Abstract
Recent years have witnessed the evolution of WiFi technologies, accompanied by the emergence and progress of WiFi-based sensing applications. However, the advancement of the IEEE 802.11 standards has brought along new features to mainstream commodity WiFi devices that may invalidate existing state-of-the-art methods, which has become one of the main challenges for real-life adoption of WiFi sensing. Therefore, it is essential to ensure WiFi sensing keep in step with the latest WiFi standards. In this paper, we uncover the new features on commodity WiFi 6E devices dissimilar from legacy IEEE 802.11n/ac/ax devices that most existing works focus on. We conduct experiments to find the reasons and behavior patterns of the new features (i.e., the four-way phase ambiguity) and propose our solutions accordingly. We take the fine-grained respiration sensing as a demonstration, and experimental results verify the effectiveness of our approach. Our approach is not application-specific so it could also benefit other WiFi sensing applications.