Anchor-Assisted Channel Estimation for Intelligent Reflecting Surface Aided Multiuser Communication

Channel estimation is a practical challenge for intelligent reflecting surface (IRS) aided wireless communication. As the number of IRS elements or IRS-aided users increases, channel training overhead becomes excessively high, which results in long delay and low throughput data transmission. To tackle this challenge, we propose paper new anchor-assisted approach, where two anchor nodes, namely A1 A2, are deployed near facilitating its base station (BS) acquiring cascaded BS-IRS-user channels required Specifically, first scheme, partial state information (CSI) on element-wise gain square common BS-IRS link all obtained at BS via feedback. Then, by leveraging such CSI, efficiently resolved with additional users. While second BS-IRS-A1 A1-IRS-A2 estimated A1. estimate their individual A2-IRS-user simultaneously. Based CSI fed back from A2 users, resolves efficiently. In both schemes, among fixed BS, IRS, anchors large timescale, greatly reduces real-time overhead. Simulation demonstrate that our proposed schemes achieve superior performance as compared to existing under various setups. addition, scheme outperforms one when antennas sufficiently large, vice versa.