Pushing the Physical Limits of IoT Devices with Programmable Metasurfaces


Lili Chen, Northwest University (China) and University of Massachusetts Amherst; Wenjun Hu, Yale University; Kyle Jamieson, Princeton University; Xiaojiang Chen and Dingyi Fang, Northwest University (China); Jeremy Gummeson, University of Massachusetts Amherst


Small, low-cost IoT devices are typically equipped with only a single, low-quality antenna, significantly limiting communication range and link quality. In particular, these antennas are typically linearly polarized and therefore susceptible to polarization mismatch, which can easily cause 10-15 dBm of link loss on communication to and from such devices. In this work, we highlight this under-appreciated issue and propose the augmentation of IoT deployment environments with programmable, RF-sensitive surfaces made of metamaterials. Our smart metasurface mitigates polarization mismatch by rotating the polarization of signals that pass through or reflects off the surface. We integrate our metasurface into an IoT network as LLAMA, a Low-power Lattice of Actuated Metasurface Antennas, designed for the pervasively used 2.4 GHz ISM band. We optimize LLAMA's metasurface design for both low transmission loss and low cost, to facilitate deployment at scale. We then build an end-to-end system that actuates the metasurface structure to optimize for link performance in real-time. Our experimental prototype-based evaluation demonstrates gains in link power of up to 15 dB, and wireless capacity improvements of 100 and 180 Kbit/s/Hz in through-surface and surface-reflective scenarios, respectively, attributable to the polarization rotation properties of LLAMA's metasurface.

NSDI '21 Open Access Sponsored by NetApp

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@inproceedings {262044,
author = {Lili Chen and Wenjun Hu and Kyle Jamieson and Xiaojiang Chen and Dingyi Fang and Jeremy Gummeson},
title = {Pushing the Physical Limits of {IoT} Devices with Programmable Metasurfaces},
booktitle = {18th USENIX Symposium on Networked Systems Design and Implementation (NSDI 21)},
year = {2021},
isbn = {978-1-939133-21-2},
pages = {425--438},
url = {https://www.usenix.org/conference/nsdi21/presentation/chen},
publisher = {USENIX Association},
month = apr

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