近场效应空时信号设计关键技术研究

To meet the demand of low power consumption and ubiquitous access requirement for the next generation mobile communication systems, the multi-antenna techniques in the short-range scenarios have attracted significant attention. However, the near-field effects for the short-range scenarios have not been understood satisfactorily and applied in the actual system. This project aims to explore the theory of space-time signal design and detection, and solve the key technical problem for the short-range MIMO system..More specifically, it consists of the following three aspects: (1) analyze the relationship between the parameters introduced by near-field effects and space-time signal design for MIMO systems, and establish the mathematical model of received signal with near-field effects; (2) explore the space-time signal design metric with near-field effects , and obtain the degree of freedom for the spherical-wave model; (3) investigate the relationship between space-time signal design and transmission performance of the short-range MIMO system, and establish the method of transmit signal waveform optimization and the mechanism of optimal signal detection..The progress of signal processing for MIMO systems with near-field effects will reveal the interaction between the key characteristic parameters introduced by near-field effects and space-time signal design for MIMO systems. The research results can be applied to the future wireless communication systems such as next generation wireless network, wireless broadband access network, and the Internet of things, which are of great practical guiding significance.

新一代移动通信系统的低功耗和泛在接入需求，驱动近距离多天线通信场景所占的比例越来越大，然而近距离信道表现出的近场效应尚未深刻理解和有效应用。项目研究信道近场效应下的空时信号设计及检测理论，解决信道近场效应下多天线空时信号高效传输的关键技术问题。.项目研究无线信道近场效应特征参数与多天线空时信号设计的内在关系，建立包含信道近场特征的接收信号数学模型。探索近场效应特定环境下的空时信号设计准则，突破球面波维度的空间自由度理论。研究多天线近场信道环境下，空时信号设计与传输性能之间的关系，建立发射信号最佳波形设计方法与最优化的信号检测机制。.近场效应下多天线空时信号处理技术的进步，将会揭示近场信道关键特征参数与空时信号设计准则互作用的深层机理；研究成果，对新一代移动通信网、宽带无线接入网、无线物联网等无线通信系统的设计具有现实指导意义。

项目针对信道近场效应下的空时信号设计与检测技术，开展了如下4个方面的研究，共发表论文24篇，其中SCI检索论文18篇，申请专利3项，完成了全部研究计划。.(1).信道近场效应研究.针对空时信号设计需要，提取和分析近场效应的参数化特征，研究信道近场效应特征参数与空时信号设计的内在联系。.侧重研究点包括：分析完成信道近距离球面波前、角度扩展、天线阵元布局等关键参数的数学特征；分析了包含近场效应参数的信道空间自由度和容量。.(2).利用近场效应特征的空时信号设计.根据已经建立的近场效应下空时信号设计准则，研究主动利用信道近场效应特征的空时信号波形设计方案。.侧重研究点包括：对近距离多天线收发波形矩阵进行设计及优化，使之能够利用信道近场效应条件；开展了空时信号层间相关性编码研究，匹配信道的空间角度扩展特征；进行高频谱效率空时码设计，在信道近场效应下的频谱效率能够与其可实现的最大自由度和容量相比拟。.(3).近场效应下优化的接收机检测算法及天线布局.针对信道近场效应下的优化空时信号设计，研究低复杂度的优化接收检测算法及近距离天线布局。.侧重研究点包括：利用近场效应下空时码的结构设计特征，建立了低复杂度的优化接收检测算法；分析完成接收检测算法在近场效应下的误码率性能；建立了能够指导近距离通信网络天线位置摆放的理论模型。.(4).初步实验验证近场效应下的空时码通信能力.利用前期积累的可重构硬件实验平台，初步实验验证信道近场效应下的空时码有效性。.侧重研究点包括：利用可重构的硬件实验平台，搭建2×2通信链路，初步实验验证了所设计的适合近距离通信的空时码能力。