Evaluation of Underwater Optical Wireless Channels over F Turbulence for Different Detection Types

This paper presents a comprehensive performance study for the underwater optical wireless communication (UOWCs) channel, accounting for the effects of attenuation, turbulence, pointing errors, and fluctuations in the angle-of-arrival (AOA), modeled by the Beer-Lambert model, the Fisher-Snedecor F turbulence, Hoyt, and Rayleigh distributions, respectively. Considering the stochastic nature of UOWC, closed-form expressions for outage probability, average bit-error-rate (BER), and ergodic capacity are derived. The results revealed that increasing the field-of-view (FoV) reduces the impact of aoa fluctuations. Asymmetric two-dimensional beam misalignment exhibits better outage probability performance compared to symmetric misalignment. Furthermore, heterodyne detection consistently outperforms direct detection. When employing heterodyne detection, M-quadrature amplitude modulation (M-QAM) achieves superior BER performance. Additionally, as absorption increases with longer wavelengths, BER performance deteriorates. Narrower beamwidths improve ergodic capacity by enhancing received signal power.