Underwater Messaging Using Mobile Devices

TL;DR

This paper introduces a novel software-based underwater messaging system that utilizes existing mobile device microphones and speakers, enabling real-time acoustic communication in underwater environments without specialized hardware.

Contribution

It presents the first acoustic underwater messaging system compatible with standard mobile devices, adapting to environmental changes and demonstrating practical real-world performance.

Findings

Achieves bit rates of 100 bps to 1.8 kbps at 30 m range

Can extend range to 100 m at lower bit rates

Successfully operates in diverse real-world underwater environments

Abstract

Since its inception, underwater digital acoustic communication has required custom hardware that neither has the economies of scale nor is pervasive. We present the first acoustic system that brings underwater messaging capabilities to existing mobile devices like smartphones and smart watches. Our software-only solution leverages audio sensors, i.e., microphones and speakers, ubiquitous in today's devices to enable acoustic underwater communication between mobile devices. To achieve this, we design a communication system that in real-time adapts to differences in frequency responses across mobile devices, changes in multipath and noise levels at different locations and dynamic channel changes due to mobility. We evaluate our system in six different real-world underwater environments with depths of 2-15 m in the presence of boats, ships and people fishing and kayaking. Our results show that our system can in real-time adapt its frequency band and achieve bit rates of 100 bps to 1.8 kbps and a range of 30 m. By using a lower bit rate of 10-20 bps, we can further increase the range to 100 m. As smartphones and watches are increasingly being used in underwater scenarios, our software-based approach has the potential to make underwater messaging capabilities widely available to anyone with a mobile device. Project page with open-source code and data can be found here: https://underwatermessaging.cs.washington.edu/