Breathfinding: A Wireless Network that Monitors and Locates Breathing in a Home

TL;DR

This paper presents a wireless network-based system that accurately estimates breathing rate and location of a person in a home environment, even amidst motion interference, with potential applications in healthcare and security.

Contribution

Develops a novel method to estimate breathing rate and locate a person using RSS measurements despite motion interference, without calibration.

Findings

Accurately estimates breathing rate during various activities.

Locates breathing person within about 2 meters in a home setting.

Performs reliably in short and long-duration tests.

Abstract

This paper explores using RSS measurements on many links in a wireless network to estimate the breathing rate of a person, and the location where the breathing is occurring, in a home, while the person is sitting, laying down, standing, or sleeping. The main challenge in breathing rate estimation is that "motion interference", i.e., movements other than a person's breathing, generally cause larger changes in RSS than inhalation and exhalation. We develop a method to estimate breathing rate despite motion interference, and demonstrate its performance during multiple short (3-7 minute) tests and during a longer 66 minute test. Further, for the same experiments, we show the location of the breathing person can be estimated, to within about 2 m average error in a 56 square meter apartment. Being able to locate a breathing person who is not otherwise moving, without calibration, is important for applications in search and rescue, health care, and security.