Passive beamforming design for intelligent reflecting surface assisted MIMO systems

Chenghao Feng, Wenqian Shen*, Xinyu Gao, Jianping An

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

Intelligent reflecting surfaces (IRSs) constitute passive devices, which are capable of adjusting the phase shifts of their reflected signals, and hence they are suitable for passive beamforming. In this paper, we conceive their design with the active beamforming action of multiple-input multiple- output (MIMO) systems used at the access points (APs) for improving the beamforming gain, where both the APs and users are equipped with multiple antennas. Firstly, we decouple the optimization problem and design the active beamforming for a given IRS configuration. Then we transform the optimization problem of the IRS-based passive beamforming design into a tractable non-convex quadratically constrained quadratic program (QCQP). For solving the transformed problem, we give an approximate solution based on the technique of widely used semidefinite relaxation (SDR). We also propose a low-complexity iterative solution. We further prove that it can converge to a locally optimal value. Finally, considering the practical scenario of discrete phase shifts at the IRS, we give the quantization design for IRS elements on basis of the two solutions. Our simulation results demonstrate the superiority of the proposed solutions over the relevant benchmarks.

Original languageEnglish
Article number9384496
Pages (from-to)18-28
Number of pages11
JournalChina Communications
Volume18
Issue number3
DOIs
Publication statusPublished - Mar 2021

Keywords

  • MIMO systems
  • intelligent reflecting surface
  • passive beamforming

Fingerprint

Dive into the research topics of 'Passive beamforming design for intelligent reflecting surface assisted MIMO systems'. Together they form a unique fingerprint.

Cite this