Performance enhancement of relay-assisted optical wireless links using weighted mean parameter optimization under various atmospheric impairments

Abstract

Free space optical (FSO) communication offers high-capacity, secure, and cost-effective transmission, but its performance degrades severely under atmospheric impairments such as fog, pointing errors, turbulence, and angle of arrival (AoA) fluctuations. This paper proposes a relay-assisted FSO communication framework employing an amplify and forward (AF) protocol and an integrated alternating and weighted mean of vectors Optimization (IA-WMoV) to enhance link reliability. Unlike prior studies that optimize signal parameters, the proposed approach jointly optimizes beam width, Field of View (FoV), and relay node placement under a unified composite channel model that captures attenuation loss, turbulence, pointing error, and AoA variations. The main contribution of this work is present in the formulation of a realistic multi-impairment channel model, the development of a multi-parameter IA-WMoV optimization scheme, and performance benchmarking under varied atmospheric scenarios (sunny, thin foggy, moderate foggy). Moreover, for sunny, thin foggy, and moderate foggy conditions, the average Bit error rate (BER) is 3.51E−06, 1.11E−04, and 1.11E-−03 with an optical power of 4 dB, outperforming existing heuristic and evolutionary optimization approaches. The results confirm that the proposed optimization framework significantly reduces outage probability and enhances system resilience, making it suitable for practical deployments such as UAV-based relays, disaster management, and next-generation high capacity wireless networks.