Performance Analysis on RIS-Aided Wideband Massive MIMO OFDM Systems with Low-Resolution ADCs

TL;DR

This paper analyzes the performance of RIS-assisted wideband massive MIMO-OFDM systems with low-resolution ADCs, deriving achievable rate expressions, analyzing asymptotic behavior, and proposing an algorithm for optimizing RIS phase shifts.

Contribution

It provides a comprehensive performance analysis including closed-form rate expressions, asymptotic analysis, power scaling laws, and a novel phase shift optimization algorithm for RIS-aided systems.

Findings

Achievable rate expressions derived for the system.

Asymptotic performance analyzed as antennas and RIS elements grow large.

Power scaling laws reveal energy-saving potential.

Abstract

This paper investigates a reconfigurable intelligent surface (RIS)-aided wideband massive multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with low-resolution analog-to-digital converters (ADCs). Frequency-selective Rician fading channels are considered, and the OFDM data transmission process is presented in time domain. This paper derives the closed-form approximate expression of the uplink achievable rate, based on which the asymptotic system performance is analyzed when the number of the antennas at the base station and the number of reflecting elements at the RIS grow to infinity. Besides, the power scaling laws of the considered system are revealed to provide energy-saving insights. Furthermore, this paper proposes a gradient ascent-based algorithm to design the phase shifts of the RIS for maximizing the minimum user rate. Finally, numerical results are presented to verify the correctness of analytical conclusions and draw insights.