Joint Active and Passive Beamforming Optimization for Intelligent Reflecting Surface Assisted SWIPT Under QoS Constraints

By Qingqing Wu, Rui Zhang. IEEE Journal on Selected Areas in Communications, 2019

504 citations recorded by the source corpus.

Intelligent reflecting surface (IRS) is a new and revolutionizing technology for achieving spectrum and energy efficient wireless networks. By leveraging massive low-cost passive elements that are able to reflect radio-frequency (RF) signals with adjustable phase shifts, IRS can achieve high passive beamforming gains, which are particularly appealing for improving the efficiency of RF-based wireless power transfer. Motivated by the above, we study in this paper an IRS-assisted simultaneous wireless information and power transfer (SWIPT) system. Specifically, a set of IRSs are deployed to assist in the information/power transfer from a multi-antenna access point (AP) to multiple single-antenna information users (IUs) and energy users (EUs), respectively. We aim to minimize the transmit power at the AP via jointly optimizing its transmit precoders and the reflect phase shifts at all IRSs, subject to the quality-of-service (QoS) constraints at all users, namely, the individual signal-to-interference-plus-noise ratio (SINR) constraints at IUs and the energy harvesting constraints at EUs. However, this optimization problem is non-convex with intricately coupled variables, for which the existing alternating optimization approach is shown to be inefficient as the number of QoS constraints increases. To tackle this challenge, we first apply proper transformations on the QoS constraints and then propose an efficient iterative algorithm by applying the penalty-based optimization method. Moreover, by exploiting the short-range coverage of IRS, we further propose a more computationally efficient algorithm by optimizing the phase shifts at all IRSs in parallel. Simulation results demonstrate the effectiveness of employing multiple IRSs for enhancing the performance of SWIPT systems as well as the significant performance gains achieved by our proposed algorithms over benchmark schemes. The impact of IRS on the transmitter/receiver design for SWIPT is also unveiled.

Subfields: Aerospace Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/d4e0ef6c67a6109af521cf3124a8bb541c47730b

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Citations in the corpus

Intelligent Reflecting Surface Enhanced Wireless Networks: Two-Timescale Beamforming Optimization (2019, background): “multiplexing (OFDM) system [14], [15], IRS-aided mmWave communications [16], physical layer security [17]–[20], wireless power transfer [21]–[24], and so on.”
Toward Smart Wireless Communications via Intelligent Reflecting Surfaces: A Contemporary Survey (2019, background): “Instead of sum-rate maximization, the authors in [186] focus on the AP’s transmit power minimization by jointly optimizing the AP’s transmit beamforming and the IRSs’ passive beamforming, subject to the IRs’ SINR constraints and the ERs’ energy constraints.”
Joint Transmit Waveform and Passive Beamforming Design for RIS-Aided DFRC Systems (2021, background): “[19] Q. Wu and R. Zhang, “Joint active and passive beamforming optimization for intelligent reflecting surface and SWIPT under QoS constraints,” IEEE J. Sel.”
Intelligent Reflecting Surface-Aided Wireless Communications: A Tutorial (2020, methodology): “Moreover, the improvement of wireless charging efficiency in turn helps reduce the transmit power as well as provide more flexibility in designing the transmit beamforming for information receivers and thus improves both the rate and energy performance in SWIPT systems [66], [128]–[130].”
Holographic MIMO Communications: Theoretical Foundations, Enabling Technologies, and Future Directions (2022, background): “Various holographic beamforming schemes were proposed in wireless communications [248], [270], [321], however, the existing work mainly focuses on angle-aware beamforming schemes, i.”
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead (2020, background): “In [234], the authors analyze the downlink of a MISO”
An Overview of Signal Processing Techniques for RIS/IRS-Aided Wireless Systems (2021, unknown): “cell systems [107], [152], [153], physical layer security systems [89], [93], [94], [103], [104], [154], [155], simultaneous wireless information and power transfer (SWIPT) [105], [114], [119], [156]–[160], mobile edge computing networks [80], [117], [161]–[166], multicast networks [102], [167], cog”
Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How it Works, State of Research, and Road Ahead (2020, background): “In [233], the authors analyze the downlink of a MISO system in which the simultaneous transmission of information and power is considered.”
Reconfigurable Intelligent Surfaces: Principles and Opportunities (2020, methodology): “[22] extended the RIS-assisted SWIPT system with multiple RISs, where the transmit power was minimized while satisfying the different QoS constraints at information users and energy users.”
Modeling and Architecture Design of Reconfigurable Intelligent Surfaces Using Scattering Parameter Network Analysis (2020, background): “…areas such as secure wireless communication [15], backscatter communication [16], simultaneous wireless information and power transfer (SWIPT) [17], [18], spectrum sharing [19], cognitive radio [20], unmanned aerial vehicle (UAV) communication [21], millimeter wave [22], [23], and mobile edge…”
Intelligent Reflecting Surface: Practical Phase Shift Model and Beamforming Optimization (2019, background): “In future work, it is worth investigating such performance difference in more general IRS-aided wireless communication setups, such as multi-user systems [2], [4], OFDM-based system [17], physical layer security system [18], simultaneous wireless information and power transfer (SWIPT) systems [19], ”