Digital Predistorter Implementation for Wideband Power Amplifiers in New Generation Wireless Systems Based on a Low-Complexity Volterra Series Model

In this article, we provide a novel, expanded, and adapted pruning approach for the Simplified Volterra Series (SVS) model that makes it applicable to a wider range of Power Amplifiers (PAs). The proposed Modified SVS (MSVS) model is then applied in a Digital Predistortion (DPD) architecture to linearize a 25 W Gallium Nitride (GaN) RF PA. A comprehensive and detailed experimental hardware setup is designed for the in-depth testing and validation of the proposed model based DPD architecture, covering PA characterization, model coefficients extraction, and linearization. Our proposed MSVS based DPD significantly reduces the computational cost by at least 60% compared to widely referenced models in the literature while maintaining an optimal balance between accuracy and complexity. Experimental results performed using Long Term Evolution (LTE) signals show a modeling accuracy of −37 dB in terms of Normalized Mean Square Error (NMSE) and a 14 dB reduction in out-of-band distortion in terms of Adjacent Channel Power Ratio (ACPR), compared to the no DPD configuration.