Channel Hardening of IRS-Aided Multi-Antenna Systems: How Should IRSs Scale?

Bereyhi A, Asaad S, Ouyang C, Müller R, Schaefer RF, Vincent Poor H (2023)

Publication Type: Journal article

Publication year: 2023

Journal

IEEE Journal on Selected Areas in Communications Institute of Electrical and Electronics Engineers (IEEE)

Pages Range: 1-1

DOI: 10.1109/JSAC.2023.3288237

Abstract

It is widely believed that large IRS-aided MIMO settings maintain the fundamental features of massive MIMO systems. This work gives a rigorous proof that confirms this belief. We show that using a large passive IRS, the end-to-end MIMO channel between the transmitter and the receiver always hardens, even if the IRS elements are strongly correlated. For fading direct and reflection links between the transmitter and the receiver, our derivations demonstrate that for a large number of reflecting elements on the IRS, the capacity of the end-to-end channel is accurately approximated by a real-valued Gaussian random variable whose variance goes to zero as the number of IRS elements grows unboundedly large. The order of this drop depends on how the physical dimensions of the IRS grow. We derive this order explicitly. Numerical experiments show that the closed-form approximation very closely matches the histogram of the capacity term, even in practical scenarios. As a sample application of the results, we characterize the dimensional trade-off between the transmitter and the IRS. The result is intuitive: For a target performance, the larger the IRS is, the fewer transmit antennas are required.

Authors with CRIS profile

Ralf Müller Professur für Informationsübertragung

Involved external institutions

Beijing University of Posts and Telecommunications (BUPT) / 北京邮电大学 CN China (CN) York University CA Canada (CA) Princeton University US United States (USA) (US) University of Toronto CA Canada (CA) Technische Universität Dresden DE Germany (DE)

How to cite

APA:

Bereyhi, A., Asaad, S., Ouyang, C., Müller, R., Schaefer, R.F., & Vincent Poor, H. (2023). Channel Hardening of IRS-Aided Multi-Antenna Systems: How Should IRSs Scale? IEEE Journal on Selected Areas in Communications, 1-1. https://dx.doi.org/10.1109/JSAC.2023.3288237

MLA:

Bereyhi, Ali, et al. "Channel Hardening of IRS-Aided Multi-Antenna Systems: How Should IRSs Scale?" IEEE Journal on Selected Areas in Communications (2023): 1-1.

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