Outage performance analysis of mth best path selection protocol in FSO communications

In this paper, we investigate the performance of free space optical (FSO) systems with parallel multihop relaying and path selection. Specifically, we consider an FSO communication system which employs M parallel relaying paths each of which consists of N decode-and-forward relays. We assume the deployment of the so-called m^th best path selection (m-BPS) protocol. In this protocol, data is transmitted through the m^th (m≥2) best path towards the destination since the best path (i.e., m = 1) might not be available due to scheduling or load balancing issues. Under the assumption of log-normal turbulence channels, we derive a closed form outage probability expression for the FSO communication system with m-BPS protocol and further confirm the accuracy of derived expression through Monte Carlo simulations.