Performance analysis of free-space optical communication systems over atmospheric turbulence channels

TLDR

Turbulence fading is a primary impairment in free‑space optical communication, and log‑normal and gamma–gamma models accurately capture this atmospheric turbulence. The authors aim to evaluate the performance of free‑space optical systems over log‑normal and gamma–gamma turbulence channels. They derive closed‑form expressions for average capacity and outage probability for both models and analyze how link length and receiver aperture affect these metrics. The analytical results are confirmed by numerical examples and can replace time‑consuming Monte‑Carlo simulations.

Abstract

Turbulence fading is one of the main impairments affecting the operation of free-space optical (FSO) communication systems. The authors study the performance of FSO communication systems, also known as wireless optical communication systems, over log-normal and gamma–gamma atmospheric turbulence-induced fading channels. These fading models describe the atmospheric turbulence because of its very good agreement with experimental measurement data. Closed-form expressions for the average (ergodic) capacity and the outage probability are derived for both statistical models. Another contribution of this work is a study of how the performance metrics are affected by the atmospheric conditions and other parameters such as the length of the link and the receiver's aperture diameter. The derived analytical expressions are verified by various numerical examples and can be used as an alternative to time-consuming Monte-Carlo simulations.