BER analysis of improved path selection criterion for cluster-based multi-hop cooperative networks

In this paper, we study path selection criteria in cluster-based multi-hop cooperative networks with decode-and-forward relays over Rayleigh fading channels. The hop-by-hop path selection criterion, in which routing is done based on local channel state information, loses diversity gain due to lack of relay selection in the last hop. To overcome this issue, we study an improved path selection strategy, in which final two hops are selected jointly to achieve the maximum spatial diversity. The exact and asymptotic expressions of bit-error-rate are derived for both the path selection schemes. Numerical results show that the improved path-selection criterion performs far better than that of hop-by-hop selection criterion with a little increase in implementation complexity.