Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming

By Qingqing Wu, Rui Zhang. IEEE Transactions on Wireless Communications, 2018

4,111 citations recorded by the source corpus.

Intelligent reflecting surface (IRS) is a revolutionary and transformative technology for achieving spectrum and energy efficient wireless communication cost-effectively in the future. Specifically, an IRS consists of a large number of low-cost passive elements each being able to reflect the incident signal independently with an adjustable phase shift so as to collaboratively achieve three-dimensional (3D) passive beamforming without the need of any transmit radio-frequency (RF) chains. In this paper, we study an IRS-aided single-cell wireless system where one IRS is deployed to assist in the communications between a multi-antenna access point (AP) and multiple single-antenna users. We formulate and solve new problems to minimize the total transmit power at the AP by jointly optimizing the transmit beamforming by active antenna array at the AP and reflect beamforming by passive phase shifters at the IRS, subject to users’ individual signal-to-interference-plus-noise ratio (SINR) constraints. Moreover, we analyze the asymptotic performance of IRS’s passive beamforming with infinitely large number of reflecting elements and compare it to that of the traditional active beamforming/relaying. Simulation results demonstrate that an IRS-aided MIMO system can achieve the same rate performance as a benchmark massive MIMO system without using IRS, but with significantly reduced active antennas/RF chains. We also draw useful insights into optimally deploying IRS in future wireless systems.

Subfields: Aerospace Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/2006b6cad640274d88195b7520bacaac4711c2ce

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Citations in the corpus

Reconfigurable Intelligent Surface Assisted Multiuser MISO Systems Exploiting Deep Reinforcement Learning (2020, methodology): “Instead, in general, algorithms are developed to find out suboptimal solutions employing alternating optimization techniques to maximize the objective functions, where in each iteration, suboptimal G is solved by first fixing Φ [15][20] while suboptimal Φ is derived by fixing the G, until the algori”
Multicell MIMO Communications Relying on Intelligent Reflecting Surfaces (2019, background): “Most recently, some initial efforts have been devoted to the transmitter design of IRS-assisted wireless communication systems, including the single-user case of [15]–[18], the downlink multiuser case of [19]–[23], wireless power transfer design of [24], mobile edge computing of [25], multicast scen”
Towards Smart and Reconfigurable Environment: Intelligent Reflecting Surface Aided Wireless Network (2019, methodology): “To reduce such high complexity, alternating optimization can be applied to obtain suboptimal solutions, by iteratively optimizing one of the transmit and reflect beamforming with the other being fixed, until the convergence is reached [4].”
The Roadmap to 6G Security and Privacy (2021, background): “Possible Solutions: By controlling the phase shifts of RIS in an intelligent manner, the reflected signals can either be added coherently at the intended receiver to enhance the quality of the received signal, or be added destructively at a non-desired receiver to enhance security [145].”
Reconfigurable Intelligent Surfaces: Principles and Opportunities (2020, methodology): “Scenarios Phase shifts CSI Main Objectives Techniques/Characteristics [73] SU/MU-DL-MISO Continuous Perfect Transmit power AO-SDR-based algorithm and two stage algorithm [74] SU/MU-DL-MISO Discrete Perfect Transmit power Near-optimal ZF-based successive refinement method [75] MU-DL-MISO Continuous P”
Compressed Channel Estimation for Intelligent Reflecting Surface-Assisted Millimeter Wave Systems (2020, background): “Each reflecting element of the IRS can reflect the incident signal with a reconfigurable phase shift and amplitude via a smart controller [3].”
A Joint Precoding Framework for Wideband Reconfigurable Intelligent Surface-Aided Cell-Free Network (2020, methodology): “We further assume ωBR → ∞, ωBu = 0 and, ωRu = 0 [32].”
Active Reconfigurable Intelligent Surface-Aided Wireless Communications (2021, background): “The above problem has been well investigated in [9] and efficiently solved by alternating optimization technique.”
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead (2020, background): “In [157], the authors address the problem of minimizing the base station power consumption with respect to the base station beamformer and the RIS phase shifts, subject to mini-”
RIS-Aided Wireless Communications: Prototyping, Adaptive Beamforming, and Indoor/Outdoor Field Trials (2021, methodology): “If a continuous phase-shift optimization is possible, then the optimal phaseshift vector is given as [11], [30]”
Grant-Free Non-Orthogonal Multiple Access for IoT: A Survey (2019, background): “4) Reconfigurable Intelligent Surfaces: Reconfigurable intelligent surfaces (RIS, [237]), also known as large intelligent metasurfaces (LIM, [238]) and intelligent reflecting surfaces (IRS, [239]), have been considered as a potential technology for improving the energy and spectral efficiencies of w”
Path Loss Modeling and Measurements for Reconfigurable Intelligent Surfaces in the Millimeter-Wave Frequency Band (2021, methodology): “By letting d1 = 1 m or d1 = 2 m, and varying d2 in the range [1, 5] m, we have measured the received power as a function of d1 and d2.”
Intelligent Reflecting Surface: A Programmable Wireless Environment for Physical Layer Security (2019, background): “, traditional reflecting surfaces [7], amplify-and-forward (AF) relay [8], active intelligent surface [9], and backscatter communication [10]–[12], IRS has the following advantages [13], [14].”
Holographic MIMO Communications: Theoretical Foundations, Enabling Technologies, and Future Directions (2022, background): “We recommend readers to refer to a multitude of overview, survey and tutorial papers seeking the advances of RIS/IRS [43]–[84].”