A New Accurate Volterra-Based Model for Behavioral Modeling and Digital Predistortion of Rf Power Amplifiers

Abstract

A new accurate Volterra-based model is introduced for behavioral modeling and digital predistortion (DPD) of power amplifiers (PAs). This model extends the GMP model with specific cross terms, and these augmented terms significantly increase the model's performance. The proposed model's performance is assessed using a LDMOS Doherty PA driven by two modulated signals (a 4-carrier WCDMA signal and a single carrier 16QAM signal). The experimental results in both behavioral modeling and DPD applications demonstrate that the proposed model outperforms the hybrid memory polynomial-envelope memory polynomial (HME) model and generalized memory polynomial (GMP) model. Compared with the HME model, the proposed model shows an average normalized mean square error (NMSE) improvement of 2.2 dB in the behavioral modeling, average adjacent channel power ratio (ACPR) improvement of 2.8/2.5 dB in the DPD application, and 20% reduction in the number of coefficients. In comparison with the GMP model, the proposed model achieves higher model accuracy and better DPD performance, but reduces approximately 40% of coefficients.

A Modified Generalized Memory Polynomial Model for Rf Power Amplifiers

“…Although the generalized memory polynomial (GMP) [6] model including the cross-band modulation terms is proposed for its high accuracy, a high model complexity is unavoidable when the values of memory depth and nonlinearity order are high. This is because all memory depths have the same nonlinearity order as many predistortion models [7][8][9][10].…”

A Multi-Status Behavioral Model for the Elimination of Electrothermal Memory Effect in DPD System

“…The research on the behavioral model of power amplifiers (PAs) yields many helpful results due to the development of wireless communication technology in the last decade [1][2][3][4][5]. Many new nonlinear memory models, such as general memory polynomial (GMP) [3,4,6], are introduced to describe the output characteristic of power amplifier, and experiment results show that these models exhibit very good performance for the description the characteristic of the wide-band power amplifiers.…”

“…Many new nonlinear memory models, such as general memory polynomial (GMP) [3,4,6], are introduced to describe the output characteristic of power amplifier, and experiment results show that these models exhibit very good performance for the description the characteristic of the wide-band power amplifiers. However, in those works, only the stable characteristic of power amplifiers has been discussed, and the transient characteristic, which is often influenced by a new physical phenomenon called electrothermal memory [7], is ignored in analysis.…”

An Accurate Complexity-Reduced Simplified Volterra Series for Rf Power Amplifiers

“…Volterra series can accurately describe the nonlinearity of PA, but it involves a great number of coefficients [6,7] and is undesirable in practice. Therefore, Volterra-based pruning of the items [8][9][10][11][12][13][14][15][16][17] is essential to practical application. The Memory Polynomial (MP) model [13] contains the diagonal terms of Volterra series.…”

“…The Generalized Memory Polynomial (GMP) [15] combines the MP model with cross items between the signal and lagging and/or leading exponentiated envelope terms. The new simplified Volterra (SV) [16] series combines the GMP model with cross terms between the conjugate signal and lagging and/or leading exponentiated envelope terms. Compared with MP model.…”