Diversity–Multiplexing Trade-Off in Coherent Free-Space Optical Systems With Multiple Receivers

In this paper, from an information theory point of view, we investigate the performance of a coherent free-space optical (FSO) communication system with multiple receive apertures over atmospheric turbulence channels. Our study builds on a recently introduced statistical model that characterizes the combined effects of turbulence-induced wavefront distortion and amplitude fluctuation in coherent receivers with phase compensation. We investigate the link reliability as quantified by “diversity gain” and the relationship between the link reliability and the spectral efficiency as quantified by “diversity-multiplexing trade-off (DMT).” Our results provide insight into the performance mechanisms of coherent FSO systems and demonstrate significant performance gains that can be obtained through the deployment of multiple receive apertures and phase compensation techniques.