论文标题
RIS AID的MMWave Communications的基于3D定位的渠道估计方法
A 3D Positioning-based Channel Estimation Method for RIS-aided mmWave Communications
论文作者
论文摘要
毫米波（MMWave）通信的基本挑战是阻止对象的敏感性。缓解此问题的一种方法是使用可重构智能表面（RIS）。然而，由于RIS上的被动反映元素大量，渠道估计是一项艰巨的任务。在本文中，我们基于本地化方法解决了RIS AID的MMWave通信系统的渠道估计。拟议的想法包括利用MMWave频道的稀疏性和RIS的拓扑结构。特别是，我们首先提出反射单元集（RU）的概念，以提高RIS的灵活性。然后，我们提出了一种基于RUS的新型共面最大似然（CML）3D定位方法，并为定位方法得出CRAMER-RAO下限（CRLB）。此外，我们开发了一种具有低计算复杂性的基于有效定位的通道估计方案。与最先进的方法相比，我们提出的方法需要较少的频道获取时间频率资源，因为复杂性与RIS的总大小无关，但取决于RUSS的大小，这只是RIS的一小部分。模拟中证实了巨大的性能增长，这证明了该方法的有效性。
A fundamental challenge in millimeter-wave (mmWave) communication is the susceptibility to blocking objects. One way to alleviate this problem is the use of reconfigurable intelligent surfaces (RIS). Nevertheless, due to the large number of passive reflecting elements on RIS, channel estimation turns out to be a challenging task. In this paper, we address the channel estimation for RIS-aided mmWave communication systems based on a localization method. The proposed idea consists of exploiting the sparsity of the mmWave channel and the topology of the RIS. In particular, we first propose the concept of reflecting unit set (RUS) to improve the flexibility of RIS. We then propose a novel coplanar maximum likelihood-based (CML) 3D positioning method based on the RUS, and derive the Cramer-Rao lower bound (CRLB) for the positioning method. Furthermore, we develop an efficient positioning-based channel estimation scheme with low computational complexity. Compared to state-of-the-art methods, our proposed method requires less time-frequency resources in channel acquisition as the complexity is independent to the total size of the RIS but depends on the size of the RUSs, which is only a small portion of the RIS. Large performance gains are confirmed in simulations, which proves the effectiveness of the proposed method.
