Iterative nonlinear precoding and feedback for multi-user multiple-input multiple-output (MU-MIMO) with channel state information (CSI) impairments

A method for implementing iterative nonlinear precoding (NLP) and feedback in a Multi-User Multiple-Input Multiple-Output (MU-MIMO) system, the method comprising:

• estimating an effective precoded channel;
• quantizing the effective precoded channel;
• suppressing quantization errors associated with the quantized effective precoded channel to obtain quantized estimates for the effective precoded channel by scaling up elements at a right interference part or triangular of an effective precoded channel matrix associated with the effected precoded channel to a power level of elements or at a left interference part or triangular of the effective precoded channel matrix before quantization using at least one of the following:
• a scalar, booster, or a fixed value or number and scaling back the power level of the elements at the right interference part of the effective precoded channel matrix after quantization;
• and
• feeding back at least one of the following:
• the quantized estimates of the effective precoded channel;
• the quantization errors;
• a square amplitude of the quantization errors;
• and a Channel Quality Indicator (CQI) generated based on the quantization error to implement an NLP scheme in the MU-MIMO system to improve spectrum usage efficiencies.