下一代移动通信系统中大规模MIMO技术研究

发布时间：2018-03-28 17:36

本文选题：大规模MIMO　切入点：单位预编码　出处：《华侨大学》2014年硕士论文

【摘要】：随着用户需求的不断提高，高速率、高质量的通信系统是新一代移动通信技术的研究目标。以多输入多输出（Multiple Input Multiple Output, MIMO）为代表的多天线技术是目前公认的实现上述目标的最佳途径。然而在实际系统中，由于严重的小区间干扰和更高的数据传输要求，人们的研究焦点开始转向大规模MIMO技术，即在基站端采用大规模天线阵列（天线数超过十根，甚至上百根），且在同一时频资源内服务多个用户的多天线技术。与传统MIMO技术相比，该技术不仅可以显著提高系统频谱效率、改善通信质量，而且可以有效降低干扰消除的复杂度及基站发送功率。本文研究了大规模MIMO技术的频谱效率、能量效率，及其应用于异构网络时的系统性能。首先，运用随机矩阵理论，分别研究了大规模MIMO技术在单小区、多小区下行链路系统中，，当天线数趋于无穷大时，最大比传输（MRT）和迫零（ZF）单位预编码的极限性能，以及系统频谱效率的闭合表达式。其次，通过理论推导和MATLAB仿真，分析了两种预编码能量效率与天线数及发送功率的关系。最后，通过对比三种不同双工方式，给出大规模MIMO技术应用于异构网络时的性能分析。研究结果表明：（1）在基站已知完全信道状态信息（CSI）的条件下，当基站发送功率减小到单天线基站的1M时，随着基站天线数M的无限增加，系统频谱效率趋于恒定，并且MRT单位预编码的极限表达式与ZF单位预编码相同。因此基站可以采用简单的MRT预处理来消除用户间、小区间干扰以及快衰落影响。（2）当基站已知有限CSI时，小区间干扰因受CSI估计的影响不能完全消除，但随着发送功率的降低，系统将由干扰受限转变为噪声受限。（3）系统能量效率随天线数的增加逐渐提高，而随发送功率的增加逐渐减小，因此大规模MIMO技术可以通过增加天线数、降低发送功率来提高能量效率。（4）在异构网络中，当宏蜂窝采用传统多天线技术、微蜂窝采用大规模MIMO技术，并且系统采用频段分离的TDD工作方式时，系统不仅可以满足下一代移动通信系统中高速率通信需求，还可以有效避免异构网络中的小区间干扰。
[Abstract]:With the increasing demand of users, high speed, High quality communication system is the research goal of the new generation mobile communication technology. Multi-antenna technology, represented by multiple Input Multiple output (Mimo), is the best way to achieve the above goal. Due to severe inter-cell interference and higher data transmission requirements, the focus of research has turned to large-scale MIMO technology, that is, the use of large-scale antenna arrays (more than ten antennas) at base stations. Compared with traditional MIMO technology, this technology can not only improve the spectrum efficiency of the system, but also improve the communication quality. Moreover, it can effectively reduce the complexity of interference cancellation and the transmission power of the base station. In this paper, the spectrum efficiency, energy efficiency, and system performance of large-scale MIMO technology are studied. Firstly, using the stochastic matrix theory, we study the large scale MIMO technology in a single cell. In a multi-cell downlink system, when the number of antennas tends to infinity, the ultimate performance of the unit precoding and the closed expression of the spectral efficiency of the system are obtained. Secondly, through theoretical derivation and MATLAB simulation, The relationship between two kinds of precoding energy efficiency and antenna number and transmission power is analyzed. Finally, by comparing three different duplex modes, the performance analysis of large-scale MIMO technology applied to heterogeneous networks is presented. The results show that when the transmission power of the base station decreases to 1m of the single antenna base station under the condition that the base station has known complete channel state information (CSI), with the infinite increase of the number of base station antennas, the spectral efficiency of the system tends to be constant. And the limit expression of MRT unit precoding is the same as that of ZF unit precoding. Therefore, the base station can use simple MRT pretreatment to eliminate inter-user, inter-cell interference and fast fading effect. Due to the influence of CSI estimation, the inter-cell interference can not be completely eliminated, but with the decrease of transmission power, the system energy efficiency will be gradually improved with the increase of the number of antennas. However, with the increase of transmission power, the energy efficiency of large-scale MIMO can be improved by increasing the number of antennas and reducing the transmission power. When the microcellular uses large-scale MIMO technology and the system adopts the frequency band separation TDD operation mode, the system can not only meet the high rate communication demand in the next generation mobile communication system, but also can effectively avoid the inter-cell interference in the heterogeneous network.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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