多小区MIMO广播信道干扰对齐技术研究

发布时间：2018-08-16 11:16

【摘要】：随着无线通信的快速发展,日益增长的通信的需求与稀缺的频谱资源之间的矛盾凸显,而其中多输入多输出(Multiple Input and Multiple Input,MIMO)系统由于其可以在不需要增加带宽的情况下大幅度增加系统的吞吐量受到许多瞩目。MIMO技术利用多根发射天线和多根接收天线所提供的空间自由度可以有效提升无线通信的频谱效率。然而在多小区MIMO系统中存在天线间干扰、用户间干扰、小区间干扰等多种干扰问题严重影响了MIMO技术的使用。因此多小区MIMO系统的干扰管理问题已经成为了现代无线通信系统面临的一个关键问题。到目前为止,已经有多种干扰管理技术被提了出来,而其中,干扰对齐(Interference Alignment,IA)技术被认为是干扰管理的一个重大突破。干扰对齐是通过压缩干扰信号所占的信号维度,为期望信号提供更多的无干扰信号维度进行数据传输。这项技术能够使得多小区MIMO系统的自由度得到很大提升,因此研究多小区MIMO系统下的IA技术是具有很重要的意义的。然而对于现有的多小区MIMO广播信道下干扰对齐技术的研究,主要针对对称系统模型,也即各个小区的用户数是相等的,每个用户的数据流也是相等的,还有每个基站和用户的天线数也分别是相等的。在这样的系统模型下,通过干扰对齐技术,研究系统能达到自由度。而对于非对称多小区MIMO广播信道模型下系统所能达到的自由度相关的研究结论却较少。针对这一背景,本文提出了一种适用于非对称MIMO多小区广播信道下的广义分组干扰对齐算法。通过联合设计一个小区所有用户接收端的信号处理矩阵,对齐来自非本小区基站的小区间干扰信号,然后通过设计基站的发射预编码矩阵,使得发送的期望信号在接收端与干扰信号是正交的,这样用户就可以无干扰的解码期望信号。此外本文还引用了关于图论的一些结论分析了所提出的广义分组干扰对齐算法在非对称MIMO多小区广播信道模型下的可行性,以及推导了本文所提出的广义分组干扰对齐算法所能达到的自由度,仿真验证表明,本文所提出的广义分组干扰对齐算法,可以达到比已有干扰对齐算法更高的自由度。
[Abstract]:With the rapid development of wireless communication, the contradiction between the increasing demand for communication and the scarce spectrum resources is highlighted. Among them, multiple input multiple output (MIMO) systems have been proposed by many researchers using multiple transmit antennas and multiple receiving antennas because of their ability to significantly increase the throughput of the system without increasing the bandwidth. The spatial degree of freedom can effectively improve the spectrum efficiency of wireless communication. However, interantenna interference, inter-user interference and inter-cell interference exist in multi-cell MIMO systems, which seriously affect the use of MIMO technology. Therefore, interference management in multi-cell MIMO systems has become a key problem in modern wireless communication systems. Up to now, a variety of interference management techniques have been proposed, among which, Interference alignment (IA) technology is considered as a major breakthrough in interference management. Interference alignment is by compressing the signal dimension occupied by the interference signal to provide more non-interference signal dimensions for the desired signal for data transmission. This technique can greatly improve the degree of freedom of multi-cell MIMO system, so it is of great significance to study IA technology in multi-cell MIMO system. However, for the existing multi-cell MIMO broadcast channel interference alignment technology, mainly aimed at the symmetric system model, that is, the number of users in each cell is equal, and the data flow of each user is also equal. The number of antennas for each base station and user is also equal. In this system model, the system can achieve degree of freedom by interference alignment technology. However, there are few researches on the degree of freedom correlation under the asymmetric multi-cell MIMO broadcast channel model. In this paper, a generalized packet interference alignment algorithm for asymmetric MIMO multi-cell broadcast channels is proposed. By jointly designing a signal processing matrix for all users of the cell, the interference signals from the non-cell base station are aligned, and then the transmission precoding matrix of the base station is designed. The transmitted desired signal is orthogonal to the interference signal at the receiver so that the user can decode the desired signal without interference. In addition, some conclusions about graph theory are cited to analyze the feasibility of the proposed generalized packet interference alignment algorithm under the asymmetric MIMO multi-cell broadcast channel model. And the degree of freedom of the generalized packet interference alignment algorithm proposed in this paper is deduced. The simulation results show that the proposed generalized packet interference alignment algorithm can achieve higher degrees of freedom than the existing interference alignment algorithm.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

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