An Average Power Tracking Method for Wideband Highly Nonlinear Power Amplifiers

An accurate average power tracking method is presented to track and compensate the fluctuation of power amplifier (PA) output during updates of digital predistorter. Firstly, joint distortion probability distribution (JDPD) of the predistorter input signal and PA compression state is presented to extract the average power gain fluctuation related to the nonlinearity of the PA. The accurate PA compression state is extracted by linear-zone-reposition technique. Then, the average power gain fluctuation related to PA memory is obtained assisted by the predistortion model. The PA output power fluctuation is well controlled through the proposed method. Results from experiments show that the performance of DPD improves at least 3 dB for long time experiments when the proposed method is used for wideband highly nonlinear PA.