IRS-enabled Breath Tracking with Colocated Commodity WiFi Transceivers

TL;DR

This paper demonstrates how IRS technology can significantly improve breath tracking accuracy using commodity WiFi devices by enhancing self-interference cancellation in indoor environments.

Contribution

It introduces an IRS-assisted method for self-interference cancellation in WiFi-based breath tracking, utilizing a 256-element IRS prototype to achieve room-level tracking accuracy.

Findings

Successful breath frequency detection in indoor environments

Effective IRS-assisted self-interference cancellation

Room-level breath tracking with commodity WiFi hardware

Abstract

Intelligent reflecting surfaces (IRS) are a key enabler of various new applications in 6G smart radio environments. By utilizing an IRS prototype system, this paper aims to enhance self-interference (SI) cancellation for breath tracking with commodity WiFi devices. SI suppression is a crucial requirement for breath tracking with a single antenna site as the SI severely limits the radio sensing range by shadowing the received signal with its own transmit signal. To this end, we propose to assist SI cancellation by exploiting an IRS to form a suitable cancellation signal in the analog domain. Building upon a 256-element IRS prototype, we present results of breath tracking with IRS-assisted SI cancellation from a practical testbed. We use inexpensive WiFi hardware to extract the Channel State Information (CSI) in the 5~GHz band and analyze the phase change between a colocated transmitter and receiver with added local oscillator (LO) synchronization. We are able to track the breath of a test person regardless of the position in an indoor environment in a room-level range. The presented case study shows promising performance in both capturing the breath frequency as well as the breathing patterns.