Outage performance of multi-hop hybrid FSO/RF communication systems

In this paper, five scenarios are considered for the realization of a multi-hop hybrid free-space optical/radio frequency (FSO/RF) communication system with decode-and-forward (DF) relaying, and analytical outage probability expressions are derived. The scenarios have a different number of FSO and RF links. The aim is to identify an optimum scenario to effectively improve the end-to-end reliability of the multi-hop hybrid FSO/RF system. Outage performance is investigated for the scenarios under various weather conditions through numerical examples. It is identified that for a given link distance the end-to-end outage probability is minimized when using a hybrid FSO/RF link between every two successive nodes of the multi-hop system, and this requires the maximum number of FSO and RF links to be deployed.