802.11bf Multiband Passive Sensing: Reusing Wi-Fi Signaling for Sensing

This paper presents a novel multiband passive sensing system that leverages IEEE 802.11bf Wi-Fi signals for environmental sensing, focusing on both sub-7 GHz and millimeter-wave (mmWave) bands. By combining Channel State Information (CSI) from multiple bands, the system enhances accuracy and reliability in detecting human presence, movement, and activities in indoor environments. Utilizing a novel model, called MILAGRO, the system demonstrates robust performance across different scenarios, including monitoring human presence in workspaces and tracking movement in corridors. Experimental results show high accuracy (95-100%), with improved performance by integrating multiband data. The system also addresses key security concerns associated with passive sensing, proposing measures to mitigate potential risks. This work advances the use of Wi-Fi for passive sensing by reducing reliance on active sensing infrastructure and extending the capabilities of low-cost, non-intrusive environmental monitoring.