The knowledge of channel covariance matrices is crucial to the design of intelligent reflecting surface (IRS) assisted communication. However, channel covariance matrices may change suddenly in practice. This letter focuses on the detection of the above change in IRS-assisted communication. Specifically, we consider the uplink communication system consisting of a single-antenna user (UE), an IRS, and a multi-antenna base station (BS). We first categorize two types of channel covariance matrix changes based on their impact on system design: Type I change, which denotes the change in the BS receive covariance matrix, and Type II change, which denotes the change in the IRS transmit/receive covariance matrix. Secondly, a powerful method is proposed to detect whether a Type I change occurs, a Type II change occurs, or no change occurs. The effectiveness of our proposed scheme is verified by numerical results.

翻译：信道协方差矩阵的知识对于智能反射面（IRS）辅助通信的设计至关重要。然而在实际应用中，信道协方差矩阵可能发生突变。本文针对IRS辅助通信中上述变化的检测问题展开研究。具体而言，我们考虑由单天线用户（UE）、IRS和多天线基站（BS）组成的上行通信系统。首先根据对系统设计的影响，将信道协方差矩阵变化分为两类：第一类变化表示BS接收协方差矩阵的变化，第二类变化表示IRS发射/接收协方差矩阵的变化。其次，提出一种有效方法用于检测是否发生第一类变化、第二类变化或无变化。数值结果验证了所提方案的有效性。