Bit error rate performance analysis of an underwater wireless optical communication system based on an aggregate...

Underwater wireless optical communication (UWOC) has broad application prospects in fields such as ocean observation and underwater detection due to its advantages of high bandwidth and low latency. However, signal attenuation caused by absorption and scattering, pointing errors, and turbulence in underwater channels severely affect system reliability. Therefore, accurate modeling of channel characteristics and analysis of bit error rate (BER) performance are key problems in system design. In this paper, an aggregate channel model is proposed for UWOC systems. It comprehensively considers absorption-scattering attenuation and pointing errors. In addition, the hybrid exponential-generalized gamma (EGG) distribution model is adopted to characterize turbulence-induced signal fluctuations. The cumulative distribution function of the aggregate channel transmittance and the closed-form expression for the system's average BER under OOK modulation are derived. Furthermore, a simple closed-form approximation of the average BER for the UWOC is further derived in the high signal-to-noise ratio (SNR) regime. Then a Monte Carlo (MC) simulation platform is established for verification. The results show that the theoretical curve is highly consistent with the MC simulation data points. The attenuation coefficient of water quality determines the maximum reachable distance of the system, and the increase of turbulence intensity will systematically raise the BER curve. This degradation requires additional SNR margin for compensation. The results show that with the increase of transmission distance, the BER performance deteriorates. However, the performance can be improved by increasing the SNR, the transmission power, and the receiving aperture or reducing the beam divergence angle. The proposed model is appropriate for the assessment and optimization of UWOC systems.