Enabling Ubiquitous WiFi Sensing with Beamforming Reports

Wi-Fi sensing systems leverage wireless signals from widely deployed Wi-Fi devices to realize sensing for a broad range of applications. However, current Wi-Fi sensing systems heavily rely on the channel state information (CSI) to learn the signal propagation characteristics, while the availability of CSI is highly dependent on specific Wi-Fi chipsets. Through a city-scale measurement, we discover that the availability of CSI is extremely limited in operational Wi-Fi devices. In this work, we propose a new wireless sensing system called BeamSense that exploits the compressed beamforming reports (CBR). Due to the extensive support of transmit beamforming in operational Wi-Fi devices, CBR is commonly accessible and hence enables a ubiquitous sensing capability. BeamSense adopts a novel multi-path estimation algorithm that can efficiently and accurately map bidirectional CBR to a multi-path channel based on intrinsic fingerprints. We implement BeamSense on several prevalent models of Wi-Fi devices and evaluated its performance with microbenchmarks and three representative Wi-Fi sensing applications. The results show that BeamSense is capable of enabling existing CSI-based sensing algorithms to work with CBR with high sensing accuracy and improved generalizability.