Link quality improvement analysis of relay-assisted hybrid RF/FSO systems in challenging environments

Hybrid RF/FSO systems have gained significant attention recently as a reliable approach to enhancing wireless data transmission rates. Intelligent selection between RF and FSO links, driven by the switching mechanism and diversity, plays a pivotal role in ascertaining the quality of the connection. This process, hinged upon a predefined threshold, significantly influences link quality determination. However, conventional methods for determining the switching rely on extensive numerical simulation leading to abrupt switching. To address this issue, this paper introduces an innovative relay-assisted multi-link hybrid switching mechanism that combines RF/FSO technologies. Notably, the proposed mechanism integrates a link-quality aware strategy to attain an optimal threshold level, thereby addressing the aforementioned problem effectively. The proposed mechanism utilizes an evolutionary seagull-based link quality-aware switching scheme to minimize bit error rates while maximizing capacity, considering the outage probability of both RF and FSO systems. The proposed methodology enhances the overall quality of links by introducing an intermediate decode-and-forward relay and multiple connections. Several criteria, including as outage probability, bit error rate, and ergodic capacity, are used to evaluate this improvement. A comparative analysis is conducted to evaluate the performance of the proposed approach in contrast to existing FSO systems. The findings highlight the promising capabilities of the relay-assisted hybrid RF/FSO system, showcasing its ability to significantly improve the quality of connections. This research contributes to advancing hybrid RF/FSO systems and their applicability in scenarios where atmospheric conditions, pointing errors, and fading effects influence link quality. •Nakagami-m and Malaga distributions characterize RF and FSO channels while accounting for key transmission losses, including turbulence, misalignment errors, and fading.•Developed closed-form expressions for BER, outage probability, and channel capacity to analyze relay-assisted hybrid RF/FSO systems under turbulence, pointing errors, and RF fading.•Proposed an efficient multi-objective evolutionary-based switching scheme to optimize threshold values while considering BER and capacity trade-offs.•Improved relay protocol by conditioning data transfer on relay node.