Reconfigurable Intelligent Surfaces for Energy Efficiency in Wireless Communication

By Chongwen Huang, Alessio Zappone, George C. Alexandropoulos, Merouane Debbah, Chau Yuen. IEEE Transactions on Wireless Communications, 2018

2,870 citations recorded by the source corpus.

The adoption of a reconfigurable intelligent surface (RIS) for downlink multi-user communication from a multi-antenna base station is investigated in this paper. We develop energy-efficient designs for both the transmit power allocation and the phase shifts of the surface reflecting elements subject to individual link budget guarantees for the mobile users. This leads to non-convex design optimization problems for which to tackle we propose two computationally affordable approaches, capitalizing on alternating maximization, gradient descent search, and sequential fractional programming. Specifically, one algorithm employs gradient descent for obtaining the RIS phase coefficients, and fractional programming for optimal transmit power allocation. Instead, the second algorithm employs sequential fractional programming for the optimization of the RIS phase shifts. In addition, a realistic power consumption model for RIS-based systems is presented, and the performance of the proposed methods is analyzed in a realistic outdoor environment. In particular, our results show that the proposed RIS-based resource allocation methods are able to provide up to 300% higher energy efficiency in comparison with the use of regular multi-antenna amplify-and-forward relaying.

View Paper: https://www.semanticscholar.org/paper/29a169de88d8b61104bd71b3a4de89269f947249

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Citations in the corpus

Holographic MIMO Surfaces for 6G Wireless Networks: Opportunities, Challenges, and Trends (2019, methodology): “simulation parameters are shown in Table II [5].”
Channel Estimation and Passive Beamforming for Intelligent Reflecting Surface: Discrete Phase Shift and Progressive Refinement (2019, background): “, [6], [7], [15]–[27]) have mostly assumed perfect CSI available for all the individual channels between the IRS and its aided access point (AP) as well as users, which,”
Intelligent Reflecting Surface Versus Decode-and-Forward: How Large Surfaces are Needed to Beat Relaying? (2019, methodology): “5, Ps = Pd = Pr = 100 mW, Pe = 5 mW [11], and d1 = 70 m.”
STAR-RISs: Simultaneous Transmitting and Reflecting Reconfigurable Intelligent Surfaces (2021, background): “There are diverse applications of introducing RISs into wireless networks, including but not limited to energy efficiency enhancement [4], multi-user support [5], visible light communication [6], and robotic communication [7].”
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How it Works, State of Research, and Road Ahead (2020, background): “In [143], [144], the authors consider the maximization of the spectral and energy efficiency in a multi-user MISO downlink network, by alternatively optimizing the base station beamforming and the RIS phase shifts.”
Compressed Channel Estimation for Intelligent Reflecting Surface-Assisted Millimeter Wave Systems (2020, background): “INTELLIGENT reflecting surface (IRS) comprising a large number of passive reflecting elements is emerging as a promising technology for realizing a smart and programmable wireless propagation environment via software-controlled reflection [1]–[4].”
Enabling Large Intelligent Surfaces With Compressive Sensing and Deep Learning (2019, methodology): “The large intelligent surfaces are envisioned as key components of future networks [5].”
Reconfigurable Intelligent Surface Assisted UAV Communication: Joint Trajectory Design and Passive Beamforming (2019, background): “2966705 To improve the propagation environment and enhance communication quality, reconfigurable intelligent surface (RIS) has attracted extensive attention [4]–[6].”
Reconfigurable Intelligent Surface-Based Index Modulation: A New Beyond MIMO Paradigm for 6G (2019, unknown): “The authors of [14]–[16] considered an RIS-assisted downlink transmission scenario to support multiple users and focused on the maximization of sumrate and energy efficiency.”
Reconfigurable Intelligent Surfaces: A signal processing perspective with wireless applications (2021, unknown): “RIS is an umbrella term that recently appeared in the communication domain [14], but the technology has deep roots in the electromagnetic field [4], [11], [15], [16].”
Joint Transmit Waveform and Passive Beamforming Design for RIS-Aided DFRC Systems (2021, background): “Motivated by the above, the applications of RIS in various wireless communication scenarios have been widely studied, including but not limited to the designs for maximizing spectral efficiency [10], [11], sum-rate [12]-[14], energy efficiency [15], [16], and minimizing transmit power [17], [18], et”
Secure Wireless Communication via Intelligent Reflecting Surface (2019, background): “, transmit power minimization [4]–[6] and energy efficiency maximization [7].”
Intelligent Reflecting Surface: Practical Phase Shift Model and Beamforming Optimization (2019, background): “It is not difficult to observe that for the ideal phase shift model considered in [2]–[4], βn(θn) and θn can be designed to maximize f(θn) (or (13)) by setting β∗ n(θn) = 1 and θ ∗ n = arg(φn), ∀n.”