Work on Air-Water Laser Link Won NSDI Best Paper Award

Air-water communication is fundamental for efficient underwater operations, such as environmental monitoring, surveying, or coordinating of heterogeneous aerial and underwater systems. Existing wireless techniques mostly focus on a single physical medium and fall short in achieving high-bandwidth bidirectional communication across the air-water interface.

A project from the DartNets and RLab at Computer Science Department and a research group at Thayer engineering school designed a bidirectional, direct air-water wireless communication link based on laser light. While air-water laser communication has been studied in the past, prior works commonly assume a controlled lab setting with calm water, with many practical challenges left unsolved. The proposed system, referred to as AmphiLight, overcomes these practical challenges including water dynamics, mobile laser steering, and strong ambient light interference.

Specifically, AmphiLight adapts to water dynamics with ultrasonic sensing, steers within a full 3D hemisphere using only a MEMS mirror and passive optical elements, and mitigate ambient light interference by exploiting the spectral sparsity of laser light. In real-world experiments, AmphiLight achieves static throughputs up to 5.04 megabits per second, zero bit-error transmission ranges up to 6.1 m in strong ambient light conditions, and connection time improvements between 47.1% and 29.5% during wave dynamics.

The team published the results in the 17th USENIX Symposium on Networked Systems Design and Implementation (NSDI), a top conference in systems and networking and the paper is one of the two papers awarded the best paper in the conference.

Please find the paper, slides, and presentation video at the NSID'20 website.