TY - JOUR
T1 - On the Mutual Information of Multi-RIS Assisted MIMO
T2 - From Operator-Valued Free Probability Aspect
AU - Zheng, Zhong
AU - Wang, Siqiang
AU - Fei, Zesong
AU - Sun, Zhi
AU - Yuan, Jinhong
N1 - Publisher Copyright:
© 1972-2012 IEEE.
PY - 2023/12/1
Y1 - 2023/12/1
N2 - The reconfigurable intelligent surface (RIS) is useful to effectively improve the coverage and data rate of end-to-end communications. In contrast to the well-studied coverage-extension use case, in this paper, multiple RIS panels are introduced, aiming to enhance the data rate of multi-input multi-output (MIMO) channels in presence of insufficient scattering. Specifically, via the operator-valued free probability theory, the asymptotic mutual information of the large-dimensional RIS-assisted MIMO channel is obtained under the Rician fading with Weichselberger's correlation structure, in presence of both the direct and the reflected links. Although the mutual information of Rician MIMO channels scales linearly as the number of antennas and the signal-to-noise ratio (SNR) in decibels, numerical results show that it requires sufficiently large SNR, proportional to the Rician factor, in order to obtain the theoretically guaranteed linear improvement. This paper shows that the proposed multi-RIS deployment is especially effective to improve the mutual information of MIMO channels under the large Rician factor conditions. When the reflected links have similar arriving and departing angles across the RIS panels, a small number of RIS panels are sufficient to harness the spatial degree of freedom of the multi-RIS assisted MIMO channels.
AB - The reconfigurable intelligent surface (RIS) is useful to effectively improve the coverage and data rate of end-to-end communications. In contrast to the well-studied coverage-extension use case, in this paper, multiple RIS panels are introduced, aiming to enhance the data rate of multi-input multi-output (MIMO) channels in presence of insufficient scattering. Specifically, via the operator-valued free probability theory, the asymptotic mutual information of the large-dimensional RIS-assisted MIMO channel is obtained under the Rician fading with Weichselberger's correlation structure, in presence of both the direct and the reflected links. Although the mutual information of Rician MIMO channels scales linearly as the number of antennas and the signal-to-noise ratio (SNR) in decibels, numerical results show that it requires sufficiently large SNR, proportional to the Rician factor, in order to obtain the theoretically guaranteed linear improvement. This paper shows that the proposed multi-RIS deployment is especially effective to improve the mutual information of MIMO channels under the large Rician factor conditions. When the reflected links have similar arriving and departing angles across the RIS panels, a small number of RIS panels are sufficient to harness the spatial degree of freedom of the multi-RIS assisted MIMO channels.
KW - MIMO
KW - Reconfigurable intelligent surface
KW - Rician channel
KW - mutual information
KW - operator-valued free probability
UR - http://www.scopus.com/inward/record.url?scp=85181094053&partnerID=8YFLogxK
U2 - 10.1109/TCOMM.2023.3317281
DO - 10.1109/TCOMM.2023.3317281
M3 - Article
AN - SCOPUS:85181094053
SN - 1558-0857
VL - 71
SP - 6952
EP - 6966
JO - IEEE Transactions on Communications
JF - IEEE Transactions on Communications
IS - 12
ER -