Hybrid Receiver Design for Massive MIMO-OFDM with Low-Resolution ADCs and Oversampling

TL;DR

This paper proposes a hybrid receiver design for massive MIMO-OFDM systems with low-resolution ADCs and oversampling, optimizing spectral efficiency and energy efficiency through joint analog-digital combiner design considering quantization distortion.

Contribution

It introduces a closed-form approximation of quantization distortion covariance and a novel iterative design algorithm for hybrid combiners under low-resolution ADC constraints.

Findings

The proposed algorithm outperforms benchmarks in spectral efficiency.

Hybrid receiver shows resilience to beam squint effects.

Design achieves higher energy efficiency than fully digital systems.

Abstract

Low-resolution analog-to-digital converters (ADCs) and hybrid beamforming have emerged as efficient solutions to reduce power consumption with satisfactory spectral efficiency (SE) in massive multiple-input multiple-output (MIMO) systems. In this paper, we investigate the performance of a hybrid receiver in massive MIMO orthogonal frequency-division multiplexing (OFDM) uplink systems with low-resolution ADCs and oversampling. Considering both the temporal and spatial correlation of the quantization distortion (QD), we derive a closed-form approximation of the frequency-domain QD covariance matrix, which facilitates the evaluation of the system's SE. Then we jointly design the analog and digital combiners of the hybrid receiver to maximize the SE. The formulated problem is challenging due to the constant-modulus constraint of the analog combiner and its coupling with the digital one. To overcome these challenges, we transform the objective function into an equivalent but more tractable form and then iteratively update the analog and digital combiners. Numerical simulations verify the superiority of the proposed algorithm over the considered benchmarks and show the resilience of the hybrid receiver to beam squint with low-resolution ADCs. Furthermore, the proposed hybrid receiver design with oversampling can achieve significantly higher energy efficiency compared with the fully digital one.