End-to-end performance of mixed RF/FSO transmission systems

In this paper, we consider a heterogenous scenario where free-space optical (FSO) and radio-frequency (RF) technologies are deployed together as a dual-hop communication system, and we investigate the end-to-end outage performance of this so-called mixed RF/FSO system. The RF and FSO links are, respectively, modeled as Rayleigh fading (due to multipath propagation) and M-distributed fading (due to atmospheric turbulence). We derive exact closed-form expressions for the outage probability and demonstrate that the existing outage results in the literature for mixed FSO systems can be obtained as special cases of our results. The effect of pointing errors in the FSO link is further investigated.