ROAR: A Multi-Rate Opportunistic AODV Routing Protocol for Ad-Hoc Networks

Springer-Verlag 5th International Conference on AD-HOC Networks and Wireless (ADHOC NOW'06), August 17-19th, Ottawa, Canada, 2006.

Past experimental works over ad-hoc test-beds have shown that constructing routes using hop-count lead to unreliable routes that have very low throughput. In this paper, we outline a simple approach, called ROAR, that exploits node diversity to increase the packet delivery ratio and throughput of routes constructed using either hop count or ETX. ROAR enables the ad-hoc on demand distance vector (AODV) routing protocol to strengthen its routes by recruiting neighbors of nodes on the least cost path as support nodes during the route construction process. Then, working closely with the medium access control (MAC) protocol and link-adaptation algorithm, ROAR employs an opportunistic forwarding scheme that takes advantage of the increased node diversity at each hop. We have implemented ROAR in the {\it ns-2} simulator over the IEEE 802.11a physical layer. From our simulation studies conducted using various network topologies and the Ricean radio propagation model, we find that ROAR increases the packet delivery ratio and end-to-end throughput by up to 300\%, especially hop count based routes. Therefore, ROAR provides a viable approach that retains the simplicity and benefits of using hop count in ad-hoc networks.
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