论文标题
RIS AID的MIMO通信的关节主动和被动横梁，低分辨率相移
Joint Active and Passive Beamforming for RIS-aided MIMO Communications with Low-Resolution Phase Shifts
论文作者
论文摘要
实际的硬件限制通常会在可重构智能表面（RIS）的元素上施加减少的可用相移数。大多数作品通常会在RIS元素上进行连续的相位，以进行发射和被动的光束形成优化，这可能导致大量性能损失。因此，为了收获RIS辅助的多通多输入多输入（MIMO）通信在现实的相移下的收益，这封信提出了问题提出的问题，以提出问题的提示，以最大程度地提出与传输预编码器和RIS元素相比，可以避免出现明确的离散约束，同时又加入了其效果。为了有效地解决最终的问题，在考虑大型阵列和RIS面板时，得出了一种迭代算法，该算法包括一系列简单的投影。仿真结果表明，所提出的设计可能非常有效，尤其是在低分辨率相移的情况下。
Practical hardware limitations often impose a reduced number of available phase shifts at the elements of a reconfigurable intelligent surface (RIS). Most works often assume continuous phase-shits at the RIS elements for the transmit and passive beamforming optimization, which can lead to substantial performance loss. Therefore, to harvest the gains of RIS-assisted multi-stream multiple-input multiple-output (MIMO) communications under realistic phase shifts, this letter proposes a problem formulation for the maximization of the achievable rate over the transmit precoder and RIS elements, which avoids an explicit discrete constraint while still incorporating its effect. To efficiently tackle the resulting problem when considering large arrays and RIS panels, an iterative algorithm is derived which comprises a sequence of simple projections. Simulation results demonstrate that the proposed design can be very effective, especially with low-resolution phase-shifts.
