Downlink beam forming method of IRS-assisted cloud access network of non-ideal CSI

The invention discloses a non-ideal CSI (Channel State Information) IRS (Inter-Reference Signal) assisted cloud access network downlink beam forming method, which is characterized in that a multi-antenna BBU (Base Band Unit) pool communicates with a plurality of single-antenna users through a multi-antenna RRH (Remote Radio Head), processes baseband signals through point-to-point compression or multivariate compression, and sends quantized bits to the RRH through a forward link; a plurality of smart reflectors (IRSs) are deployed near the RRH to assist wireless forward links and access links at different time slots. In order to improve the system sum rate, joint optimization is carried out on the transmitting beam forming matrix of the BBU pool and the RRH, the phase shift matrix of the reflecting surface and the forward transmission quantization noise covariance matrix, and the downlink transmission rate of the cloud access network communication system can be effectively improved when channel state informati