Design of A Robust Noncontact Vital Signs (NCVS) Monitoring System Using Software defined radio (SDR)

A Feasibility Study of Remote Non-Contact Vital Signs (NCVS) Monitoring in a Clinic Using a Novel Sensor Realized by Software-Defined Radio (SDR)

“…angle that the receive (RX) antenna can receive the reflected transmit (TX) signal from the monitored subject, and that there is sufficient distance separating the TX/RX antennas to reduce their interactions. The fundamental operational principle of our Doppler-based NCVS system has been described in [4][5][6][7] and above. Basically, our system transmits a 2.4 GHz continuous wave (CW) RF signal and then receives the reflected wave off the subject's chest wall.…”

“…can all be changed in this GUI. The fundamental operational principle of our Doppler-based NCVS system has been described in [4][5][6][7] and above. Basically, our system transmits a 2.4 GHz continuous wave (CW) RF signal and then receives the reflected wave off the subject's chest wall.…”

“…New variants of the virus, such as the delta variant, delta plus variant, lambda variant, omicron variant, etc., continue to pop up. To help protect healthcare workers (HCWs), remote monitoring of vital signs using various techniques such as visible light sensing [1], millimeter wave radar [2], UWB (ultra-wideband) radar sensor [3], phased-array and fixed beam CW (continuous-wave) radar sensors using custom hardware [4,5], and software-defined radio (SDR)-based radar sensor systems have all been reported [6][7][8][9][10][11]. Differently from traditional contact-based vital signs monitoring systems currently widely used in clinically practices, these remote or non-contact vital signs (NCVS) monitoring systems are targeted to monitor patients' vital signs remotely and continuously; therefore, if an NCVS sensor system can be proven to be robust enough for clinically use, it would offer some key advantages as follows: (1) the HCWs can avoid direct contact with people infected with COVID-19 during vital signs setup/adjustment/reading to reduce their infection risks; (2) the NCVS monitoring system can be used on people suspected to be or confirmed infected with COVID-19 to safely quarantine them at home or in a hotel for telemedicine practice and for wireless acute-care.…”

“…The UWB radar [3], on the other hand, directly measures the periodic distance change in chest movement to estimate the RR and HR. As for the SDR-based radar sensor systems, several studies have focused on the phase changing of the received signals [6][7][8][9], while one work also targeted the distance variation [10], and the other extracted the RR and HR by analyzing the change in both phase and magnitude of the received signal [11].…”

“…Using a robust universal SDR box hardware with a mature software development environment (i.e., LabView) provides some significant advantages to speed up prototype development and potential future clinical deployment, as well as offering good system reliability and easy functionalities updates. Our initial NCVS system utilized a homodyne receiver architecture [7], and then further improvement to the system's robustness is achieved by using a low-IF (intermediate frequency) receiver architecture with excellent RR and HR monitoring accuracy and optimized gain settings [8]. The Low-IF NCVS system is currently being used in a clinical trial at TTUHSC to further test the system's accuracy and limitations, as the results will be reported in this paper.…”