Browse > Article
http://dx.doi.org/10.5515/KJKIEES.2011.22.4.7430

Linearity Enhancement of RF Power Amplifier Using Digital Predistortion with Tanh as a Nonlinear Indexing Function  

Seong, Yeon-Jung (School of Electronics, Telecommunication and Computer Engineering, Korea Aerospace University)
Cho, Choon-Sik (School of Electronics, Telecommunication and Computer Engineering, Korea Aerospace University)
Lee, Jae-Wook (School of Electronics, Telecommunication and Computer Engineering, Korea Aerospace University)
Publication Information
The Journal of Korean Institute of Electromagnetic Engineering and Science / v.22, no.4, 2011 , pp. 430-439 More about this Journal
Abstract
In this paper, we design a digital predistortion(DPD) for linearity enhancement of RF power amplifier operating in 900 MHz band. We verify improvement of linearity by comparing the proposed DPD using tanh as a nonlinear indexing function and the DPD using linear indexing function based on signal amplitude. The digital predistortion is realized by look-up table(LUT) method, and the Saleh model is employed for power amplifier modeling, then a commercial power amplifier module is used for measurement. The LUT has 256 tables, and the NLMS(Normalized Least Mean Square) algorithm was utilized for an adaptive algorithm for estimation. As a result, we improve the ACLR(Adjacent Channel Leakage Ratio) by around 15 dB.
Keywords
Digital Predistortion; Power Amplifier; Indexing Function; Look-Up Table; tanh;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Y. Y. Woo, J. Kim, J. Yi, S. Hong, I. Kim, J. Moon, and B. Kim, "Adaptive digital feedback predistortion technique for linearizing power amplifiers", IEEE Trans. Microwave Theory and Tech., vol. 55, no. 5, pp. 932-940, May 2007.   DOI
2 B. Shi, et al., "Effects of look-up table size on adaptive predistortion linearizer systems with error cources", 33rd European Microwave Conference, vol. 3, pp. 1231-1234, Oct. 2003.
3 J. K. Cavers, "Optimum indexing in predistorting amplifier linearizers", IEEE Vehicular Technology Conference, vol. 2, pp. 676-680, May 1997.
4 J. K. Cavers, "Optimum table spacing in predistorting amplifier linearizers", IEEE Trans. Vehicular Tech., vol. 48, no. 5, pp. 1699-1705, Sep. 1999.   DOI
5 Simon Haykin, Adaptive Filter Theory, Fourth Edition, Prentice Hall, pp. 320-343, 2004.
6 K. J. Muhonen, M. Kavehrad, and R. Krishnamoorthy, "Look-up table techniques for adaptive digital predistortion: A development and comparison", IEEE Trans. Veh. Technol., vol. 49, no. 5, pp. 1995-2002, Sep. 2000.   DOI
7 F. Zavosh, M. Thomas, C, Thron, T, Hall, D. Anderson, D. Ngo, and D. Runton, "Digital predistortion techniques for RF power amplifiers with CDMA applications", Microw. J., Oct. 1999.
8 Tak Su Moon, Choon Sik Cho, Jae W. Lee, and Young Ho Jung, "Adaptive digital predistortion for the power amplifiers based on look-up table with tanh as a nonlinear indexing function", Asia-Pacific Microwave Conference, Dec. 2008.