Hysteresis nonlinearity modeling and linearization approach for Envelope Tracking Power Amplifiers in wireless systems

Abstract

Novel Dual-Input Single-Output (DISO) behavioral modeling and linearization techniques for Envelope Tracking Power Amplifiers (ET PAs) in wireless application are presented in this paper. The proposed modeling approach applies the Hammerstein structure for the Amplitude-to-Phase (AM/PM) conversion. An extension of the Saleh AM/PM model is also proposed to model the static nonlinearity in the ET PA AM/PM conversion. This paper presents a new linearization technique for ET PAs by inverting the proposed ET PA model and using it as a Digital Predistortion (DPD). The measurement results show that both the proposed model and DPD can clearly outperform both the original Saleh model and the DPD based on the Saleh model inversion. Compared to the state-of-the-art behavioral models for ET PAs, the proposed model and DPD can offer an improved complexity-accuracy trade-off thanks to the lower number of coefficients.