论文标题
与LOS通道的RIS辅助通信的最大似然通道估计
Maximum Likelihood Channel Estimation for RIS-Aided Communications With LOS Channels
论文作者
论文摘要
可重新配置的智能表面（RIS）根据分配给其元素的相移模式来反映传入的信号。最有前途的用例是当用户在RIS的视线（LOS）通道（LOS）通道时，辅助基站与用户之间的通信，但直接通道被阻止。主要的挑战是用有限的资源估算通道，因为非参数估计方法需要与大量RIS元素成比例成正比的试点长度。在本文中，我们开发了一个参数最大似然（ML）通道估计框架，用于将LOS通道估算为RIS。我们证明，所提出的算法只能使用几个飞行员准确地获得通道和首选RIS配置。一个关键的新颖性是，选择了试点传输过程中使用的RIS配置以逐步提高估计准确性。
A reconfigurable intelligent surface (RIS) reflects incoming signals in different ways depending on the phase-shift pattern assigned to its elements. The most promising use case is to aid the communication between a base station and a user when the user has a line-of-sight (LOS) channel to the RIS but the direct channel is blocked. The main challenge is to estimate the channel with limited resources because non-parametric estimation methods require a pilot length proportional to the large number of RIS elements. In this paper, we develop a parametric maximum likelihood (ML) channel estimation framework for estimating the LOS channel to the RIS. We demonstrate that the proposed algorithm can accurately obtain the channel and preferred RIS configuration using only a few pilots. A key novelty is that the RIS configurations used during pilot transmission are selected to progressively improve the estimation accuracy.
