密集分布式MIMO下行传输理论与方法研究

With the development of ultra-densification technique and cloud radio access network, mobile communication systems will evolve to ultra-dense distributed multiple input multiple output (MIMO) systems, featured with user-centric antenna scheduling and massive distributed MIMO transmission. Ultra-dense distributed MIMO has the advantages of distributed antenna systems (DASs) and massive MIMO. .In this project, we will study the downlink transmission theory and method of ultra-dense distributed MIMO. At first, we will deal with key link level problems, including multiuser precoding and channel estimation. Then we will analyze the spectral efficiency and energy efficiency, using large dimensional random matrix theory and statistical mechanics approach as the main tool. Based on these results, we will study the antenna scheduling algorithm and deployment policy. In the research, we will consider the large system asymptotic regime where both the density of antennas and the density of users approach infinity while keeping a fixed ratio. We will put emphasis on the study of channel hardening and macro diversity. The results of this project will provide the theoretic foundation and technique support for future mobile communications.

未来移动通信系统中，超密组网引入密集的天线节点，云接入使节点协作能力逐步增强。无线接入网络将演进成为密集分布式MIMO系统，形成以用户为中心的天线调度和大规模MIMO无线传输。密集分布式MIMO融合分布式天线和大规模MIMO的技术优势，但并非二者的简单叠加，存在很多具有挑战性的新问题。本项目拟针对密集分布式MIMO下行传输理论进行系统的研究。首先研究多用户预编码方法，探明复杂协作关系下提升传输效率的机理；其次研究信道估计方法，解决导频污染限制下的信道信息获取问题；然后应用高维随机矩阵等工具分析系统能量效率和频谱效率，揭示分密集布式MIMO的宏分集增益和“信道硬化”现象；最后，在链路分析基础上探索天线资源调度和配置方法。研究中，以天线和用户无限密集场景的极限分析作为主要方法，以大量天线微观性质相互平均产生的宏观特征作为理论分析突破口，力争形成比较完整的理论体系，并在某些点上获得漂亮的结果。

密集分布式MIMO无线通信理论是支撑未来移动通信发展的重要研究方向。本项目针对密集分布式MIMO系统下行传输技术开展研究。首先针对天线和用户数剧增造成的系统复杂性和导频污染问题，研究了链路传输中的预编码设计和导频调度方法。然后推导链路传输的频谱效率和能量效率，开展天线调度和配置方向的优化工作。最后研究了分布式MIMO下行SWIPT系统中的资源分配方法。经过四年的努力，在各研究方向上分别得到了有用的理论结果和/或有效的解决方案，发表期刊论文19篇，国际会议论文7篇；申请国家发明专利8件，获得国家发明专利授权6件，顺利完成了各项计划目标。