摘   要：在最新的世界移动通信大会上，各大移动通信业巨头争相推出了5G相关技术设备，这表明5G技术已经从理论变成了现实。随着5G时代的到来，日趋紧张的无线通信资源已经无法满足日益增长的用户需求，如何有效提高数据传输效率和提升数据传输可靠性成为了人们关注的话题。而多用户MIMO（Multiple Input Multiple Output）被认为是有效提高资源传输速率的重要方法之一。多用户MIMO利用发射端和接收端的多根天线获得空间分集增益和复用增益，以此提高系统容量和频谱利用率。

本课题主要是研究天线相关性对一定速率范围内的多用户MIMO系统性能的影响。从容量的角度来看，移动平台（MU）的天线相关性实际上是有益的。这个发现在实际应用中是有重要作用的，因为最小化MU的物理尺寸是非常必要的，但是它可能导致天线相关性。多输入多输出（MIMO）系统中的天线相关性有两个后果。首先，它减少了自由度;；因此对系统性能造成的损失在高速率（或功率）情况下最为显著。 第二，它增加波束成形的潜在增益; 因此对系统性能的增益在低速率（或功率）情况下最为显著。这两个相反的效应导致了具有和不具有天线相关性的系统的容量曲线之间的交叉点。在这点以下，系统容量因为相关性而增加了，在这点以上，则因相关性而减少了。 在传统的单用户MIMO系统中，交叉点在相对低的信息速率时产生，因此天线相关性通常被认为是不利因素。而在多用户MIMO系统中，上面提到的交叉点发生的速率随着MU数量的增加而提高，因此本论文对基于不同移动平台数量和一定速率的多用户MIMO系统的天线相关增益进行了仿真分析。

关键词：多用户MIMO；速率约束；移动平台；天线相关

Abstract：With the advent of the Internet plus era, limited wireless communication resources have been unable to meet the growing user needs, how to effectively improve the efficiency of data transmission and improve the reliability of data transmission has become a topic of concern, and multi-user MIMO (Multiple Input Multiple Output ) Is considered to be one of the important methods to improve the resource transmission rate effectively. Multi-user MIMO utilizes multiple antennas at the transmitter and receiver to obtain spatial persity gain and multiplexing gain to increase system capacity and spectrum utilization. The main purpose of this project is to study the effect of antenna correlation on the performance of multi-user MIMO systems in a certain rate range.From the capacity point of view, the antenna correlation of the mobile unit (MU) is actually beneficial. This finding has an important effect in practical applications because it is necessary to minimize the physical size of the MU, but it may lead to antenna correlation. There are two consequences for antenna correlation in multiple input multiple output (MIMO) systems. First, it reduces the degree of freedom; therefore the loss of system performance is most pronounced at high rates (or power). Second, it increases the potential gain of beamforming; therefore, the gain of system performance is most significant at low rate (or power).These two opposite effects result in intersections between the capacity curves with and without the antenna correlation.In this point, the correlation is advantageous for the system capacity, and at this point, it is disadvantageous. In conventional single-user MIMO systems, intersections are generated at relatively low information rates, so antenna correlation is often considered a disadvantage. In the multi-user MIMO system, the rate of the intersection mentioned above increases with the increase of the number of MUs. Therefore, the antenna-related gain of the multi-user MIMO system based on the number of different mobile units and the certain rate is simulated analysis.

Keywords: MU-MIMO;rate constraints; MUs;antenna correlation