124 research outputs found
MIMO Transmission through Reconfigurable Intelligent Surface: System Design, Analysis, and Implementation
Reconfigurable intelligent surface (RIS) is a new paradigm that has great
potential to achieve cost-effective, energy-efficient information modulation
for wireless transmission, by the ability to change the reflection coefficients
of the unit cells of a programmable metasurface. Nevertheless, the
electromagnetic responses of the RISs are usually only phase-adjustable, which
considerably limits the achievable rate of RIS-based transmitters. In this
paper, we propose an RIS architecture to achieve amplitude-and-phase-varying
modulation, which facilitates the design of multiple-input multiple-output
(MIMO) quadrature amplitude modulation (QAM) transmission. The hardware
constraints of the RIS and their impacts on the system design are discussed and
analyzed. Furthermore, the proposed approach is evaluated using our prototype
which implements the RIS-based MIMO-QAM transmission over the air in real time.Comment: This paper aims to investigate the feasibility of using RIS for MIMO
wireless transmission for higher-order modulation by presenting an analytical
modeling of the RIS-based system and providing experimental results from a
prototype which has been buil
Design of Reconfigurable Intelligent Surfaces for Wireless Communication: A Review
Existing literature reviews predominantly focus on the theoretical aspects of
reconfigurable intelligent surfaces (RISs), such as algorithms and models,
while neglecting a thorough examination of the associated hardware components.
To bridge this gap, this research paper presents a comprehensive overview of
the hardware structure of RISs. The paper provides a classification of RIS cell
designs and prototype systems, offering insights into the diverse
configurations and functionalities. Moreover, the study explores potential
future directions for RIS development. Notably, a novel RIS prototype design is
introduced, which integrates seamlessly with a communication system for
performance evaluation through signal gain and image formation experiments. The
results demonstrate the significant potential of RISs in enhancing
communication quality within signal blind zones and facilitating effective
radio wave imaging
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