A simple wideband digital predistortion system based on improved Powell algorithm

摘要

In order to solve the analog-to-digital converter (ADC) sampling rate in the traditional digital predistortion (DPD) system must be several times the bandwidth of the original signal to cover the out-of-band intermodulation components caused by nonlinear radio frequency power amplifiers (PA), low-cost ADC cannot meet today's demand problems. This paper proposes a robust iterative DPD coefficient extraction algorithm based on Powell algorithm and random demodulation. This method applies an improved Powell algorithm to a DPD parameter extraction system. The simulation studies the linearization performance of the system. The simulation show that when the system feedback bandwidth is equal to the original signal bandwidth, satisfactory linearization performance can be obtained. In addition, different from LM algorithm, Powell algorithm does not require partial derivatives of the estimated parameters, the system is simplified.