Multi-Path Routing Protocol for Vehicular Ad-hoc Networks

In this paper, we explore the impact of the vehicular density on routing protocol design for vehicular ad hoc networks (VANET). Specifically, we focus on multi-path-based routing protocols designed for vehicular communications in urban areas. We find that the vehicular density greatly impacts the routing in urban areas. However, low vehicular density scenarios have not been well treated in the existing routing protocols. In this paper, we propose a new routing protocol called multi-path routing (MPR) for VANETs. MPR is a beacon less routing protocol with carry-andforward mechanisms that forwards multiple copies from the packet and eliminates unneeded copies at the intersections. The proposed protocol creates enough diversity to reach the destination vehicle with shorter end-to-end delay. The paper shows via simulation that the proposed multi-path protocol is superior to other proposed protocols, especially in low vehicular density scenarios. The results show that MPR achieves shorter end-to-end delay and higher delivery ratio compared with the existing routing protocols for urban VANET communications.