FSO System Optimization for 6G Applications: Using Metaheuristic Algorithms

This paper investigates the potential improvements in Free Space Optics (FSO) communication systems using Particle Swarm Optimization (PSO) and the Pachycondyla Apicalis Algorithm (API). FSO technology transmits data using laser beams, offering benefits like high bandwidth and enhanced security, with the capability to achieve data rates of up to 10 Gbps over distances of up to 2 km under favorable weather conditions. However, this technology faces challenges due to environmental factors such as rain, fog, and atmospheric turbulence, which can impact its performance. This study specifically addresses link margin degradation caused by these impairments and applies PSO as an efficient baseline metaheuristic, selected for its computational simplicity, rapid convergence, and robustness, while benchmarking its performance against the API algorithm. Simulation results indicate that PSO optimization significantly increases the link margin for various divergence angles compared to the API algorithm. For divergence angles of 1, 1.5, 2.4, and 3 mrad, the link margin improved by 6.4, 11.1, 9.8, and 7.6 dB, respectively, at a fixed transmitted power of 10 dBm. This demonstrates that PSO maintains a higher link margin at divergence angles above 2 mrad compared to both the API algorithm and the conventional scenario. The main contributions of this study are: the development of a bio-inspired optimization framework for FSO systems, enhancement of link robustness against turbulence, beam misalignment, and fading, and demonstration of the framework’s applicability to both current 5G backhaul scenarios and prospective 6G optical wireless networks. Beyond simulation, the framework has been verified for practical feasibility and shown to align with commercially available optical hardware. In addition, PSO can be integrated with real-time atmospheric sensing and predictive weather models to enable proactive parameter tuning, ensuring resilient and efficient 6G FSO deployment. Overall, the results confirm that misalignment-optimized PSO enhances resilience under severe conditions, supporting 6G availability requirements.