Performance analysis of underwater wireless optical communication under egg turbulence and link orientation

Underwater Wireless Optical Communication (UWOC) is a promising technology for high-data-rate underwater communication due to its high bandwidth and low latency, with potential applications in Internet of Underwater Things (IoUT) systems. However, UWOC performance is significantly affected by underwater channel impairments such as turbulence, optical attenuation, and transmitter–receiver pointing errors. In this work, a comprehensive physical-layer performance analysis of UWOC systems is presented by considering Exponential Generalized Gamma (EGG) turbulence and different link orientations. Horizontal, vertical, and diagonal link configurations are investigated to characterize the influence of link orientation and depth-dependent turbulence on system performance. The EGG distribution is employed to model underwater turbulence over weak-to-strong turbulence regimes, while optical attenuation and pointing errors are incorporated into the channel model. Closed-form analytical expressions for average bit error rate (BER), outage probability (OP), and channel capacity (CC) are derived for the considered link configurations. For vertical and diagonal links, the underwater propagation path is modeled using multiple non-mixing layers with layer-dependent turbulence characteristics. The analytical results are validated through Monte Carlo simulations, showing good agreement between the analytical and simulation results. The obtained results demonstrate the effects of link orientation, depth-dependent turbulence, attenuation, and pointing errors on UWOC system performance, providing useful insights for the design of reliable underwater optical communication links for potential IoUT applications.