中国邮电高校学报(英文版) ›› 2016, Vol. 23 ›› Issue (6): 53-59.doi: 10.1016/S1005-8885(16)60070-5

• Wireless • 上一篇    下一篇

Gram-Schmidt based hybrid beamforming for mmWave MIMO systems

李晓辉1,林英超2,孟梅梅2,黑永强2   

  1. 1. 陕西省 西安电子科技大学
    2. 陕西省 西安电子科技大学综合业务网国家重点实验室
  • 收稿日期:2016-08-15 修回日期:2016-12-19 出版日期:2016-12-31 发布日期:2016-12-30
  • 通讯作者: 李晓辉 E-mail:xhli@mail.xidian.edu.cn
  • 基金资助:
    中国国家自然科学基金;国家863计划项目;国家111计划项目

Gram-Schmidt based hybrid beamforming for mmWave MIMO systems

  • Received:2016-08-15 Revised:2016-12-19 Online:2016-12-31 Published:2016-12-30
  • Contact: Xiao-Hui LI E-mail:xhli@mail.xidian.edu.cn
  • Supported by:
    National Natural Science Foundation of China;State 863 Project;State 111 Project

摘要: Due to the high cost and power consumption of the radio frequency (RF) chains, it is difficult to implement the full digital beamforming in millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems. Fortunately, the hybrid beamforming (HBF) is proposed to overcome these limitations by splitting the beamforming process between the analog and digital domains. In recent works, most HBF schemes improve the spectral efficiency based on greedy algorithms. However, the iterative process in greedy algorithms leads to high computational complexity. In this paper, a new method is proposed to achieve a reasonable compromise between complexity and performance. The novel algorithm utilizes the low-complexity Gram-Schmidt method to orthogonalize the candidate vectors. With the orthogonal candidate matrix, the slow greedy algorithm is avoided. Thus, the RF vectors are found simultaneously without any iteration. Additionally, the phase extraction is applied to satisfy the element-wise constant-magnitude constraint on the RF matrix. Simulation results demonstrate that the new HBF algorithm can make substantial improvements in complexity while maintaining good performance.

关键词: MIMO, hybrid beamforming, mmWave

Abstract: Due to the high cost and power consumption of the radio frequency (RF) chains, it is difficult to implement the full digital beamforming in millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems. Fortunately, the hybrid beamforming (HBF) is proposed to overcome these limitations by splitting the beamforming process between the analog and digital domains. In recent works, most HBF schemes improve the spectral efficiency based on greedy algorithms. However, the iterative process in greedy algorithms leads to high computational complexity. In this paper, a new method is proposed to achieve a reasonable compromise between complexity and performance. The novel algorithm utilizes the low-complexity Gram-Schmidt method to orthogonalize the candidate vectors. With the orthogonal candidate matrix, the slow greedy algorithm is avoided. Thus, the RF vectors are found simultaneously without any iteration. Additionally, the phase extraction is applied to satisfy the element-wise constant-magnitude constraint on the RF matrix. Simulation results demonstrate that the new HBF algorithm can make substantial improvements in complexity while maintaining good performance.

Key words: MIMO, hybrid beamforming, mmWave