多用户MIMO用户调度方法及性能分析

发布时间：2018-04-30 08:04

本文选题：多用户MIMO + 用户调度　；参考：《电子科技大学》2014年硕士论文

【摘要】：在现代无线移动通信中,多输入多输出(Multiple Input Multiple Output,MIMO)技术通过空间复用可以有效增大系统的频谱利用率和系统容量,因此被广泛使用在3GPP LTE/LTE-Advanced、IEEE WiMAX和WLAN等无线通信标准中。空间复用技术是下行多用户MIMO能够有效提高频谱效率的重要手段,但由于受到移动终端间协作通信实现的限制,使得下行通信中终端联合解码难以实现,为了避免下行终端的联合解码,有研究人员提出发送端的波束成形处理技术。另一方面,基站选择合理的用户组合进行接入通信是有效提高空间复用效率的另一重要环节。而在上行MIMO链路中,由于受到终端尺寸和天线复杂度的制约,难以在终端实现多根天线的配置。虚拟MIMO(Virtual MIMO,V-MIMO)技术的诞生使得这一难题的解决成为了可能。V-MIMO技术是使多个终端可以同时在相同的时频资源上进行数据传输,在基站侧看来,终端侧的多个单天线组成了多天线从而与多天线的基站构成了MIMO结构,由此可以利用空间分集和空间复用技术,提高上行通信的可靠性和总的系统容量。其中,如何选择共信道用户是虚拟MIMO技术的关键,这直接影响了V-MIMO系统的总体性能。这是因为多用户MIMO系统的性能不可避免地受到用户间干扰的限制,选择合适的用户可以减小用户间的干扰从而提高虚拟MIMO系统的频谱效率;反之,用户选择的不合适,系统性能可能还不如未配对的情况。无论下行还是上行MIMO链路,如何选择用户和设计波束成形向量都成为关键的技术环节。波束成形的做法是在传输端用户数据经过传输信道之前乘以预编码向量,或者是在接收端的数据在经过处理之前乘以接收波束成形向量,这样处理使得发送或接收数据的主瓣可以同对应用户信道方向保持一致,同时减少该数据对其他用户的干扰。合理设计波束成形向量可以有效消除或减少用户间的共信道干扰。这些技术要求传输端掌握准确的信道状态信息,但是在实际操作中,信道估计误差是不可避免的,在非完美的信道状态信息下,鲁棒性便成为波束成形和用户调度中的重要课题。本文将从多用户MIMO中的波束成形和用户调度两方面进行研究,主要工作如下:首先总结现有多用户MIMO用户调度和预编码技术的研究现状,分析现有技术特点和适用情况。其次,总结了几种传统的多用户MIMO线性预编码技术和用户调度算法,并对几种传统的用户调度算法进行了仿真对比,分析了各个调度算法的适用场景和性能差异。然后在多用户MIMO下行信道中,由基于SLNR的预编码算法研究分析了两种用户调度和预编码的联合算法,详细描述了其原理和算法流程,并将两种算法和前文提到的算法进行比对,分析总结了所提算法的适用场景。最后在多用户MIMO上行信道中,以已有的基于SINR准则的用户调度算法为参照,提出了一种在全搜索思想下较低复杂度的用户调度算法,详细描述了其算法流程,通过与已有算法的仿真分析说明所提算法在特定场景下的应用优势。
[Abstract]:In modern wireless mobile communications, the Multiple Input Multiple Output (MIMO) technology can effectively increase the spectrum utilization and system capacity of the system by space reuse, so it is widely used in the wireless communication standards such as 3GPP LTE/LTE-Advanced, IEEE WiMAX and WLAN. Space multiplexing technology is the downlink multiuser MIMO energy In order to avoid joint decoding of downlink terminals, researchers put forward beamforming processing techniques at the sending end to avoid the joint decoding of downlink terminals. On the other hand, base stations choose a reasonable user combination. Access communication is another important link to effectively improve the efficiency of space reuse. In the uplink MIMO link, because of the constraints of terminal size and antenna complexity, it is difficult to configure multiple antennas at the terminal. The birth of the virtual MIMO (Virtual MIMO, V-MIMO) technology has made this difficult problem a possible.V-MIMO Technology The multiple terminals can transmit data at the same time frequency resources at the same time. At the base station side, it appears that the multiple antennas at the terminal side constitute a multi antenna and thus constitute the MIMO structure with the base station of the multi antenna. Thus, space diversity and space multiplexing technology can be used to improve the reliability and total system capacity of the uplink communication. How to select the common channel users is the key to the virtual MIMO technology, which directly affects the overall performance of the V-MIMO system. This is because the performance of the multiuser MIMO system is inevitably restricted by the interference between users. The selection of appropriate users can reduce the interference between users and thus improve the spectral efficiency of the virtual MIMO system; on the contrary, the user chooses to choose the system. The system performance may not be as good as unpaired. Whether downlink or uplink MIMO links, how to select users and design beamforming vectors is a key technology. The beamforming method multiplies the precoding vector before the transmission channel is transmitted through the transmission channel, or the data at the receiving end. It is multiplied by receiving beamforming vectors before processing, so that the main lobe of the transmitted or received data can be consistent with the corresponding user channel direction and reduces the interference of the data to other users. A reasonable design of the beamforming vector can effectively eliminate or reduce the common channel interference between users. These techniques require transmission. The channel state information is accurate, but in actual operation, the channel estimation error is inevitable. Under the imperfect channel state information, robustness becomes an important subject in beamforming and user scheduling. This paper will study two aspects of beamforming and user scheduling in multiuser MIMO. The main work is as follows: The current research status of the existing multi-user MIMO user scheduling and precoding technology is summarized, and the existing technology characteristics and application conditions are analyzed. Secondly, several traditional multi-user MIMO Linear Precoding and user scheduling algorithms are summarized, and several traditional user scheduling algorithms are simulated and compared, and the suitability of each scheduling algorithm is analyzed. In the multi-user MIMO downlink channel, two kinds of joint algorithms for user scheduling and precoding are studied and analyzed in the SLNR based precoding algorithm. The principle and algorithm flow are described in detail, and the two algorithms are compared with those mentioned in the previous article. Finally, the application scene of the proposed algorithm is analyzed and summarized. Finally, the application scene of the proposed algorithm is analyzed and summarized. In the multiuser MIMO uplink channel, based on the existing SINR based user scheduling algorithm, a user scheduling algorithm with low complexity under the full search idea is proposed, and its algorithm flow is described in detail. The application advantages of the proposed algorithm in a specific scene are illustrated by the simulation analysis of the existing algorithms.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

【共引文献】