Journal of the Korea Institute of Information and Communication Engineering (한국정보통신학회논문지)

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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Digital Predistortion for Multi-band/Multi-mode Transmission Systems

다중 대역 전송 시스템을 위한 전치왜곡 알고리즘

  • Received : 2011.10.19
  • Accepted : 2011.11.16
  • Published : 2012.01.31
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Abstract

New digital predistortion technique is proposed for power amplifier linearization in multi-band transmission systems. We consider a system where muli-band signals are combined and amplified by a single power amplifier (PA). In this system, the PA output is distorted by the nonlinear cross-products between different band signals as well as their own nonlinear self-products. To compensate these nonlinear effects, we propose a multiple PD structure. Each PD removes the nonlinear cross-products and self-products to mitigate the spectral regrowth for the corresponding band. Since the PD parameters for different bands are linked together, it is difficult to find the PD parameters separately. Thus, we propose an iterative method for finding the PD parameters jointly. For demonstration of the proposed method, multi-band characteristics of PA are extracted from a commercial power amplifier. Computer simulation was executed based on the PA parameters. The simulation results show that the proposed method can effectively linearize the PA and remove spectral regrowth at each signal band.

본 논문에서는 다중 대역 전송 시스템에서 광대역 전력 증폭기의 선형화를 위한 새로운 전치왜곡 기법을 제안한다. 특히, 한 시스템에서 동시에 다중대역/다중모드 신호를 전송함에 있어 다중대역 신호가 하나의 전력 증폭기에 의해 증폭되어 전송되는 시스템을 고려한다. 상호 대역 간 비선형 왜곡을 포함한 비선형 특성을 보상하기 위하여, 본 논문에서는 다중 전치왜곡기 블록을 갖는 새로운 전치왜곡 구조를 제안하며, 다중 전치왜곡기의 계수를 동시에 갱신하는 적응 알고리즘을 제안한다. 제안하는 다중 대역 모델을 검증하기 위하여 상용 증폭기를 사용하여 증폭기 모델을 추출하였으며, 추출된 모델을 기반으로 제안한 알고리즘을 모의실험을 통해 검증하였다. 모의실험 결과는 제안 알고리즘이 효과적으로 다중 전치왜곡기의 계수를 구할 수 있으며, 다중 대역을 효과적으로 선형화 할 수 있음을 보여준다.

Keywords

References

  1. S. C. Cripps, RF power amplifiers for wireless communications, Second edition. Artech House Microwave Library, 2006
  2. B. Razavi, "A 900-MHz/1.8GHz CMOS transmitter for dual-band applications", IEEEJ. Solid-State Cirucits, vol. 34, no. 5, pp. 573-579, May 1999 https://doi.org/10.1109/4.760365
  3. M. Tiebout, "A CMOS fully integrated 1GHz and 2GHz dual band VCO with a voltage controlled inductor," in Proc. IEEE Eropean Solid-State Conf., 2002, pp. 799-802
  4. A katz, R. Gray, and R. Dorval, "Wide/Multiband linearization of TWTAs using predistortion," IEEE Trans. Electron Devices, vol. 56, no. 5, May 2009
  5. H.-J. Choi, H.-Y. Jeong, Y. Kim, J.-S. Lim, C.-D. Kim, and Y.-C. Jeong, "Dual-band predistortion power amplifier for digital cellular and IMT-2000 base-station application," IEEE Asia-Pacific Microwave Conf., 2007.
  6. D. Zhou and V. E. DeBrunner, "Novel Adaptive Nonlinear Predistorters Based on the Direct Learning Algorithm," IEEE Trans. Signal Process., vol. 55, no. 1, pp. 120-133, Jan. 2007. https://doi.org/10.1109/TSP.2006.882058
  7. S. Choi, E.- R.- Jeong, and Y. H. Lee, "Adaptive predistortion with direct learning based on piecewise linear apporximation of amplifier nonlinearity," IEEE J. Select. Topics in Signal Process., vol. 3, no. 3, pp. 397-404, June 2009. https://doi.org/10.1109/JSTSP.2009.2020265
  8. Y. Qian and T. Yao, "Structure for Adaptive Predistortion Suitable for Efficient Adaptive Algorithm Application," Electronics Letters, vol. 38, no. 21, pp. 1282-1283, Oct. 2002.
  9. J. K. Cavers, "Amplifier Linearization Using a Digital Predistorter with Fast Adaptation and Low Memory Requirements," IEEE Trans. Veh. Technol., vol. 39, no. 4, pp. 374-382, Nov. 1990. https://doi.org/10.1109/25.61359
  10. R. Marsalek, P. Jardin, and G. Baudoin, "From Post-distortion to Predistortion for Power Amplifiers Linearization," IEEE Commun. Letters, vol. 7, no. 7, pp. 308-310, July 2003. https://doi.org/10.1109/LCOMM.2003.814714
  11. S. Haykin, Adaptive filter theory, Prentice Hall, 2003