Intelligent Reflecting Surface Configuration With Historical Channel Observations

In this letter, we consider the intelligent-reflecting-surface (IRS)-assisted single-user multiple-input single-output downlink communication system, in which multiple IRSs are deployed to improve the propagation condition. Our objective is to configure the phase shift matrices of all the IRSs by exploiting the statistical channel state information (CSI). In particular, two effective algorithms are proposed, which learns the statistical CSI from the historical channel observations. Numerical results show that significant performance gain is achieved especially when the channel randomness is low.