Publication Journal: IEEE Transactions on Microwave Theory and Techniques

Title: Modified Least Squares Extraction for Volterra Series Digital Predistorter in The Presence of Feedback Measurement Errors

Authors: You-Jiang Liu, Wenhua Chen, Senior Member, IEEE, Jie Zhou, Bang-Hua Zhou, and Fadhel M. Ghannouchi, Fellow, IEEE

Author Affiliations:  1. Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China;    2.Department of Engineering Physics, Tsinghua University, Beijing 100084, China; 3.Department of Electronic Engineering, Tsinghua University, Beijing 100084, China;    4. Intelligent RF Radio Laboratory (iRadio Lab), Department of Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada T2N 1N4.

Status: Published in Vol. 60, Issue 11, 2012

Abstract:  Measurement errors (in-phase/quadrature imbalance, dc offset, and nonlinearity) in the feedback path can adversely affect the linearization performance of digital predistorter (DPD) for RF power amplifiers (PAs). In this paper, a generalized analysis for the Volterra-series DPD system is presented in the presence of feedback measurement errors. It shows that the DPD coefficients are biased due to these errors. A modified least squares (MLS) method is then proposed for DPD coefficients extraction, which can eliminate the detrimental effect of feedback measurement errors without using a post-compensator. The proposed MLS method has the advantage of being free of behavioral modeling for the feedback path or the post-compensator. However, it can still achieve comparable performance as the state-of-the-art. The performance of the MLS method is validated with both simulations and experiments. The measurement results show that, when a nonideal feedback path is employed to capture the PA output, the proposed MLS method can still ensure a high linearization performance of the DPD, and the results are nearly the same as that when an ideal feedback path is used.

Email: liuyj04@163.com

URL: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6297494&contentType=Early+Access+Articles&refinements%3D4291944245%26queryText%3Dpredistorter