Reconfigurable intelligent surface (RIS)-assisted communications appear as a promising candidate for future wireless systems due to its attractive advantages in terms of implementation cost and end-to-end system performance. In this paper, two new multiple-input multiple-output (MIMO) system designs using RISs are presented to enhance the performance and boost the spectral efficiency of state-of-the-art MIMO communication systems. Vertical Bell Labs layered space-time (VBLAST) and Alamouti's schemes have been considered in this study and RIS-based simple transceiver architectures are proposed. For the VBLAST-based new system, an RIS is used to enhance the performance of the nulling and canceling-based sub-optimal detection procedure as well as to noticeably boost the spectral efficiency by conveying extra bits through the adjustment of the phases of the RIS elements. In addition, RIS elements have been utilized in order to redesign Alamouti's scheme with a single radio frequency (RF) signal generator at the transmitter side and to enhance its bit error rate (BER) performance. Monte Carlo simulations are provided to show the effectiveness of our system designs and it has been shown that they outperform the reference schemes in terms of BER performance and spectral efficiency.

中文翻译：

---

可重新配置的智能表面赋能 MIMO 系统

可重构智能表面 (RIS) 辅助通信因其在实施成本和端到端系统性能方面的诱人优势而成为未来无线系统的一个有希望的候选者。在本文中，提出了两种使用 RIS 的新多输入多输出 (MIMO) 系统设计，以增强最先进的 MIMO 通信系统的性能和频谱效率。本研究考虑了垂直贝尔实验室分层时空 (VBLAST) 和 Alamouti 方案，并提出了基于 RIS 的简单收发器架构。对于基于 VBLAST 的新系统，RIS 用于增强基于归零和消除的次优检测程序的性能，并通过调整 RIS 元素的相位来传送额外位，从而显着提高频谱效率。此外，RIS 元件已被用于重新设计 Alamouti 的方案，在发射器侧使用单个射频 (RF) 信号发生器，并提高其误码率 (BER) 性能。提供 Monte Carlo 模拟以显示我们系统设计的有效性，并且已经证明它们在 BER 性能和频谱效率方面优于参考方案。s 方案在发射机侧使用单个射频 (RF) 信号发生器并提高其误码率 (BER) 性能。提供 Monte Carlo 模拟以显示我们系统设计的有效性，并且已经证明它们在 BER 性能和频谱效率方面优于参考方案。s 方案在发射机侧使用单个射频 (RF) 信号发生器并提高其误码率 (BER) 性能。提供 Monte Carlo 模拟以显示我们系统设计的有效性，并且已经证明它们在 BER 性能和频谱效率方面优于参考方案。