毫米波通信中基于非完美信道状态信息的鲁棒混合波束成形技术研究

Millimeter wave (mmWave) communications can offer rich spectrum resources, which makes it a key enabling technology in the next generation mobile communication systems. However, the shorter wavelength of mmWave signals leads to the low penetration ability and severe propagation path loss. The digital analog hybrid beamforming technology is the key issue in the field of mmWave communications, which can improve the transmission quality and fulfill the limitations of equipment space, power consumption and hardware cost. Most existing researches are based on the perfect channel state information. These schemes cannot handle the impact of channel uncertainty, which makes them difficult to be implemented in practice. The proposed project aims at designing robust hybrid beamforming schemes under different channel error models and antenna structures. The main contributions are: 1) the complete framework and design scheme of the robust hybrid beamforming optimization problem are proposed, which cover the single-user as well as the multi-user mmWave communication systems; 2) the interference in multi-user networks are suppressed by the use of the whole large-scale antenna array in mmWave equipments; 3) different optimization algorithms are utilized to design beamforming schemes in mmWave systems. Based on these algorithms, improved methods with lower computational complexity are proposed to promote the implementation of mmWave technology in the next generation mobile communication systems.

毫米波通信能提供丰富的频谱资源，是下一代移动通信系统的关键技术之一。然而较短的波长导致毫米波信号穿透力差，传输路径损耗严重。为了改善传输质量，同时满足设备空间、功耗与成本的要求，数字模拟混合波束成形技术成为毫米波研究领域的重点问题。现有绝大多数相关研究都基于完美信道状态信息来进行设计，其方案无法处理信道不确定性带来的影响，在实际系统中难以应用。本项目旨在针对不同信道误差模型与天线结构，设计具有鲁棒性的混合波束成形方案，主要贡献有：1) 构建鲁棒波束成形优化问题的完整框架与设计流程，该框架与流程可应用于单用户及多用户毫米波通信系统；2) 充分利用毫米波设备大规模天线阵的优势，完成多用户网络中的干扰抑制；3) 运用多种优化算法求解各毫米波系统优化问题，并在此基础上，提出降低计算复杂度的改进方案，促进毫米波技术在下一代移动通信系统中的应用。

作为下一代移动通信系统的关键技术之一，毫米波通信是目前相关领域的热点研究对象。如何在满足设备空间、功耗与成本要求的前提下，利用波束成形技术增强毫米波通信的传输质量，是该领域亟待解决的问题，也是本项目的主要研究内容。本项目主要取得了以下研究成果：1) 针对适用于毫米波信道的估计技术，提出了对应的信道估计误差模型，该模型可推广至多种毫米波通信系统中，是相关鲁棒混合波束成形设计的基础；2) 基于毫米波信道估计误差模型，构建了鲁棒混合波束成形优化问题的完整框架与设计流程，并基于系统特性提出了低复杂度的优化方案；3) 将毫米波通信与全双工技术相结合，通过混合波束成形设计有效抑制了自干扰，实现了系统时频资源的充分利用。本研究的科学意义在于：通过鲁棒混合波束成形技术，为毫米波通信在下一代移动通信系统中的应用打下了坚实的基础。