This article introduces multiuser multiple-input multiple-output (MU-MIMO) architectures based on non-linear precoding and stream combining techniques using rate-splitting (RS), where the transmitter often has only partial knowledge of the channel state information (CSI). In contrast to existing works, we consider deployments where the receivers may be equipped with multiple antennas. This allows us to employ linear combining techniques based on the Min-Max, the maximum ratio and the minimum mean-square error criteria along with Tomlinson-Harashima precoders (THP) for RS-based MU-MIMO systems to enhance the sum-rate performance. Moreover, we incorporate the Multi-Branch (MB) concept into the RS architecture to further improve the sum-rate performance. Closed-form expressions for the signal-to-interference-plus-noise ratio and the sum-rate at the receiver end are devised through statistical analysis. Simulation results show that the proposed RS-THP schemes achieve better performance than conventional linear and THP precoders.

中文翻译：

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用于 MU-MIMO 系统的带有流组合器的 Tomlinson-Harashima 预编码速率拆分

本文介绍了基于非线性预编码和流合并技术的多用户多输入多输出 (MU-MIMO) 架构，使用速率分割 (RS)，其中发射机通常只了解部分信道状态信息 (CSI) . 与现有工作相比，我们考虑了接收器可能配备多个天线的部署。这允许我们采用基于 Min-Max、最大比率和最小均方误差标准的线性组合技术以及基于 RS 的 MU-MIMO 系统的 Tomlinson-Harashima 预编码器 (THP) 来提高总速率性能. 此外，我们将多分支 (MB) 概念纳入 RS 架构，以进一步提高总速率性能。通过统计分析设计了接收端信干噪比和总和率的闭式表达式。仿真结果表明，所提出的 RS-THP 方案比传统的线性和 THP 预编码器实现了更好的性能。