Error Probability Analysis of IRS-Assisted Underwater Optical Wireless Communication Links

This paper investigates the error probability of intelligent reflecting surface (IRS)-assisted underwater optical wireless communication (UOWC) links in the presence of absorption, pointing errors, and optical turbulence. The underwater optical channel is modeled as a composite fading channel that jointly captures deterministic attenuation, turbulence-induced irradiance fluctuations, and beam misalignment effects. Optical turbulence is characterized using the modified Nikishov spectrum, while pointing errors are modeled through a Rayleigh-distributed displacement process. An intensity-modulated direct-detection (IM/DD) system employing on-off keying (OOK) is considered, and an integral-form expression for the average probability of error is derived by averaging the conditional error probability over the composite channel statistics. Numerical results demonstrate that IRS-assisted transmission significantly enhances link reliability, particularly for longer propagation distances and moderate signal-to-noise ratios. The results further indicate that increasing the number of IRS reflecting elements and improving reflection efficiency yield notable reductions in error probability, highlighting the effectiveness of IRS technology for improving the performance of underwater optical communication links in challenging propagation environments.