The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
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Linearity Enhancement of RF Power Amplifier Using Digital Pre-Distortion Based on Affine Projection Algorithm

Affine Projection 알고리즘에 기초하여 구현한 디지털 전치왜곡을 이용한 RF 전력증폭기의 선형성 향상

  • 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)
  • 성연중 (한국항공대학교 항공전자 및 정보통신공학부) ;
  • 조춘식 (한국항공대학교 항공전자 및 정보통신공학부) ;
  • 이재욱 (한국항공대학교 항공전자 및 정보통신공학부)
  • Received : 2011.12.30
  • Accepted : 2012.03.23
  • Published : 2012.04.30
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Abstract

In this paper, we design a digitally pre-distorted RF power amplifier operating in 900 MHz band. The linearity of RF power amplifier is improved by employing the digital pre-distortion(DPD) based on affine projection(AP) algorithm, where the look-up table(LUT) method is used with non-linear indexing. The proposed DPD with AP algorithm is compared with that with normalized least mean square(NLMS) algorithm, applied to the RF power amplifier. A commercial power amplifier module is used for verification of the proposed algorithm which shows improvement of adjacent channel leakage ratio(ACLR) by about 21 dB.

본 논문에서는 900 MHz 대역에서 동작하는 RF 전력증폭기의 선형성 향상을 위한 디지털 전치 왜곡을 구현하였다. Affine Projection(AP) 알고리즘에 기초한 디지털 전치 왜곡을 통하여 RF 전력증폭기의 선형성이 향상되는 것을 입증하였으며, 디지털 전치 왜곡은 Look-up Table(LUT) 방식으로 구현하였다. AP 알고리즘에 기초한 DPD 시스템과 Normalized Least Mean Square(NLMS) 알고리즘에 기초한 DPD 시스템의 성능을 비교하여 AP 알고리즘을 사용한 DPD 시스템의 성능 향상을 검증하였다. 실제 측정을 위하여 상용 증폭기를 사용하였으며, 제안한 방법을 사용하여 인접 채널 누설비(ACLR)를 약 21 dB까지 개선시킬 수 있었다.

Keywords

References

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