Thin Film Reconfigurable Intelligent Surface Assisted Device-Free Fall Detection

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A4 Artikkeli konferenssijulkaisussa

Date

2024-12

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Language

en

Pages

4

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2024 IEEE Sensors, Proceedings of IEEE Sensors

Abstract

Fall detection is essential for safeguarding vulnerable populations, such as the elderly. We design and implement a low-complexity reconfigurable intelligent surface (RIS)-assisted fall detection system. The manufactured thin film 4X1 RIS can effectively control the scattering of the dominant harmonics of the captured radio frequency (RF) carrier wave by steering their beams to a desired direction ranging from 230° to 310° in elevation. With beam steering, the RIS enables device-free fall detection by conducting dynamic elevation beam-scanning in an indoor space and analyzing variations in received signal strength (RSS) caused by human presence and motion, without requiring the person to carry any sensors or electronic devices. We design a posture recognition-based fall detection algorithm. Experimental results show that using a simple support vector machine (SVM) classifier can achieve 92.50% accuracy in significant posture recognition that includes standing, sitting, and lying. Five voluntary participants were used for cross-validation. Compared with a conventional sensor node pair-based solution with a static beam, our proposed dynamic beam scanning technique improves accuracy by 11.83% using SVM. The results indicate that the RIS and the proposed algorithm have the potential to facilitate fall detection applications for assisted living.

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Keywords

device-free RF sensing, integrated sensing and communication (ISAC), printed electronics, received signal strength, Fall detection, reconfigurable intelligent surface (RIS)

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Citation

Xie, B, Bai, Y, Li, X, Mela, L, Rimpiläinen, T & Jäntti, R 2024, Thin Film Reconfigurable Intelligent Surface Assisted Device-Free Fall Detection . in 2024 IEEE Sensors . Proceedings of IEEE Sensors, IEEE, IEEE SENSORS, Kobe, Japan, 20/10/2024 . https://doi.org/10.1109/SENSORS60989.2024.10784629