Wireless Vital Signs Detection System
Abstract
1. How can we bridge the Vital Sign (Breathing Rate) with the wireless signal?
- Human breathing will cause the movement of chest (or abdomen/belly) ranging from 4-12mm (PDF) with frequency of 6-30 breaths per minute (BPM). Moreover, the chest movement will induce corresponding CSI changes, which can then be measured by WiFi Links. As a result, we can extract the chest movement (a.k.a. Breathing Rate) from the measured CSI.
2. Can CSI really measure chest movement since it is very weak?
- Yes the CSI changes caused by breathing rate is very weak. However, we have multiple subcarriers for both 2.4GHz & 5GHz with whatever bandwidth (usually, 20MHz, 40MHz, 80MHz). As a result, we design a subcarrier selection method and futher using a maximum-ratio combining (MRC) to boost the vital signs.
3. Have you tested your system using practical measurements?
- The research was then developed as a Sleep Monitoring System and commercialized as Origin Health for Remote Patient Monitoring by Origin Wireless AI Inc., which won the CES 2021 Best of Innovation Award.
Key words: Vital Signs, CSI, Sleep Monitoring.