WiFi-Based People Counting Using Beam-Steerable Antennas: A Test-bed Study
It addresses the problem of non-intrusive people counting for smart environments, but the results are incremental as they rely on existing CSI-based methods with a new antenna configuration.
This paper presents a test-bed study for people counting using beam-steerable antennas and Wi-Fi signals, demonstrating that beam-steerable antennas improve counting accuracy compared to fixed antennas, achieving up to 95% accuracy for up to 5 people.
Ubiquitous perception through RF signals is a pivotal opportunity for future technology: it enables personalized services such as smart living, remote healthcare, automated logistics or interaction through free-space gestures. The ubiquity of Wi-Fi and cellular networks presents a promising platform for the development of innovative sensing tools. Future standards will also introduce dedicated sensing features which, for example, will allow routers to work as frequency modulated continuous wave radios targeting radar applications. Most of the current chip designs support ad-hoc firmware for CSI extraction with MIMO arrangements of the transmitter (TX) and receiver (RX) antennas and OFDM subcarriers. The CSI describes the phase shift and amplitude attenuation of multiple propagation paths on each subcarrier. The latest IEEE 802.11be standard (Wi-Fi 7) offers a wider subcarrier bandwidth of 160MHz (up to 320MHz), providing at least 120 usable pilot subcarriers for CSI or CIR estimation. Additionally, Wi-Fi signals have been recently exploited to track daily human movements and behaviors, while Wi-Fi signal variations have been shown to differ between different people and can consequently be used for their re-identification.