Hybrid beamforming is a promising technique to reduce the complexity and cost of massive multiple-input multiple-output (MIMO) systems while providing high data rate. However, the hybrid precoder design is a challenging task requiring channel state information (CSI) feedback and solving a complex optimization problem. This paper proposes a novel RSSI-based unsupervised deep learning method to design the hybrid beamforming in massive MIMO systems. Furthermore, we propose i) a method to design the synchronization signal (SS) in initial access (IA); and ii) a method to design the codebook for the analog precoder. We also evaluate the system performance through a realistic channel model in various scenarios. We show that the proposed method not only greatly increases the spectral efficiency especially in frequency-division duplex (FDD) communication by using partial CSI feedback, but also has near-optimal sum-rate and outperforms other state-of-the-art full-CSI solutions.

本研究提出了一种基于 RSSI 的无监督深度学习方法来设计大规模 MIMO 系统中的混合波束成形，并通过适当的 CSI 反馈显著提高了频分双工 FDD 通信中的谱效率，并且提出了一种用于初始接入 IA 的同步信号 SS 以及用于模拟前置器的代码本的方法。

用于海量MIMO混合波束成形的无监督深度学习