Modeling turbulence in underwater wireless optical communications based on Monte Carlo simulation

Abstract

Turbulence affects the performance of underwater wireless optical communications (UWOC). Although multiple scattering and absorption have been previously investigated by means of physical simulation models, still a physical simulation model is needed for UWOC with turbulence. In this paper, we propose a Monte Carlo simulation model for UWOC in turbulent oceanic clear water, which is far less computationally intensive than approaches based on computational fluid dynamics. The model is based on the variation of refractive index in a horizontal link. Results show that the proposed simulation model correctly reproduces lognormal probability density function of the received intensity for weak and moderate turbulence regimes. Results presented match well with experimental data reported for weak turbulence. Furthermore, scintillation index and turbulence-induced power loss versus link span are exhibited for different refractive index variations.

Experimental study of the turbulence effect on underwater optical wireless communications

“…5 compares the measured data with the lognormal distribution and the simulated results using the model in [22] for all states for a 12 m link span. ∆z and Ri are the width of consecutive turbulent layers and the radius of curved boundaries as defined in [22]. All the key system model parameters are shown in Table 2.…”

“…The refractive index variation Δn is one of the important factor influencing the turbulence strength as in the model reported in [22]. By adapting the model of [22] to the four turbulence states, Δn values are 1e-6, 4.4e-6, 7e-6 and 308e-6 for the states of 1, 2, 3 and 4, respectively. Note that, for the state 4 turbulence is due to both high T and Q, thus the highest Δn variation was observed.…”

“…Fig. 6 compares the measured and the simulated SI values as a function of the link span using the model in [22] for the states 1, 2 and 3. The SI values are obtained using the following equation: where I is the Vi /Vf .…”

“…Note that, in UOWC systems, the link span is one of the main factor influencing the received power fluctuations under turbulence conditions; however, to the best of our knowledge no research on the effects of turbulence over longer channel spans have been reported yet. Finally, we compare the measured results with generated data based on the model given in [22] and show that there is a good correlation between them. Fig.…”

The Channel Impulse Response of SIMO Underwater Optical Wireless Communication Link based on Monte Carlo Simulation

“…Note that, we have used the system model given in [11], where all considered noise sources are described in detail. In this work, we consider the link performance under weak turbulence, which is modelled as lognormal distribution [14], [15].…”