Battery-Less Location Tracking for Internet of Things: Simultaneous Wireless Power Transfer and Positioning
We propose a battery-less location tracking system that enables 3-D positioning of an Internet of Things (IoT) device powered by the radio frequency (RF) wireless power transfer (WPT). In the proposed system, a power beacon is equipped with a phased antenna array that has the dual purposes of high-e...
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Veröffentlicht in: | IEEE internet of things journal 2019-10, Vol.6 (5), p.9147-9164 |
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Sprache: | eng |
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Zusammenfassung: | We propose a battery-less location tracking system that enables 3-D positioning of an Internet of Things (IoT) device powered by the radio frequency (RF) wireless power transfer (WPT). In the proposed system, a power beacon is equipped with a phased antenna array that has the dual purposes of high-efficiency WPT and phase-based accurate positioning. In order to enhance the efficiency of the RF WPT, we propose a beam focusing algorithm that dynamically controls the respective phases of antenna elements to place the focal point of the electro-magnetic (EM) wave onto the target IoT device. We also propose a phase-based positioning algorithm that requires only one multiantenna anchor point for determining the distance as well as the direction from the anchor point. We analyze the Cramer-Rao lower bound (CRLB) of the phase-based positioning with a single multiantenna anchor point, and show that the distance from the anchor point can be estimated as long as the IoT device lies within the radiative near-field region. We propose a joint location tracking and WPT algorithm that performs 3-D positioning and beam-focused WPT in a unified way. We have built a real-life testbed with a large-scale antenna array with 64 antenna elements for testing the proposed algorithm. The experimental results show the effectiveness of the proposed algorithm in a real environment. |
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ISSN: | 2327-4662 2327-4662 |
DOI: | 10.1109/JIOT.2019.2928313 |