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

Monte-Carlo-Based Impulse Response Modeling for Underwater Wireless Optical Communication

“…We consider a λ = 532 nm source with maximum initial divergence angle θ 0 = 10 • and a photon receiver with 50 cm aperture [10]. The double Gamma function is adopted to fit the channel impulse response obtained from the Monte Carlo simulations.…”

SIMO detection schemes for underwater optical wireless communication under turbulence

“…The Monte Carlo (MC) raytracing method is an effective way to obtain the channel properties, such as path loss and impulse response [21,22]. For the scattering/absorption channel, the channel characteristics are largely determined by the optical properties of water and by the system parameters of the UOWC links, such as the beam divergent angle, communication range, and field of view (FOV) of the receiver.…”

“…In this paper, we will use the MC ray-tracing method and largely follow the simulation procedures of Refs. [21,22] to evaluate the path loss performance, namely, P l in Eq. (1), of the UOWC channel.…”

“…The simulation system parameters are given in Table 1, and clear ocean water with the optical properties given in Ref. [22] is considered. Under this condition, the scattering by suspended particles is not so significant and UOT is the dominant factor in the channel.…”

375-nm ultraviolet-laser based non-line-of-sight underwater optical communication

“…It is affected not only by the channel geometries but also the water turbidity, transmission power, and wavelength utilized in the data transmission channel. It is noted that in the literature merely reports on simulation works, for instance those based on Monte Carlo method [19] and Henyey-Greenstein (HG) phase function [3], including impulse response [17,20], bit-error rate (BER) performance predictions [17,21] as well as the effect of channel geometries on path loss [22]. Experimental data is much needed to guide the experimental design of eventual long-distance NLOS transmission.…”