大规模MIMO系统非相干信号重构与信息提取方法研究

Massive MIMO is an important technology in the future mobile communication systems, and has attracted much attention because of their ability to significantly increase capacity and enhance communication coverage. Aiming at the researches of physical layer transmission theory and technology, it is of great practical significance and scientific value to promote the application of massive MIMO systems to engineering applications. Although the traditional data-assisted coherent transmission method can be applied to massive MIMO systems, it still faces the challenges of large signaling overhead, high processing complexity, and low transmission efficiency. This topic focuses on the basic scientific problem of "high-efficiency physical-layer transmission strategy in massive MIMO systems". This project will develop non-coherent signal transmission, reconstruction and information extraction methods based on the statistical channel characteristics. Firstly, the non-coherent space-time transmission method is studied in the quasi-static channel environments. Secondly, the non-coherent signal reconstruction method is studied by considering the eigenvalue decomposition and optimization algorithm in the high-speed fast time-varying channel environments. Finally, the non-coherent signal reconstruction and key communication information extraction from large-dimensional received data is discussed in the non-cooperative communication scenario. The research of this subject enriches and perfects the theoretical basis of large-scale MIMO physical layer transmission, and provides theoretical guidance for the system in actual deployment and application.

大规模MIMO系统是未来移动通信中的一项重要技术，因其能够显著提升容量和增强覆盖等优势而备受关注。针对物理层传输理论和技术的研究，是推动大规模MIMO系统走向工程应用的关键，具有重大的现实意义和科学价值。传统的基于数据辅助的相干传输方法在应用于大规模MIMO系统时，面临着信令开销大、处理复杂度高、传输效率低等挑战。本课题围绕“在通信物理层解决大规模MIMO系统的高效传输”这一基本科学问题，拟开展基于大规模MIMO系统信道统计特性的非相干信号传输、重构与信息提取方法研究。首先，研究准静态信道环境下空时域联合处理的非相干传输方法；然后，考虑在高移动的快时变信道环境中，研究基于特征分解与优化算法求解的非相干信号重构方法；最后，扩展至非合作通信场景，研究从大维接收数据中进行信号重构与关键信息提取的方法。本课题的研究丰富和完善大规模MIMO物理层传输的理论基础，为系统在实际部署和应用中提供理论指导。

聚焦大规模天线系统中多用户与基站的无线通信传输，以经典信号处理、常规多天线传输方式为基础，研究了大规模天线系统下的物理层上行传输处理问题，形成了通信信号产生、处理以及鲁棒传输的方法和策略。主要研究内容和成果包括：（1）在非相干传输模型、大规模天线空时域特性分析、非相干信号检测、大规模天线空时域频偏同步及抗频带干扰等方面进行了深入研究，通过理论分析、数学建模、算法优化和仿真验证，表明了所提方案和算法的有效性。（2）建立了多用户同时传输的基带信号传输模型，并构建了非相干信号检测的数学问题，并通过理论分析和等价转换，将原非凸的NP问题转化为两个子问题的求解，即通过半定松弛优化问题获得重构信号的参考信号，而后通过少量的训练信息获得相位旋转值，从而获取最终的信号重构结果。（3）考虑到实际通信系统传输过程中存在的频偏以及干扰问题，提出了一种基于恒包络零自相关（CAZAC）序列的低复杂度抗频偏同步算法，实现精确稳定的定时同步，同时获得更准确的频偏估计；（4）提出了一种基于前向连续方差去除（FCVE）的干扰检测算法和基于频率分集的干扰抑制算法，通过该组合策略大幅提高了部分频带干扰条件下的通信性能。课题的研究能够丰富大规模天线多用户MIMO系统的物理层传输理论，为实际的物理层方案工程实现提供理论支撑。