Performance Improvements Provided by Route Diversity in Multihop Wireless Networks

In multihop wireless networks, the variability of channels results in some paths providing better performance than other paths. Although it is well known that some paths are better than others, a significant number of routing protocols do not focus on utilizing optimal paths. However, cooperative diversity, which is an area of recent interest, provides techniques for efficiently exploiting path and channel diversity. This paper examines the potential performance improvements offered by path diversity. Three settings are examined, namely, where the path loss and channel correlation are neglected, where path loss is considered, but channel correlation is neglected, and where path loss and channel correlation are both accounted for. It is shown that, by exploiting path diversity, dramatic improvements in the considered route metric may be achieved. Furthermore, in some settings, if the link statistics are held constant, then when path diversity is exploited, the route metric improves with path length. This implies that, if links statistics are fixed and if sufficient path diversity exists, then paths with more hops tend to support higher bit rates than paths with fewer hops. It is shown that such behavior occurs when a particular map has a nonzero fixed point.