  Low-resolution analog-to-digital converters (ADCs) have emerged as an
efficient solution for massive multiple-input multiple-output (MIMO) systems to
reap high data rates with reasonable power consumption and hardware complexity.
In this paper, we analyze the performance of oversampling in uplink massive
MIMO orthogonal frequency-division multiplexing (MIMO-OFDM) systems with
low-resolution ADCs. Considering both the temporal and spatial correlation of
the quantization distortion, we derive an approximate closed-form expression of
an achievable sum rate, which reveals how the oversampling ratio (OSR), the ADC
resolution, and the signal-to-noise ratio (SNR) jointly affect the system
performance. In particular, we demonstrate that oversampling can effectively
improve the sum rate by mitigating the impact of the quantization distortion,
especially at high SNR and with very low ADC resolution. Furthermore, we show
that the considered low-resolution massive MIMO-OFDM system can achieve the
same performance as the unquantized one when both the SNR and the OSR are
sufficiently high. Numerical simulations confirm our analysis.
