Vimo: Vital Sign Monitoring Using Commodity Millimeter Wave Radio

Accurate monitoring of human vital signs (e.g. breathing and heart rates) is crucial in detecting medical problems. In this paper, we propose ViMo, a calibration-free remote Vital sign Monitoring system that can simultaneously monitor multiple users by leveraging the channel impulse response (CIR) of 60GHz WiFi. By exploiting the periodicity introduced by respiration, we first propose a human detection algorithm which does not require any prior calibration. Then, we apply the auto-correlation function (ACF) of the CIR phase to estimate the breathing rate. Lastly, to mitigate the impact of the breathing signal on the weak heartbeat signal, the cubic spline interpolation is used to eliminate the breathing signal before the estimation of the heart rate. Extensive experiments show that ViMo can achieve a median accuracy of 0.19 BPM for breathing rate estimation and 1 BPM for heart rate estimation, outperforming the existing non-contact solutions that are purely based on frequency analysis.