Fast and Precise Direction of Arrival Estimation Based on Space and Frequency Division Multiple Access

This paper introduces a cost-effective method for estimating the range and direction of arrival (DoA). The method is based on the received signal strength indicator and uses a single anchor node. Using space division multiple access through an anchor node with a switched beam front-end, the DoA of a mobile node is determined using a maximum likelihood criterion, guided by the expected signal distribution for a link between the anchor and the node. To enhance the robustness of the approach, two distinct DoA estimation algorithms operating at four frequencies are combined. The proposed method enables low-cost absolute position estimation, making it particularly suitable for wireless sensor networks and IEEE 802.11n/ac-compliant networks. The experimental results validate the effectiveness of the method, demonstrating a mean error of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{2. 7 5}^{\circ}$</tex> and approximately <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{9 0 \%}$</tex> localization coverage within 5.2° in a typical home environment of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$38 ~\mathrm{m}^{2}$</tex>. These findings confirm that the proposed system offers an affordable solution without the need of a multi-anchor setup.