Remote Vital Sign Monitoring Based Millimeter-Wave Sensing

Abstract

Millimeter wave (mmWave) radar is an attractive solution for non-contact vital sign monitoring due to its characteristics of robustness against noise, interference, and high-range resolutions. However, due to the attenuation of mmWave signal strength with distance, most previous methods require users to be relatively close to the radar (<2.5m), and the estimation of vital signs is inaccurate due to the influence of surrounding objects. In this paper, we propose a vital sign remote monitoring method based on mmWave sensing, which can estimate the heart rate of multiple users at a long distance. We first propose an object location detection method based on windowing minimum variance distortionless response to enhance the signal SNR from weak human body reflections and obtain fine-grained each user’s location. Then we design a vital sign estimation method based on wavelet packet decomposition to extract precision vital signs from composite reflection signals. We evaluate the system performance and the impact of different factors, including the distance, angle, and multi-user scenario. Experimental results show that our method can achieve the heart rate accurately with a mean absolute error (MAE) of 3.5Bpm and mean absolute percentage error (MAPE) of 4% within 8m.