Performance evaluation of modulating retro-reflector underwater wireless optical communication links in oceanic turbulence

Although Modulating retro-reflector (MRR) technology offers a promising low-power solution for underwater wireless optical communication (UWOC), its performance under challenging oceanic turbulence has not been comprehensively analyzed. This paper addresses this gap by developing a robust model for an MRR-UWOC system operating through a turbulent channel. This paper derives the joint probability density function (PDF) for the turbulence-induced fading of the MRR-UWOC link based on the Exponentiated Weibull (EW) distribution and the generalized oceanic turbulence optical power spectrum (OTOPS) model. Utilizing this PDF, we obtain an approximate analytical expression for the average bit error rate (BER) of an on-off keying (OOK) system using the Gauss-Hermite quadrature method. Analysis of the turbulence confirms that aperture averaging mitigates fading and reveals a supersaturation effect. This analysis also indicates that the system is more sensitive to temperature variations than to salinity fluctuations. Furthermore, a comprehensive MRR UWOC model incorporating path loss from absorption and scattering reveals that these factors play fundamentally different roles: turbulence establishes a theoretical performance floor, while path loss imposes a power penalty on this baseline. The established model offers valuable guidance for the practical design and optimization of underwater optical networks.