End-to-End Optical Propagation Modeling for Water-to-Air Channels under Sea Surface and UAV Effects

TL;DR

This paper presents a detailed Monte Carlo-based optical channel model for water-to-air communication, considering sea surface and UAV effects, to enable efficient underwater sensor data transmission.

Contribution

It introduces a comprehensive simulation framework that incorporates realistic sea surface, bubble scattering, and UAV instability effects for water-to-air optical links.

Findings

Achieves a bit-error rate of 10^-3 at 1 Mbps for 47 m depth and 13 m/s wind.

Demonstrates the practical feasibility of water-to-air optical communication under realistic conditions.

Analyzes the impact of wind, transmitter, and receiver parameters on channel performance.

Abstract

Underwater observatories have recently emerged as an efficient solution for marine biodiversity monitoring. The primary objective of this work is to enable efficient and cost-effective data muling from underwater sensors by investigating the use of optical wireless communications to transmit data from the underwater sensors to an aerial node close to the water surface, such as an unmanned aerial vehicle (UAV). More specifically, we utilize a direct water-to-air (W2A) optical communication link between the sensor node equipped with an LED emitter and the UAV equipped with an ultra-sensitive receiver, i.e., a silicon photo-multiplier. As a main contribution, we develop a comprehensive Monte Carlo-based ray-tracing algorithm to characterize this complex channel. This framework rigorously incorporates the impact of air bubbles modeled through the Mie scattering theory, a realistic sea surface representation derived from the JONSWAP spectrum, and an analytical derivation of the channel loss resulting from UAV instability under wind-induced perturbations. Furthermore, we conduct a comprehensive analysis of the W2A channel, examining the influence of key parameters such as wind speed, transmitter configurations, and receiver characteristics. The end-to-end performance evaluation demonstrates the practical feasibility of the proposed approach, achieving a bit-error rate of $10^{-3}$ at a data rate of 1 Mbps for a transmitter depth of 47 m and wind speeds up to 13 m/s.