论文标题
地下辅助抗块MMWave通信系统的稀疏阵列
Sparse Array of Sub-surface Aided Anti-blockage mmWave Communication Systems
论文作者
论文摘要
最近，可重新配置的智能表面（RISS）引起了密集的关注，以增强毫米波（MMWave）通信系统的覆盖范围。但是，现有作品主要将RIS视为整个统一平面，当RIS极大时，可能会安装在建筑物的立面上。为了解决这个问题，在本文中，我们提出了RIS的一个稀疏的子表面（SAOS）体系结构，其中包含几个矩形形状的子表面，称为RIS瓷砖，可以稀疏地部署。得出了SAOS辅助系统的近期光谱效率，并评估了SAOS设计的性能影响。基于近似值的光谱效率，我们为每个RIS瓷砖获得了最佳反射系数设计。分析结果表明，接收到的信噪比可以分别在强和弱的LOS场景下分别与RIS元素的数量进行四次和线性增长。此外，我们考虑了SAOS的MMWave系统中的可见区域（VR）现象，发现RIS瓷砖之间的最佳距离应该产生总的SAOS VR，几乎覆盖了整个盲目覆盖面积。数值结果验证了近似值光谱效率的紧密度，并证明了系统性能出色。
Recently, reconfigurable intelligent surfaces (RISs) have drawn intensive attention to enhance the coverage of millimeter wave (mmWave) communication systems. However, existing works mainly consider the RIS as a whole uniform plane, which may be unrealistic to be installed on the facade of buildings when the RIS is extreme large. To address this problem, in this paper, we propose a sparse array of sub-surface (SAoS) architecture for RIS, which contains several rectangle shaped sub-surfaces termed as RIS tiles that can be sparsely deployed. An approximated ergodic spectral efficiency of the SAoS aided system is derived and the performance impact of the SAoS design is evaluated. Based on the approximated ergodic spectral efficiency, we obtain an optimal reflection coefficient design for each RIS tile. Analytical results show that the received signal-to-noise ratios can grow quadratically and linearly to the number of RIS elements under strong and weak LoS scenarios, respectively. Furthermore, we consider the visible region (VR) phenomenon in the SAoS aided mmWave system and find that the optimal distance between RIS tiles is supposed to yield a total SAoS VR nearly covering the whole blind coverage area. The numerical results verify the tightness of the approximated ergodic spectral efficiency and demonstrate the great system performance.
