多小区多用户MIMO系统中干扰对齐算法研究

In the next generation of the wireless network, the multi-antennas ( multiple input multiple output, MIMO)technology will be widely adopted，and multi-user MIMO (MU-MIMO) technology with the spatial multiplexing and the multi-user diversity gain is paid more attention for higher spectrum efficiecy, but it is easier interferenced by the multi-antennas system in the other cell, especially the cell edge users, and the available technologies can not slove the problem well. The interference alignment technology (IA) solved the above problem and changed the traditional theory about the network which is limmited by the interference. However, the IA technology in the multi-user MIMO of the multi-cell system is not perfect, there remains a lot of the basic theory and key problems to be solved. According to the system characteristics and combined with the generalized principle of the IA, this project focuses on the IA of the multi-user MIMO of the multi-cell system. Based on the related perspective between the design of the system configuration and the structure of the the closed form solution, and excavate the new theory about the optimum interference alignment based on the minimum system configuration for the general universal scenarios, open up the new idea and breakthrough the structure for the compression ratio and the closed form solution of the IA, complete the theoretical system of the system and enrich its implementation. The research will improve the system spatial resources efficiency, and suppress the inter-cell interference, which leads to the improvmen of the system capacity and spectrum utilization.

在下一代无线网络中将广泛采用多天线（MIMO）技术，利用空间复用和具有多用户分集增益的多用户MIMO(MU-MIMO)技术以提供更高的频谱效率而备受关注,但更易受小区间多天线系统的同频干扰，特别是小区边缘用户，现有的干扰抑制技术已不能很好地解决该问题。干扰对齐技术（IA）有效地解决了上述问题，颠覆了通信网络干扰受限的传统理论，但目前对多小区多用户MIMO场景下IA技术的研究还不完善，还有很多基础性和关键性的问题有待解决。本项目针对该系统中IA技术展开研究，根据系统特性，结合IA的一般化原理，抓住系统配置设计和闭式解构造之间紧密关联的视角，在普适场景下挖掘基于最小系统配置实现最优IA的新理论方法，开拓实现IA的新思路，突破干扰对齐压缩比及闭式解构造的难题，完善该系统下干扰对齐的理论体系，丰富其实现方法。研究成果将有利于提高系统空间资源效率、抑制小区间干扰，提升系统容量和频谱利用率。

作为解决蜂窝网络干扰的有效手段，干扰对齐技术颠覆了通信网络干扰受限的传统理论，但目前对具有高频谱效率的多小区多用户 MIMO 场景下研究有待完善，包括自由度理论限和高效实用干扰对齐实现方法等各个方面。本项目主要研究了该场景下系统配置设计和干扰对齐闭式解构造方法研究等主要问题和解决方法。首先通过对收发节点进行配对分组、优化传递顺序，构思全新的干扰对齐闭式解等，提出了三种新型的反馈拓扑结构，克服缺陷的同时降低CSI开销；其次对异构网络中同级干扰与跨级干扰，建立了线性干扰对齐的广义可行性条件，推导出可达自由度的最少总天线资源用量，设计了分级干扰对齐闭式解方案；然后针对三小区多用户MIMO场景，提出多用户天线循环分组干扰对齐构造方案，以最紧逼近系统的自由度上限，在部分情况下达到了自由度上限，又通过灵活调节基站和用户两侧的天线需求数目，实现天线资源用量与自由度增益的有效折中；此外针对分布式干扰对齐场景和机会干扰对齐场景，提出多种低复杂度的干扰对齐实施算法；最后，研究了两小区两跳MIMO干扰信道的自由度下界，提出一种仅需局部CSI的中继传输协议，在达到2/3个归一化自由度时可明显降低解码复杂度，且从理论上证明了可达归一化自由度为1。研究成果将有利于提高系统空间资源效率、抑制小区间干扰，提升系统容量和频谱利用率。