TY - JOUR
T1 - Double-RIS Aided Multi-User MIMO Communications
T2 - Common Reflection Pattern and Joint Beamforming Design
AU - Zhang, Pingping
AU - Gong, Shiqi
AU - Ma, Shaodan
N1 - Publisher Copyright:
© 1967-2012 IEEE.
PY - 2024/3/1
Y1 - 2024/3/1
N2 - Reconfigurable intelligent surface (RIS) has entered the public consciousness as a promising technology for enhancing the performance of future wireless communication systems by dynamically constructing the wireless channels. In this letter, we study a double-RIS aided downlink multi-user multiple-input multiple-output (MIMO) communication system. We investigate the mean-square-error (MSE) minimization problem by jointly optimizing the active transmit beamforming, the receive equalizer and the passive beamforming at each RIS. Different from prior works, for the sake of reducing both communication overhead and signal processing complexity, we assume that the two RISs utilize the common reflection pattern. Under this assumption, the coupling of the variables becomes tighter, thereby making the optimization problem more challenging to solve. To effectively address this issue, we propose a majorization-minimization (MM) based alternating optimization (AO) algorithm. Numerical results show that in high signal-to-noise ratio (SNR) region, the double-RIS with common reflection pattern can achieve nearly the same performance as that with separate reflection pattern whereas the complexity is only half of the latter. Thus, our proposed design enables an effective tradeoff between the performance and the implementation complexity of the considered system.
AB - Reconfigurable intelligent surface (RIS) has entered the public consciousness as a promising technology for enhancing the performance of future wireless communication systems by dynamically constructing the wireless channels. In this letter, we study a double-RIS aided downlink multi-user multiple-input multiple-output (MIMO) communication system. We investigate the mean-square-error (MSE) minimization problem by jointly optimizing the active transmit beamforming, the receive equalizer and the passive beamforming at each RIS. Different from prior works, for the sake of reducing both communication overhead and signal processing complexity, we assume that the two RISs utilize the common reflection pattern. Under this assumption, the coupling of the variables becomes tighter, thereby making the optimization problem more challenging to solve. To effectively address this issue, we propose a majorization-minimization (MM) based alternating optimization (AO) algorithm. Numerical results show that in high signal-to-noise ratio (SNR) region, the double-RIS with common reflection pattern can achieve nearly the same performance as that with separate reflection pattern whereas the complexity is only half of the latter. Thus, our proposed design enables an effective tradeoff between the performance and the implementation complexity of the considered system.
KW - Common reflection pattern
KW - MSE
KW - double-RIS
KW - multi-user MIMO system
UR - http://www.scopus.com/inward/record.url?scp=85174854353&partnerID=8YFLogxK
U2 - 10.1109/TVT.2023.3324504
DO - 10.1109/TVT.2023.3324504
M3 - Article
AN - SCOPUS:85174854353
SN - 0018-9545
VL - 73
SP - 4418
EP - 4423
JO - IEEE Transactions on Vehicular Technology
JF - IEEE Transactions on Vehicular Technology
IS - 3
ER -