Fine-grained vital signs estimation using commercial wi-fi devices

Due to the importance of vital signs, breathing rate and heart rate have been widely used in heath care. In the past few years, various systems and approaches have been proposed to detect and monitor breath and heart beat. In this paper, we show that Wi-Fi signals can also be used to recognize and count breath and heart beats with different postures. The intuition is that human activities have different impacts on time-series of Channel State Information (CSI) values, which can be utilized to recognize macro and micro human activities. In this paper, we design a Wi-Fi signal based breath and heart beats recognition system called Wi-Health. WiHeath consists of two Commercial Off-The-Shelf (COTS) Wi-Fi devices, a sender (Wi-Fi router) and a receiver (laptop). The sender sends 802.11n packets to the receiver, while the receiver continuously receives these packets and records in real-time CSI value. The receiver analyzes the collected CSI values and determines if the human is alive and the number of heart beats and breaths.