Outage Analysis for Relay-Aided Free-Space Optical Communications Over Turbulence Channels With Nonzero Boresight Pointing Errors

Free-space optical (FSO) communications has recently received significant attention and commercial interest for a variety of applications. In this paper, the outage probabilities for both the parallel and serial relay-aided FSO communications are analyzed. Initially, a new aggregated channel fading model is established, which considers atmospheric attenuation, M-distributed atmospheric turbulence, and nonzero boresight pointing errors. After that, the statistical characteristic of the aggregated channel is analyzed. Under the aggregated channel model, closed-form expressions of the outage probabilities for both the parallel and serial relay-aided FSO communications are derived, respectively. Numerical results show that the derived theoretical expressions are quite accurate and can provide sufficient precision for evaluating the outage performance, which is helpful to the design of future FSO communication systems.