Evaluation of Free Space Optical (FSO) Link Under Weather Conditions in Abidjan

Free Space Optical (FSO) communication systems use laser beams to transmit data through the atmosphere. No physical transmission media is required and it is a good response to the growing demands in terms of communication broadband. Taking into account the specific atmospheric conditions of Abidjan, this study evaluates the performance of the FSO link. Abidjan is a subtropical region where climatic variations significantly influence the propagation of optical signals, leading to phenomena such as diffusion, pointing errors, and link blockage. The atmospheric characteristics are presented and the effects of various climatic factors and seasonal changes on laser beam propagation are assessed. Results reveal that the rainy season is the least favorable period for the deployment of FSO links, with rain being the primary attenuation factor, causing a signal reduction measured at 2.5 dB/km during the month of June. To deepen our understanding of system performance, the Bit Error Rate (BER) was assessed under these specific conditions. For this purpose, several turbulence models were studied to identify which best represents the dynamics of turbulence in this environment. Through numerical simulations, the efficiency of four main models (Málaga, Gamma-Gamma, Lognormal, and K-Distribution) was systematically evaluated by comparing their predictions with the results of Monte Carlo simulations. The study demonstrates that the Málaga model provides the most accurate results, with a Mean Squared Error (MSE) of 0.009398 and a Mean Absolute Error (MAE) of 0.018925 in estimating the turbulence distribution and system performance, highlighting its robustness and applicability in complex environments. Finally, the observed BER values, on the order of 10 -6 , indicate that deploying FSO links in Abidjan is feasible, despite the challenges posed by seasonal rains, suggesting promising potential for the development of FSO systems by implementing appropriate mitigation strategies to optimize performance under changing weather conditions.