Modified Magnitude-Selective Affine Function-Based Digital Predistorter for Power Amplifiers

Abstract

A modified magnitude-selective affine function-based (M-MSA) model is proposed for radio frequency power amplifier in this paper. Using linear term and second-order terms, the model replaces the first-order term and the second-order term with phase in the I-MSA model, eliminating the coordinate rotation digital computer (CORDIC) algorithm and decreasing the number of coefficients by (M+1)K. Complexity of the proposed model is lower than the I-MSA model, and the model coefficients are extracted by the least-square method A 4-carrier long-term evolution (LTE) signal of 20MHz bandwidth is used as the excitation in the experiment. The experimental results show that the M-MSA model have nearly the same adjacent channel power ratio (ACPR) and normalized mean square error (NMSE) as the I-MSA model, and the M-MSA model has lower hardware complexity and higher operating efficiency.