μMote: Enabling Passive Chirp De-spreading and μW-level Long-Range Downlink for Backscatter Devices

Authors: 

Yihang Song and Li Lu, University of Electronic Science and Technology of China; Jiliang Wang, Tsinghua University; Chong Zhang, Hui Zheng, and Shen Yang, University of Electronic Science and Technology of China; Jinsong Han, Zhejiang University; Jian Li, University of Electronic Science and Technology of China

Abstract: 

The downlink range of backscatter devices is commonly considered to be very limited, compared to tremendous long-range and low-power backscatter uplink designs that leverage the chirp spread spectrum (CSS) principle. Recently, some efforts are devoted to enhancing the downlink, but they are unable to achieve long-range receiving and low power consumption simultaneously. In this paper, we propose µMote, a µW-level long-range receiver for backscatter devices. µMote achieves the first passive chirp de-spreading scheme for negative SINR in long-range receiving scenarios. Further, without consuming external energy, µMote magnifies the demodulated signal by accumulating temporal energy of the signal itself in a resonator container, and meanwhile it preserves signal information during this signal accumulation. µMote then leverages a µW-level sampling-less decoding scheme to discriminate symbols, avoiding the high-power ADC-sampling. We prototype µMote with COTS components, and conduct extensive experiments. The result shows that µMote spends an overall power consumption of 62.07µW to achieve a 400m receiving range at a 2kbps data rate with 1% BER, under −2dB SINR

NSDI '23 Open Access Sponsored by
King Abdullah University of Science and Technology (KAUST)

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BibTeX
@inproceedings {286437,
author = {Yihang Song and Li Lu and Jiliang Wang and Chong Zhang and Hui Zheng and Shen Yang and Jinsong Han and Jian Li},
title = {{μMote}: Enabling Passive Chirp De-spreading and {μW-level} {Long-Range} Downlink for Backscatter Devices},
booktitle = {20th USENIX Symposium on Networked Systems Design and Implementation (NSDI 23)},
year = {2023},
isbn = {978-1-939133-33-5},
address = {Boston, MA},
pages = {1751--1766},
url = {https://www.usenix.org/conference/nsdi23/presentation/song-yihang},
publisher = {USENIX Association},
month = apr
}

Presentation Video