Average capacity for heterodyne FSO communication systems over gamma-gamma turbulence channels with pointing errors

A closed-form expression for the average capacity of the heterodyne differential phase shift keying (DPSK) free-space optical (FSO) communication systems over gamma-gamma turbulence channels is derived by considering the effect of pointing errors. Numerical results show the average capacity can be evaluated with the effect of atmospheric turbulence conditions, beamwidth and jitter variance. Meanwhile, these results verify the accuracy of our mathematical analysis. This work can be helpful for the heterodyne DPSK FSO communication system designer.