LAUSR

Channel state information (CSI) acquisition is a crucial but challenging task in reconfigurable intelligent surface (RIS)-aided wireless systems due to the passive property of RIS. In this letter, we investigate a novel anchor-assisted channel estimation strategy for RIS-aided multiuser communication systems. Specifically, for the estimate of each cascade reflecting link, we decompose it into three components: The common channel from an anchor to the RIS, the amplitude ratios of the corresponding RIS-BS channel, and user-RIS channel related to the common channel. Two amplitude ratios are estimated firstly and then the common channel can be resolved with significantly reduced training signals by leveraging the known amplitude ratios. Simulation results show the superiority of our proposed anchor-assisted channel estimation method as compared to the benchmarks.