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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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