Radio Frequency Based Heart Rate Variability Monitoring

Heart rate variability (HRV), which measures the fluctuation of heartbeat intervals, has been considered as an important indicator for general health evaluation. In this paper, we present mmHRV, a contact-free HRV monitoring system using commercial millimeter-wave (mmWave) radio. We devise a heartbeat signal extractor, which can optimize the decomposition of the phase of the channel information modulated by the chest movement, and thus estimate the heartbeat signal. The exact time of heartbeats is estimated by finding the peak location of the heartbeat signal while the inter-beat intervals (IBIs) can be further derived for evaluating the HRV metrics. Experimental results show that mmHRV can measure the HRV accurately with 3.68ms average error of mean IBI (w.r.t. 99.49% accuracy) based on the experiments over 10 participants.