Short-Range Vital Signs Sensing Based on EEMD and CWT Using IR-UWB Radar

The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities, and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. No conventional Doppler only can capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantages of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications. Compared with traditional contact measurement devices, experimental results utilizing a 2.3 GHz bandwidth transceiver, demonstrate 100% similar results.