Load Aware Routing with Delay Threshold for Vehicular Ad Hoc Networks

It is being envisaged that a wide variety of applications can be running on vehicular ad hoc networks (VANETs) in the near future. The coexistence of these applications suggests that they will be competing for the use of the wireless medium. That easily leads to severe congestion and even “hotspot” problem in high traffic density urban areas, and results in the failure of time-critical applications. To address this issue, we propose two carry-and-forward schemes called LARD-Greedy and LARD-Optimal respectively that attempt to deliver packets along the path with optimal performance. The proposed algorithms leverage local or global knowledge of traffic statistics to choose the path with optimal performance, and rationally alternate between the Carrying and Multihop Forwarding strategies according to the current load status in order to avoid congestion. Experimental results based on a real city map show the proposed solutions reach very good performance in terms of packet delivery ratio and delay.