Comments on “Performance Analysis of Coherent Free-Space Optical Systems With Multiple Receivers”

In this letter, we point out that a much simpler ergodic capacity formula for a coherent free-space optical system employing multiple receive apertures over atmospheric turbulence-induced fading channels could be derived, in a more useful and elegant approach to Meijer's G-function, than the one provided in the above letter. Furthermore, we also derive a concise asymptotic ergodic capacity expression, which offers more explicit insights into the impact of system and channel parameters on the ergodic capacity in the high signal-to-noise ratio regime.