Using Channel State Information for Tracking Vital Signs of a Patient

Tracking vital signs such as respiration rate and heart rate during sleep enable the practitioners to diagnose various diseases. The sensor-embedded wearable devices have the ability to track these vital signs. However, they require the patients to wear/carry such devices all the time. These devices have limitations imposed on their battery lifetime, charging mechanism and hardware-related cost. Moreover, the data transmitted by these devices may be inaccurate at times. To track these vital signs during sleep, with minimal hardware-related cost, we use channel state information (CSI) to capture even the minute fluctuations in a WiFi signal. The CSI measurements are observed for fluctuations in the amplitude and frequency over all the subcarriers of a 20MHz IEEE 802:11 a/g/n channel. The measurements of these parameters vary with minute movements caused by heartbeats and respiration rate. Various type of filters are used to filter out any noise, unlikely caused by heartbeats and respiration rate. Our proposed scheme is equally applicable to both stationary and moveable positions of a patient, while
asleep.