Affordable Non-Contact Respiration Monitoring Using Wi-Fi CSI and Doppler Radar: A Performance-Cost Trade-Off for Resource-Limited Settings
Non-contact vital sign monitoring has gained significant attention for enabling continuous in-home health surveillance without user discomfort or privacy intrusion. This study compares the performance and economic feasibility of two promising technologies - Wi-Fi Channel State Information (CSI) and Doppler radar phase measurement - for non-contact respiration monitoring. We developed and evaluated a system integrating a commodity 2.4 GHz Wi-Fi module and a 24 GHz continuous-wave (CW) Doppler radar, collecting respiration data from ten participants. The systems achieved a mean breathing rate accuracy of 92.01% (Wi-Fi) and 93.95% (radar), validated against a medical-grade chest belt. A cost-performance analysis indicates that Wi-Fi sensing offers a highly cost-effective solution, providing comparable accuracy to radar at a fraction of the hardware cost, making it suitable for scalable deployment in low-income regions, such as Bangladesh.
