Modeling and Analysis of Underwater Wireless Optical Propagation Channels in SIMO-EGG Systems With Arbitrary Receiver Array Geometries

We introduce a piecewise Gaussian beam spread function with $ N $ segments ( $\text {PG-BSF}_{N}$ ) to characterize the optical propagation channels in single-input multiple-output (SIMO) underwater wireless optical communication (UWOC) systems, with a particular focus on scenarios involving receiver array of various geometries. This model employs a piecewise Gaussian function to flexibly describe the spatial relationship between the optical beam and receiver array of various geometries. It is highly effective in capturing the spatial differences among the receiver array and their impact on system performance when receivers are independent and nonidentically distributed. Comparisons with Monte Carlo (MC) simulations demonstrate that the $\text {PG-BSF}_{N}$ model achieves high consistency in predicting system performance, such as outage probability (OP) and average bit error rate (ABER), across different water qualities, receiver jitter levels, and configurations of independent nonidentically distributed receivers, thereby verifying its robustness and accuracy under complex conditions. In terms of OP, the $\text {PG-BSF}_{N}$ model significantly outperforms the traditional Beer-Lambert (BL) model, with differences reaching tens of dB under severe receiver jitter. These findings are crucial for the efficient and precise design of physical and network layer algorithms for the underwater Internet of Things (UIoT).