Device-free localization (DFL) is a wireless sensing technique that determines the position or movement of individuals within an environment without requiring them to carry or interact with any dedicated electronic device, instead relying on perturbations to ambient radio frequency signals such as WiFi to infer location. It matters significantly to the field because it enables passive, unobtrusive monitoring for applications including indoor navigation, emergency response, and smart building management, removing the burden of device ownership or cooperation from the target. Key variants include range-based approaches that estimate location from signal attenuation or time-of-flight measurements, fingerprinting methods that match observed channel state information patterns to pre-built spatial maps, and motion-detection-driven localization that first identifies movement events before refining positional estimates, with emerging IEEE 802.11bf standardization efforts aiming to make such capabilities interoperable across multi-vendor WiFi deployments.
Source Papers
- Channel State Information from Pure Communication to Sense and Track Human Motion: A Survey ↗ — Channel State Information from Pure Communication to Sense a
- OPERAnet, a multimodal activity recognition dataset acquired from radio frequency and vision-based sensors ↗ — OPERAnet, a multimodal activity recognition dataset acquired
- WiFi Sensing with Channel State Information ↗ — WiFi Sensing with Channel State Information