Channel Estimation With Reconfigurable Intelligent Surfaces--A General Framework
Channel Estimation With Reconfigurable Intelligent Surfaces--A General Framework
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DOI：
10.1109/jproc.2022.3170358
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发表时间：
2022-05-09
影响因子：
20.6
通讯作者：
Li, Ming
中科院分区：
文献类型：
--
作者：
Swindlehurst, A. Lee;Zhou, Gui;Li, Ming
在无线通信系统中，从可重构智能表面（RIS）中最佳地提取可用的优点需要估计去往和来自RIS的信道。当RIS由没有任何感测或数据处理能力的无源元件组成时，确定这些信道的过程是复杂的，并且因此，信道必须由非共址设备（通常是控制基站（BS））间接估计。在这篇文章中，我们从一个基本的角度来研究基于无源RIS系统的信道估计。我们研究了各种可能的信道模型和模型的可识别性，作为训练期间RIS的可用导频数据和行为的函数。特别是，我们将考虑的情况下，有和没有视线传播，单天线和多天线配置的用户和BS，相关和稀疏的信道模型，单载波和宽带正交频分复用（OFDM）的情况下，用户和BS之间的直接链接的可用性，利用先验信息，以及一些其他特殊情况。我们进一步进行模拟的代表性算法和比较其性能的各种信道模型，使用相关的克拉美-拉奥界限。
Optimally extracting the advantages available from reconfigurable intelligent surfaces (RISs) in wireless communications systems requires estimation of the channels to and from the RIS. The process of determining these channels is complicated when the RIS is composed of passive elements without any sensing or data processing capabilities, and thus, the channels must be estimated indirectly by a noncolocated device, typically a controlling base station (BS). In this article, we examine channel estimation for passive RIS-based systems from a fundamental viewpoint. We study various possible channel models and the identifiability of the models as a function of the available pilot data and behavior of the RIS during training. In particular, we will consider situations with and without line-of-sight propagation, single-antenna and multi-antenna configurations for the users and BS, correlated and sparse channel models, single-carrier and wideband orthogonal frequency-division multiplexing (OFDM) scenarios, availability of direct links between the users and BS, exploitation of prior information, as well as a number of other special cases. We further conduct simulations of representative algorithms and comparisons of their performance for various channel models using the relevant Cramer-Rao bounds.