To reduce the computational complexity and channel estimation overhead for multi-intelligent reflecting surface (IRS)-assisted millimeter wave (mmWave) multiple-input multiple-output (MIMO) communication, we consider a joint design of the hybrid precoders at the base station and the passive precoders at the IRSs to maximize the ergodic spectral efficiency by exploiting the twin-timescale channel state information (CSI). Specifically, the digital precoder is designed according to the instantaneous CSI of a reduced-dimensional assist channel matrix, while the IRS passive reflection coefficient matrices and the analog precoder are optimized using the statistical CSI of all links. However, such a design problem is challenging to solve due to the non-convexity and the twin timescale. This work proposes efficient algorithms to jointly design the precoders, where the update of the IRS reflection coefficient matrices is independent of the hybrid precoders and the design of the analog precoder is independent of the digital precoder. Simulation results demonstrate the effectiveness of the proposed algorithms and provide the application scenes of the fully-connected and subarray-connected architectures. The results also show that the ergodic spectral efficiency for the fully-connected architecture using the twin-timescale CSI can approach that using the existing CSI schemes with less channel estimation overhead and computational complexity.

中文翻译：

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使用双时间尺度信道状态信息的多 IRS 辅助毫米波 MIMO 通信

为了降低多智能反射面 (IRS) 辅助毫米波 (mmWave) 多输入多输出 (MIMO) 通信的计算复杂度和信道估计开销，我们考虑在基站联合设计混合预编码器和IRS 的被动预编码器通过利用双时间尺度信道状态信息 (CSI) 来最大化遍历频谱效率。具体而言，数字预编码器是根据降维辅助信道矩阵的瞬时CSI设计的，而IRS无源反射系数矩阵和模拟预编码器则使用所有链路的统计CSI进行优化。然而，由于非凸性和双时间尺度，这样的设计问题难以解决。这项工作提出了有效的算法来联合设计预编码器，其中 IRS 反射系数矩阵的更新独立于混合预编码器，模拟预编码器的设计独立于数字预编码器。仿真结果证明了所提算法的有效性，并提供了全连接和子阵列连接架构的应用场景。结果还表明，使用双时间尺度 CSI 的全连接架构的遍历频谱效率可以接近使用现有 CSI 方案的信道估计开销和计算复杂度。仿真结果证明了所提算法的有效性，并提供了全连接和子阵列连接架构的应用场景。结果还表明，使用双时间尺度 CSI 的全连接架构的遍历频谱效率可以接近使用现有 CSI 方案的信道估计开销和计算复杂度。仿真结果证明了所提算法的有效性，并提供了全连接和子阵列连接架构的应用场景。结果还表明，使用双时间尺度 CSI 的全连接架构的遍历频谱效率可以接近使用现有 CSI 方案的信道估计开销和计算复杂度。