Characterization of FSO link performance considering weak to high turbulence conditions

Abstract Utilizing a line-of-sight link, free space optics (FSO) is a technology that employs a beam of light for the purpose of establishing an optical connection between two distant points, enabling the exchange of information. FSO communication through clear atmosphere suffers from challenges arising due to variations in refractive index of the air caused by random fluctuations in the atmospheric temperature. This results in a reduction of signal-to-noise ratio (SNR) of the received signal, subsequently impacting the overall performance of the link. The present study evaluates the outage probability, average capacity, and bit error rate (BER) performance of FSO communication system under turbulent environment utilizing binary phase shift keying (BPSK) as modulation technique. To evaluate the system’s error performance across varying turbulence levels, the probability density function (PDF) of the received irradiance, post-traversing the atmosphere has been represented through the Gamma–Gamma (G–G) model. Simulation results show that the BER improves from 10 −2 to 10 −4 with the increase in SNR from 5 dB to 20 dB under moderate turbulence conditions. Higher channel capacity up to 6.8 bits/s/Hz has been achieved, along with significant reduction in outage probability with an increased in the SNR values.