Decorrelation-Based Concurrent Digital Predistortion With a Single Feedback Path

• Published in: IEEE transactions on microwave theory and techniques Vol. 66; no. 1; pp. 280 - 293
• Main Authors: Abdelaziz, Mahmoud, Anttila, Lauri, Kiayani, Adnan, Valkama, Mikko
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 3GPP LTE-Advanced; Adaptive filters; Baseband; Broadband; carrier aggregation (CA); Complexity; concurrent linearization; Decorrelation; digital predistortion (DPD); dual band power amplifiers (PAs); Feedback; frequency division duplexing (FDD); Learning; Mobile communication systems; Nonlinear distortion; Predistortion; Radio frequency; Receivers; spectrally agile radio; State of the art; Transmitters; Wireless communications
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2017.2706688

In this paper, a novel decorrelation-based concurrent digital predistortion (DPD) solution is proposed for dual-band transmitters (TXs) employing a single wideband power amplifier (PA), and utilizing only a single feedback receiver path. The proposed decorrelation-based parameter learning solution is both flexible and simple, and operates in a closed-loop manner, opposed to the widely applied indirect learning architecture. The proposed decorrelation-based learning and DPD processing can also be effectively applied to more ordinary single carrier/band transmissions, as well as generalized to more than two transmit bands. Through a comprehensive analysis covering both the DPD parameter learning and the main path processing, it is shown that the complexity of the proposed concurrent DPD is substantially lower compared with the other state-of-the-art concurrent DPD methods. Extensive set of simulation and RF measurement results are also presented, using base-station PAs as well as a commercial LTE-Advanced mobile PA, to evaluate and validate the effectiveness of the proposed DPD solution in various real world scenarios, incorporating both single-band and dual-band TX cases. The simulation and RF measurement results demonstrate excellent linearization performance of the proposed concurrent DPD, even outperforming current state-of-the-art methods, despite the significantly lower complexity.