Reducing the computational complexity of the modern wireless communication systems such as massive MIMO configurations is of utmost interest. In this paper, we propose algorithms which can be used to accelerate matrix inversion and reduce the complexity of common spatial multiplexing schemes in massive MIMO systems. Here, we specifically investigate the performance of the proposed methods in systems that utilize STBC (Space-Time Block Code) in the uplink of dynamic massive MIMO systems for different scenarios. A multi-user system in which the base station is equipped with a large number of antennas and each user has two antennas is considered. In addition, users can enter or exit the system dynamically. For a given space-time block coding/decoding scheme, the computational complexity of the receiver will be significantly reduced by employing the proposed methods. The first approach is utilizing Neumann series to approximate the inverse matrix for linear decoders. The second tactic is reducing the computational complexity of the STBC decoders when a user is added to system or removed from it. In the proposed schemes, the matrix inversion for ZF and MMSE decoding is derived from inversing a partitioned matrix and Woodbury matrix identity. Furthermore, the suggested techniques can be utilized when the number of users is fixed but the CSI changes for a particular user. The mathematical equations for both approaches are derived and the complexity of the suggested methods is compared to the direct computation of the inverse matrix. Moreover, the performance of the proposed algorithms is evaluated in terms of the system BER (bit error rate). Evaluations confirm the effectiveness of the proposed approaches.

降低诸如大规模MIMO配置之类的现代无线通信系统的计算复杂度是最重要的。在本文中，我们提出了可用于加速矩阵求逆并降低大规模MIMO系统中常见空间复用方案的复杂度的算法。在这里，我们专门研究了在不同情况下动态大规模MIMO系统的上行链路中利用STBC（空时分组码）的系统中所提出方法的性能。考虑一种多用户系统，其中基站配备有大量天线，每个用户有两个天线。此外，用户可以动态进入或退出系统。对于给定的时空块编码/解码方案，通过采用所提出的方法，接收机的计算复杂度将大大降低。第一种方法是利用Neumann级数来近似线性解码器的逆矩阵。第二种策略是当用户添加到系统中或从系统中删除时，降低STBC解码器的计算复杂性。在提出的方案中，ZF和MMSE解码的矩阵求逆是通过对分区矩阵和伍德伯里矩阵恒等式求逆而得出的。此外，当用户数量固定但CSI对于特定用户改变时，可以利用建议的技术。推导了这两种方法的数学方程，并将所建议方法的复杂性与逆矩阵的直接计算进行了比较。此外，根据系统误码率（BER）评估所提出算法的性能。评估证实了所提出方法的有效性。