Venkat Arun, Hari Balakrishnan
17th USENIX Symposium on Networked Systems Design and Implementation, Santa Clara, CA, February 2020
To reduce transmit power, increase throughput, and improve
range, radio systems benefit from the ability to direct more
of the transmitted power toward the intended receiver. Many
modern systems beamform with antenna arrays for this
purpose. However, a radio’s ability to direct its signal is
fundamentally limited by its size. This limitation is acute on
IoT and mobile devices, which are small and inexpensive, but
even access points and base stations are typically constrained
to a modest number of antennas.
To address this problem, we introduce RFocus, which
moves beamforming functions from the radio endpoints to
the environment. RFocus includes a two-dimensional surface
with a rectangular array of simple RF switch elements. Each
switch element either lets the signal through or reflects it. The
surface does not emit any power of its own. The state of the
elements is set by a software controller to maximize the signal
strength at a receiver, with a novel optimization algorithm
that uses signal strength measurements from the receiver. The
RFocus surface can be manufactured as an inexpensive thin
“wallpaper”. In one floor of an office building (at MIT CSAIL),
our prototype improves the median signal strength by 9.5×
and the median channel capacity by 2.0×.
[PDF (0KB)]
Bibtex Entry:
@inproceedings{arun2020rfocus,
author = "Venkat Arun and Hari Balakrishnan",
title = "{RFocus: Beamforming Using Thousands of Passive Antennas}",
booktitle = {17th USENIX Symposium on Networked Systems Design and Implementation},
year = {2020},
month = {February},
address = {Santa Clara, CA}
}