High power consumption is one of the main problems in the practical application of massive multi-user multi-input-multi-output (MU-MIMO) systems, and using 1-bit digital-to-analog converters (DACs) instead of high-resolution DACs is an effective way to reduce the power consumption of massive MU-MIMO systems. How to design efficient precoding schemes to improve the performance of 1-bit MU-MIMO systems has become a hot research field. This paper mainly studies the precoding problem of 1-bit DACs based on minimum mean squared error (MMSE). We first transform the non-convex constraints of the traditional optimization problem using binary equilibrium constraints. Then, to solve the transformed objective problem, we establish a framework based on the alternating direction method (ADM), use the fast projection gradient (FPG) method, and propose an alternating maximum minimum (AMM) algorithm to solve the optimization variables alternately. We have verified the convergence of the proposed algorithm and analyzed the accuracy of the proposed ADM framework and the computational complexity of the proposed algorithm in detail. In the simulation section, we analyze the uncoded bit error rate (BER) performance of the proposed algorithm in phase-shift keying (PSK) modulation and quadrature amplitude modulation (QAM) modes. The simulation results show that compared with existing advanced algorithms, the proposed algorithm can achieve performance advantages of about 1 dB and 2 dB in QPSK modulation mode and 16QAM modulation mode, respectively.

中文翻译：

---

基于二元平衡约束的 MU-MIMO 1 位 DAC 预编码：交替方向法

高功耗是大规模多用户多输入多输出（MU-MIMO）系统实际应用中的主要问题之一，并且使用1位数模转换器（DAC）代替高功耗分辨率 DAC 是降低大规模 MU-MIMO 系统功耗的有效方法。如何设计高效的预编码方案来提高1比特MU-MIMO系统的性能已成为研究的热点领域。本文主要研究基于最小均方误差（MMSE）的1位DAC的预编码问题。我们首先使用二元平衡约束来转换传统优化问题的非凸约束。然后，为了解决变换后的目标问题，我们建立了基于交替方向法（ADM）的框架，使用快速投影梯度（FPG）方法，并提出了交替最大最小（AMM）算法来交替求解优化变量。我们验证了所提出算法的收敛性，并详细分析了所提出ADM框架的准确性和所提出算法的计算复杂度。在仿真部分，我们分析了所提出算法在相移键控（PSK）调制和正交幅度调制（QAM）模式下的未编码误码率（BER）性能。仿真结果表明，与现有先进算法相比，该算法在QPSK调制模式和16QAM调制模式下分别能实现约1 dB和2 dB的性能优势。