TY - JOUR
T1 - Passive beamforming design for intelligent reflecting surface assisted MIMO systems
AU - Feng, Chenghao
AU - Shen, Wenqian
AU - Gao, Xinyu
AU - An, Jianping
N1 - Publisher Copyright:
© 2013 China Institute of Communications.
PY - 2021/3
Y1 - 2021/3
N2 - 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.
AB - 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.
KW - MIMO systems
KW - intelligent reflecting surface
KW - passive beamforming
UR - http://www.scopus.com/inward/record.url?scp=85103326605&partnerID=8YFLogxK
U2 - 10.23919/JCC.2021.03.002
DO - 10.23919/JCC.2021.03.002
M3 - Article
AN - SCOPUS:85103326605
SN - 1673-5447
VL - 18
SP - 18
EP - 28
JO - China Communications
JF - China Communications
IS - 3
M1 - 9384496
ER -