When Can We Detect Human Respiration With Commodity Wifi Devices?

Recent research has demonstrated the feasibility of detecting human respiration rate non-intrusively using commodity WiFi devices. However, it is not always possible to sense human respiration when a subject is in different locations or faces different orientations. In this demo. we will show how a centimeter-scale position change affects the respiration detection performance. Counter-intuitively, when a subject is moving closer to the LoS. the performance of respiration sensing is not always getting better. In fact, the detectable and undetectable regions are determined by the Fresnel zone model based theory developed in [7].