A Low-Complexity Precoding Scheme for Downlink Massive MU-MIMO Systems with Low-Resolution DACs

In this paper, we investigate the problem of downlink precoding for the narrowband massive multi-user multiple-input multiple-output (MU-MIMO) system with low-resolution digital-to-analog converters (DACs). We introduce a low-complexity precoding scheme based on the alternating direction method of multipliers (ADMM) framework in this work. An efficient gradient descent (GD) algorithm with adaptive step-size determination mechanism (ASGD) is proposed to alleviate the computational complexity bottleneck of the inherent matrix inversion. Numerical results demonstrate that the ASGD precoder achieves an attractive trade-off between the performance and computational complexity compared with other counterparts.