Two-Step Simulation Scheme of Power Amplifiers for Digital Predistortion Assessment in 5G Systems

Digital Predistortion (DPD) is a powerful technique for enhancing the linearity of RF Power Amplifiers (PAs) and decreasing distortion effects within communication channels. This paper proposes a new methodology to better predict final Adjacent Channel Leakage Ratio (ACLR) after linearization, giving insight into the PA behavior in DPD. The presented methodology is called Two-Step simulation and employs an adaptive modeling system derived from closed-loop DPD static polynomial systems, enabling PA designers to compare results across various DPD configurations. This approach is faster than a hardware setup and reduces the risk of damaging new PAs due to diverging DPD configurations. The methodology was validated through simulations and measurements of a PA board with a 5G New Radio 100 MHz signal with 8.5 dB Peak-to-A verage Power Ration and centered at 2.6 GHz, which showed an increase in the prediction accuracy of final ACLR, DPD configuration degradation and spectral asymmetries for all tested DPD configurations.