Summary
A new design of power amplifier’s (PA) digital pre-distortion (DPD) model with recursive system identification algorithm based on H-infinite robust control is proposed in this study to improve the accuracy of the model without increasing the computational cost too much. With the development of hardware technology, the linearization of power amplifiers with large bandwidth and high adjacent leakage makes the traditional models need to be implemented by high order nonlinear operation, which results in a decrease in the accuracy of the model and an increase in the calculation cost of the model. Based on the framework of generalized memory polynomial model, this study uses the lower-order nonlinear piecewise function with cross-memory combination term to replace the higher-order nonlinear and implements the design of a new basis function model. In the identification of basis function model, this study designs an identification algorithm based on H-infinite robust control, which deals with the identification of PA system and limits the error to a certain disturbance range. To reduce the computational cost, a low order controller design is solved by linear matrix inequality, and the resulting increase in the disturbance range will be eliminated by the extended Kalman filter to improve the accuracy. In this study, the predistortion simulation results based on the input and output data of PA with large bandwidth and high adjacent leakage are presented to demonstrate the superiority of the model and algorithm in dealing with similar nonlinear system identification problems.
