Analog/digital hybrid beamforming architectures with large-scale antenna arrays have been widely considered in millimeter wave (mmWave) communication systems because they can address the tradeoff between performance and hardware efficiency compared with traditional fully-digital beamforming. Most of the prior work on hybrid beamforming focused on fully-connected architecture or partially-connected scheme with fixed-subarrays, in which the analog beamformers are usually realized by infinite-resolution phase shifters (PSs). In this paper, we introduce a novel hybrid beamforming architecture with dynamic subarrays and hardware-efficient low-resolution PSs for mmWave multiuser multiple-input single-output (MU-MISO) systems. By dynamically connecting each RF chain to a non-overlap subarray via a switch network and PSs, we can exploit multiple-antenna and multiuser diversities to mitigate the performance loss due to the use of practical low-resolution PSs. An iterative hybrid beamformer design algorithm is first proposed based on fractional programming (FP), aiming at maximizing the sum-rate performance of the MU-MISO system. In an effort to reduce the complexity, we also present a simple heuristic hybrid beamformer design algorithm for the dynamic subarray scheme. Extensive simulation results demonstrate the advantages of the proposed hybrid beamforming architecture with dynamic subarrays and low-resolution PSs compared to existing fixed-subarray schemes.

中文翻译：

---

用于毫米波 MU-MISO 系统的具有动态子阵列和低分辨率 PS 的混合波束成形

具有大规模天线阵列的模拟/数字混合波束成形架构已在毫米波 (mmWave) 通信系统中得到广泛考虑，因为与传统的全数字波束成形相比，它们可以解决性能和硬件效率之间的权衡问题。大多数先前关于混合波束形成的工作都集中在具有固定子阵列的全连接架构或部分连接方案上，其中模拟波束形成器通常由无限分辨率移相器 (PS) 实现。在本文中，我们为毫米波多用户多输入单输出 (MU-MISO) 系统介绍了一种具有动态子阵列和硬件高效低分辨率 PS 的新型混合波束成形架构。通过交换网络和 PS 将每个 RF 链动态连接到非重叠子阵列，我们可以利用多天线和多用户多样性来减轻由于使用实用的低分辨率 PS 而造成的性能损失。首次提出了一种基于分数规划（FP）的迭代混合波束形成器设计算法，旨在最大化 MU-MISO 系统的总速率性能。为了降低复杂性，我们还为动态子阵列方案提出了一种简单的启发式混合波束形成器设计算法。广泛的仿真结果证明了与现有固定子阵列方案相比，所提出的具有动态子阵列和低分辨率 PS 的混合波束形成架构的优势。旨在最大化 MU-MISO 系统的总速率性能。为了降低复杂性，我们还为动态子阵列方案提出了一种简单的启发式混合波束形成器设计算法。广泛的仿真结果证明了与现有固定子阵列方案相比，所提出的具有动态子阵列和低分辨率 PS 的混合波束形成架构的优势。旨在最大化 MU-MISO 系统的总速率性能。为了降低复杂性，我们还为动态子阵列方案提出了一种简单的启发式混合波束形成器设计算法。广泛的仿真结果证明了与现有固定子阵列方案相比，所提出的具有动态子阵列和低分辨率 PS 的混合波束形成架构的优势。