A beamforming and combining method for a multi-user large multiple-input multiple-output (MIMO) system is proposed, in this study. A transmitter is equipped with a very large number of antennas to serve many users. At the transmitter, a group of antennas is allocated to each user. For a particular group of antennas, a specific beamforming vector is employed at the transmitter for transmission of a signal of a specific user. At the user end, a distinct combining vector is utilised for detecting the transmitted signal. In the proposed scheme, first, the interference due to unwanted signals of undesired users is nullified by using the concept of null space. Then the method of maximum ratio transmission is used to calculate the beamforming vector. The calculation of combining vector depends upon the maximum eigenvalue criterion. The analytical performance of the proposed method is discussed in terms of symbol error rate (SER). An expression of SER is derived by using the moment generating function approach. It is shown by simulations and analysis that the proposed scheme performs better if more antennas are equipped either at the transmitter or users.

中文翻译：

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多用户大型MIMO通信系统的波束成形和合并

提出了一种多用户大型多输入多输出（MIMO）系统的波束形成和合并方法。发射机配备了大量天线，可以为许多用户服务。在发射机处，一组天线分配给每个用户。对于特定的一组天线，在发射机处采用特定的波束成形矢量来传输特定用户的信号。在用户端，不同的组合矢量被用于检测发射的信号。在提出的方案中，首先，通过使用以下概念来消除由于不希望的用户的不想要的信号引起的干扰：空值空间。然后使用最大比率传输的方法来计算波束形成矢量。组合矢量的计算取决于最大特征值准则。根据符号错误率（SER）讨论了该方法的分析性能。SER的表达式是通过使用矩生成函数方法得出的。通过仿真和分析表明，如果在发射机或用户处安装更多天线，则所提出的方案会更好地执行。