Creating an Interference-Free Environment Via Intelligent Reflecting Surface: A Blind Approach Without Knowledge of CSI

We study the problem of interference cancelation with the aid of an intelligent reflecting surface (IRS), where the objective is to determine the reflection coefficients at the IRS such that the interference signals are canceled at the receiver. Specifically, we are interested in a 'blind' scenario where the channel state information (CSI) between the interference sources and the receiver is unknown. To tackle this challenging problem, we propose a sample-efficient blind approach which utilizes a small number of average received signal power measurements to automatically identify a reflection coefficient vector that is orthogonal to the cascaded interference channels and thus nullifies the interference signals at the receiver. Simulation results show that the proposed method can effectively cancel the interference signals and enhance the signal-to-interference-plus-noise ratio (SINR).