Diversity of multi-hop cluster-based routing with arbitrary relay selection

Clustered multi-hop wireless networks have attracted significant attention for their robustness to fading, hierarchical structure, and ability to exploit the broadcast nature of the wireless channel. The authors propose an opportunistic routing (or relay selection) algorithm for such networks. In contrast to the majority of existing approaches to routing in clustered networks, the algorithm presented in this study only requires channel state information in the final hop, which is shown to be crucial for reaping the diversity offered by the channel. In addition to exploiting the available diversity, our simple cross-layer algorithm has the flexibility to simultaneously satisfy an additional routing objective such as the maximisation of network lifetime. The authors demonstrate through analysis and simulation that our proposed routing algorithm attains full diversity under certain conditions on the cluster sizes, and its diversity is equal to the diversity of more complicated approaches that require full channel state information.