Investigations of a Phase-Less Direction of Arrival Estimation System for Context-Aware Applications in the 5 GHz Wi-Fi Spectrum

The paper presents a cost-effective direction-of-arrival (DoA) estimation technique tailored for systems operating within the 5 GHz Wi-Fi spectrum. Leveraging the dual role of Wi-Fi infrastructure for both connectivity and environmental sensing, the method aligns with the paradigm of joint communications and sensing (JCAS). The system relies on a single anchor node and uses the received signal strength indicator as the key observable for spatial inference. To achieve angular localization, the anchor node is equipped with a switched-beam front end that implements space-division multiple access. This setup enables DoA estimation using a maximum likelihood criterion based on the spatial distribution of the received signal. Robustness is further enhanced through the integration of multiple complementary DoA algorithms, each operating across distinct frequency channels within the 5 GHz band. The proposed JCAS-based method provides low-cost absolute positioning, particularly suited for wireless sensor networks and indoor environments relying on commodity Wi-Fi hardware. Experimental evaluations conducted in a representative home scenario spanning 38 m2 yield a mean angular error of 1.29° and approximately 95% coverage within 3.12°, validating the system’s ability to deliver accurate localization without the need for multiple anchors.