Towards Low-Cost and Resource-Efficient IEEE 802.15.4Z-Compliant Ultra-Wideband Breathing Rate Estimation

This work explores a cost-effective, compact, and resource-efficient Impulse-Radio Ultra-Wideband (IR-UWB) radar solution for breathing rate (BR) estimation, leveraging IEEE 802.15.4z-compliant hardware. We discuss antenna requirements for compact radar systems, propose Cavity-Backed Slot (CBS) antennas in Air-Filled Substrate-Integrated-Waveguide (AFSIW) technology as ideal candidates, and propose a solution to further enhance signal integrity in arrays through mutual coupling reduction and system-level optimization in the time domain. Measurements for BR estimation using Qorvo's DWM3000 commercial off-the-shelf (COTS) transceivers and a Convolutional Neural Network (CNN)-based implementation are also demonstrated. Results from tests with 16 participants in three realistic scenarios show accurate performance, with the CNN achieving robust BR estimation even in complex setups. This study highlights the potential of radar-based BR estimation on existing, cost-effective IR-UWB systems, paving the way for Integrated Sensing and Communication.