Ergodic Capacity Optimization of FSO Systems over Gamma-Gamma Atmospheric Turbulence Channels with Generalized Pointing Errors

摘要

A novel approximate closed-form expression for the ergodic capacity of free-space optical (FSO) communication links over gamma-gamma (GG) atmospheric turbulence channels with generalized pointing errors is presented. The obtained expression is entirely valid from low to high signal-to-noise-ratio (SNR). It is concluded that despite generalized pointing errors cannot be ignored in capacity performance; they can be considerably mitigated by selecting an optimum beam width at the transmitter-side. In other words, there is an optimum normalized beam width value that minimizes the effect of pointing errors on capacity performance at high SNR that does not depend on atmospheric turbulence.