Publication Journal: IEEE Transactions on Microwave Theory and Techniques

Title: Digital Predistortion for Concurrent Dual-Band Transmitters Using 2D Modified Memory Polynomials

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: Accepted in 2012, to be published in 2013

Abstract:  Cross-band modulation effects in the concurrent dual-band transmitters are quite noticeable for the linearization. This paper proposes a novel two-dimensional modified memory polynomial (2D-MMP) technique to compensate for nonlinear distortion in the concurrent dual-band transmitters. By taking into account the cross-band modulation effects, the 2D-MMP model is developed by properly modifying the envelope terms of the conventional memory polynomial (MP) model. This makes the model complexity of the 2D-MMP model significantly reduced compared to the prior 2D-DPD model in previous work. However, the linearization ability of the 2D-MMP model is still retained. Simulations prove that the 2D-MMP model is quite robust to different PA models. Experimental measurements were carried out for a dual-band class-AB PA exhibiting mild nonlinearity and a highly nonlinear dual-band Doherty PA. The results show that the 2D-MMP model can achieve nearly the same linearization accuracy compared to the 2D-DPD model, with much less coefficients. Less than –52 dBc adjacent channel power ratios (ACPRs) for the dual-band class-AB PA and –50 dBc ACPRs for the dual-band Doherty PA in the dual bands were achieved.

Email: liuyj04@163.com