectivity in VANETs as confirmed by our simulation results.