The performance of the hybrid beamforming system based on the full-connected structure is close to that of the full-digital one in millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) systems. However, due to the high complexity of circuit wiring in practical applications, it has been greatly restricted. This paper investigates the hybrid (analog/digital) beamforming design of a multiuser mmWave massive MIMO system with sub-connected structure. For this system, we focus on a sum-rate maximization probelm. Considering the joint design of the receiver, and transmitter, a two-stage design method is adopted. In the analog stage, the analog beamformer, and combiner are designed by the proposed piecewise dual joint iterative approximation (PDJIA) method, which not only can obtain closed-form solutions but also has linear property. Based on the criterion of avoiding the loss of information, the problem of digital beamforming is solved by exploiting the baseband piecewise successive approximation (BPSA) method, which can effectively increase the number of users served. Simulation results show that the proposed scheme outperforms the state-of-the art MIMO hybrid beamforming design schemes, and more accurately approximates to that of the full-digital system.

中文翻译：

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具有子连接结构的毫米波大规模多用户MIMO系统的双迭代混合波束成形设计

基于全连接结构的混合波束成形系统的性能接近毫米波（mmWave）大规模多输入多输出（MIMO）系统中的全数字波束成形系统。但是，由于电路布线在实际应用中的高度复杂性，受到了很大的限制。本文研究了具有子连接结构的多用户毫米波大规模 MIMO 系统的混合（模拟/数字）波束成形设计。对于这个系统，我们专注于和速率最大化问题。考虑到接收机和发射机的联合设计，采用两阶段设计方法。在模拟阶段，模拟波束形成器和组合器采用分段双联合迭代逼近（PDJIA）方法设计，不仅可以获得封闭形式的解，而且​​具有线性特性。基于避免信息丢失的准则，利用基带分段逐次逼近（BPSA）方法解决了数字波束赋形问题，可有效增加服务用户数。仿真结果表明，所提出的方案优于最先进的 MIMO 混合波束成形设计方案，更准确地接近全数字系统。