Error Propagation Reduced Channel Estimation for IRS-aided Multiuser Communications

Intelligent reflecting surface (IRS) has emerged as a promising paradigm to improve the capacity and reliability of a wireless communication system by smartly reconfiguring the wireless propagation environment. To achieve the promising gains of IRS, the acquisition of the channel state information (CSI) is essential, which however is practically difficult since the IRS does not employ any transmit/receive radio frequency (RF) chains in general and it has limited signal processing capability. In this paper, we study the uplink channel estimation problem for an IRS-aided multiuser single-input multi-output (SIMO) system. To alleviate the negative effects caused by error propagation in the existing three-phase channel estimation approach, we propose a novel two-phase channel estimation (2PCE) strategy which can enhance the channel estimation performance with the same amount of channel training overhead as in the existing approach. Simulation results are presented to validate the effectiveness of the 2PCE strategy.