Massive multiple-input and multiple-output systems combined with hybrid beamforming technique is a key approach to achieve high data rate and extended cell coverage in the fifth generation (5G) cellular networks . Specifically, the precoding for analog/digital hybrid beamforming technique is absolutely essential for millimeter-wave (mm-wave) frequency based transmission for 5G, simply because the technique reduces hardware complexity and energy consumption for high-frequency design. In order to prove the aforementioned advantages, the present paper will investigate the energy efficiency (EE) and optimization of low complexity hybrid precoding (EELCHP) algorithm to enable the reduction of radio frequency (RF) chains within the base station (BS). The proposed solution will also incorporate high-resolution phase shifters (HRPS) specifically for downlink multi-user mm-wave system. The intelligence within the EELCHP algorithm for hybrid beamforming is based on the fully complex zero-forcing (ZF) precoding mechanism that allowed the maximization of energy efficiency by reducing the RF chains, without affecting the potentially increasing number of antennas. In addition, maximum EE is possible by eliminating the nonlinear concave fractional issue based on the Lagrange duality method. During the simulation process of the proposed method, we further realized that hardware complexity and power consumption can be reduced by allowing the RF chains to select only one beam per switch within the beamforming solution. Furthermore, with the implementation of EELCHP algorithm, more energy is saved due to low complexity system by reducing the required RF chain.

大规模的多输入多输出系统与混合波束成形技术相结合是在第五代（5G）蜂窝网络中实现高数据速率和扩展小区覆盖范围的关键方法。特别是，对于5G基于毫米波（mm-wave）频率的传输，模拟/数字混合波束成形技术的预编码绝对必要，这仅仅是因为该技术降低了高频设计的硬件复杂性和能耗。为了证明上述优点，本文将研究能量效率（EE）和低复杂度混合预编码（EELCHP）算法的优化，以减少基站（BS）内的射频（RF）链。拟议的解决方案还将结合专门用于下行链路多用户毫米波系统的高分辨率移相器（HRPS）。EELCHP算法中用于混合波束成形的智能基于完全复杂的零强迫（ZF）预编码机制，该机制通过减少RF链实现了能量效率的最大化，而不会影响潜在增加的天线数量。另外，通过消除基于拉格朗日对偶方法的非线性凹分数问题，可以实现最大EE。在提出的方法的仿真过程中，我们进一步认识到，通过在波束成形解决方案中允许RF链在每个开关中仅选择一个波束，可以降低硬件复杂性和功耗。此外，随着EELCHP算法的实施，