Intelligent reflecting surface two-stage channel estimation method based on millimeter wave combined structure

The invention discloses an intelligent reflecting surface two-stage channel estimation method based on a millimeter wave combined structure, and the method comprises the steps: constructing an uplink millimeter wave MIMO system assisted by an intelligent reflecting surface, and collecting received signals at different moments; deriving a beam space model with angle expansion of a millimeter wave channel, and proving that the beam space model is combined with a sparse and low-rank structure; reconstructing a time domain receiving signal model into a low-rank matrix sampling form, proposing an improved rank operator, and finishing denoising processing of a receiving signal by using a low-rank matrix approximation algorithm; defining a cascade channel virtual beam space matrix, introducing a vec operator and a Kronecker product, and converting a channel model into a sparse signal recovery problem; and the final estimation of the direct channel and the cascade channel is completed by combining the recovered virtu