RIScatter: unifying backscatter communication and reconfigurable intelligent surface
File(s)
Published version
Author(s)
Zhao, Yang
Clerckx, Bruno
Type
Working Paper
Abstract
Backscatter Communication (BackCom) nodes harvest energy from and modulate
information over an external electromagnetic wave. Reconfigurable Intelligent
Surface (RIS) adapts its phase shift response to enhance or attenuate channel
strength in specific directions. In this paper, we show how those two seemingly
different technologies (and their derivatives) can be unified to leverage their
benefits simultaneously into a single architecture called RIScatter. RIScatter
consists of multiple dispersed or co-located scatter nodes, whose reflection
states can be adapted to partially engineer the wireless channel of the
existing link and partially modulate their own information onto the scattered
wave. This contrasts with BackCom (resp. RIS) where the reflection pattern is
exclusively a function of the information symbol (resp. Channel State
Information (CSI)). The key principle in RIScatter is to render the probability
distribution of reflection states (i.e., backscatter channel input) as a joint
function of the information source, CSI, and Quality of Service (QoS) of the
coexisting active primary and passive backscatter links. This enables RIScatter
to softly bridge, generalize, and outperform BackCom and RIS; boil down to
either under specific input distribution; or evolve in a mixed form for
heterogeneous traffic control and universal hardware design. For a single-user
multi-node RIScatter network, we characterize the achievable
primary-(total-)backscatter rate region by optimizing the input distribution at
the nodes, the active beamforming at the Access Point (AP), and the backscatter
detection regions at the user. Simulation results demonstrate RIScatter nodes
can exploit the additional propagation paths to smoothly transition between
backscatter modulation and passive beamforming.
information over an external electromagnetic wave. Reconfigurable Intelligent
Surface (RIS) adapts its phase shift response to enhance or attenuate channel
strength in specific directions. In this paper, we show how those two seemingly
different technologies (and their derivatives) can be unified to leverage their
benefits simultaneously into a single architecture called RIScatter. RIScatter
consists of multiple dispersed or co-located scatter nodes, whose reflection
states can be adapted to partially engineer the wireless channel of the
existing link and partially modulate their own information onto the scattered
wave. This contrasts with BackCom (resp. RIS) where the reflection pattern is
exclusively a function of the information symbol (resp. Channel State
Information (CSI)). The key principle in RIScatter is to render the probability
distribution of reflection states (i.e., backscatter channel input) as a joint
function of the information source, CSI, and Quality of Service (QoS) of the
coexisting active primary and passive backscatter links. This enables RIScatter
to softly bridge, generalize, and outperform BackCom and RIS; boil down to
either under specific input distribution; or evolve in a mixed form for
heterogeneous traffic control and universal hardware design. For a single-user
multi-node RIScatter network, we characterize the achievable
primary-(total-)backscatter rate region by optimizing the input distribution at
the nodes, the active beamforming at the Access Point (AP), and the backscatter
detection regions at the user. Simulation results demonstrate RIScatter nodes
can exploit the additional propagation paths to smoothly transition between
backscatter modulation and passive beamforming.
Date Issued
2022-12-18
Citation
2022
Publisher
arXiv
Copyright Statement
© 2022 The Author(s). This work is published under a CC BY-NC-SA licence.
Identifier
http://arxiv.org/abs/2212.09121v2
Subjects
cs.IT
cs.IT
eess.SP
math.IT
Publication Status
Published