Software-Defined Visible Light Networking for Bi-Directional Wireless Communication Across the Air-Water Interface

Autonomous networks of sensors, unmanned aerial vehicles (UAVs) and unmanned underwater vehicles (UUVs) will play a vital role in scenarios/applications where a plethora of distributed assets across multiple domains - air and water - operate in unison to accomplish a common goal. However, establishing high data rate, robust, and bi-directional communication links across the air-water interface between aerial and underwater assets is still an open problem. In this article, we propose a communication system based on visible (blue) light that enables aerial and underwater assets to establish bi-directional links through the air-water interface without requiring any preexisting communication infrastructure such as buoys acting as relay nodes. We first derive a mathematical model and accordingly build a simulator for the bi-directional air-water visible light communication (VLC) channel accounting for water surface distribution, optical parameters and path losses. Then, we design and prototype a software-defined visible light communication (VLC) modem. We present an extensive experimental evaluation conducted both in a test tank and in the ocean using the proposed VLC modem prototypes.