The Journal of the Institute of Internet, Broadcasting and Communication (한국인터넷방송통신학회논문지)

The Institute of Internet, Broadcasting and Communication (한국인터넷방송통신학회)
권호 표지
DOI QR코드

DOI QR Code

A Robustness Performance Improvement of QE-MMA Adaptive Equalization Algorithm based on Dithering

Dithering을 이용한 QE-MMA 적응 등화 알고리즘의 Robustness 성능 개선

  • Lim, Seung-Gag (Dept. of Information and Communication, Kongju National University)
  • 임승각 (공주대학교 정보통신공학부 정보통신공학 전공)
  • Received : 2017.02.20
  • Accepted : 2017.06.09
  • Published : 2017.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

This paper relates with the robustness performance improvement of QE-MMA (Quantized Error-MMA) adaptive equalization algorithm based on the dithering in order to reduce the intersymbol interference by nonlinear distortion occurs at channel. The QE-MMA was appeared for the easiness of H/W implementation in place of multiplication to shifting in the tap coefficient updates applying the power-of-two operation to the magnitude of error signal in currently SE-MMA, it's performance were degraded by this. For improving it's performance, the proposed DQE-MMA adds the dither signal which has constant statistical characteristics in the prestage of power-of-two operation. It was confirmed by simulation that the DQE-MMA gives better robustness performance than current QE-MMA in the same channel and signal to noise ratio.

본 논문은 채널에서 발생되는 비선형 찌그러짐에 의한 부호간 간섭을 줄이기 위하여 dithering에 의한 QE-MMA 적응 등화 알고리즘의 robustness 성능 개선에 관한 것이다. QE-MMA는 기존 SE-MMA에서 오차 신호의 크기를 power-of-two 연산을 적용하여 탭 계수 갱신시 필요한 승산을 천이로 대체하여 H/W 응용을 용이하도록 등장하였으나, 이로 인한 적응 등화 성능이 열화된다. 이를 개선하기 위하여 제안 방식인 DQE-MMA (Dithere Quantized Error-MMA)에서는 power-of-two 연산의 전 단계에서 일정한 통계 특성을 갖는 dither 신호를 부가한다. 동일한 채널과 신호대 잡음비에서 제안 방식인 DQE-MMA가 기존 QE-MMA보다 개선된 robustness 성능을 얻을 수 있음을 시뮬레이션으로 확인하였다.

Keywords

References

  1. J. Yang, J. J. Weren, G. A. Dumont, "The Multimodulus Blind Equalization Algorithm", 13th Int. Conf. D.S.P. Processing, pp. 127-130, 1997. DOI: https://doi.org/10.1109/TCOMM.205.855017
  2. R.M.Gray, T.G.Stockham, "Dithered Quantizers", IEEE Trans. on Information Theory, Vol.39, No.3, pp. 805-812, May 1993. DOI: https://doi.org/10.1109/ISIT.1991.695075
  3. Eweda E., "Convergence Analysis and Design of an Adaptive Filter with Finite-Bit Power-of-Two Quantized Error", IEEE Trans. on Circuit and Systems", Vol.39, No.2, pp. 113-115, Feb. 1992. DOI: https://doi.org/10.1109/82.205815
  4. K. Banovic, R. Lee, E.A.Raheem, M.A.S.Khalid, "Computationally-Efficient Method for Blind Adaptive Equalization", 48th Middlewest Symp. on Circuits and Systems, Vol.1. pp. 341-344, 2005. DOI: https://doi.org/10.1109/MWSCAS.2005.154108
  5. D.Brown, P.Schniter, J.C.R.Johnson, "Computationally Efficient Blind Equalization", Proc. Allerton Conf. on Communications, Control and Computing, Monticello, IL, pp. 54-63, Oct. 1997.
  6. P.Schniter, C.R.Johnson, "Dithered Signed-Error CMA : Robust, Computationally Efficient Blind Adaptive Equalization" IEEE Trans. on Signal Processing, Vol.47, No.6, pp. 1592-1603, June 1999. DOI: https://doi.org/10.1109/78.765129
  7. S. G. Lim, "Performance Improvement of MMA Adaptive Equalization Algorithm by using the Constellation Reduction in QAM Signal", Jour. on I.I.B.C., Vol.14, No.5, pp.103-109, Sep. 2014.
  8. S. G. Lim, "The Performance Comparison of CR-CMA and CM-CMA Adaptive Equalization in 16-QAM Signal", Jour. on I.W.I.T., Vol. 11, No. 3, pp.115-120, June 2011.