Monte-Carlo-Based Channel Characterization for Underwater Optical Communication Systems

TLDR

Underwater wireless optical communication systems require channel characterization because photon absorption and scattering in water affect signal propagation. The study aims to quantify channel time dispersion across different water types, link distances, and transceiver characteristics using realistic parameters. Monte Carlo simulations of photon trajectories with a two‑term Henyey–Greenstein scattering model were used to evaluate bit‑error‑rate performance with on‑off‑keying modulation. The two‑term model outperforms the standard Henyey–Greenstein model, and numerical results show that time dispersion—and thus inter‑symbol interference—is negligible at moderate distances except in highly turbid waters, providing design guidance for UWOC systems.

Abstract

We consider channel characterization for underwater wireless optical communication (UWOC) systems. We focus on the channel impulse response and, in particular, quantify the channel time dispersion for different water types, link distances, and transmitter/receiver characteristics, taking into account realistic parameters. We use the Monte Carlo approach to simulate the trajectories of emitted photons propagating in water from the transmitter towards the receiver. During their propagation, photons are absorbed or scattered as a result of their interaction with different particles present in water. To model angle scattering, we use the two-term Henyey–Greenstein model in our channel simulator. We show that this model is more accurate than the commonly used Henyey–Greenstein model, especially in pure sea waters. Through the numerical results that we present, we show that, except for highly turbid waters, the channel time dispersion can be neglected when working over moderate distances. In other words, under such conditions, we do not suffer from any inter-symbol interference in the received signal. Lastly, we study the performance of a typical UWOC system in terms of bit-error-rate using the simple on–off-keying modulation. The presented results give insight into the design of UWOC systems.