Device-Free Localization with Multiple Antenna Receivers: Simulations and Results

Device-Free Localization (DFL) is a passive radio method able to detect, estimate, and localize targets (e.g., human or other obstacles) that do not need to carry any electronic device. According to the Integrated Sensing And Communication (ISAC) paradigm, DFL networks exploit Radio Frequency (RF) devices, used for communication purposes, to evaluate also the excess attenuation due to targets moving in the monitored area, to estimate the target positions and movements. Several target models have been discussed in the literature to evaluate the target positions by exploiting the RF signals received by networked devices. Among these models, Electromagnetic (EM) body models emerged as an interesting research field for excess attenuation prediction using commercial RF devices. While these RF devices are usually single-antenna boards, the availability of low-cost multi-antenna devices e.g. those used in WLAN (Wireless Local Area Network) scenarios, allow us to exploit array-based signal processing techniques for DFL applications as well. Using an array-capable EM body model, this paper shows how to employ array-based processing to improve angular detection of targets. Unlike single-antenna devices that can provide only attenuation information, multi-antenna devices can provide both angular and attenuation estimates about the target location. To this end, simulations are presented and preliminary results are discussed. The proposed framework paves the way for a wider use of multi-antenna devices based, for instance, on WiFi6 and WiFi7 standards.