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The Performance Comparison of MMA and S-MMA Adaptive Equalization Algorithm for QAM Signal

QAM 신호에대한 MMA와 S-MMA 적응 등화 알고리즘의 성능 비교

  • Kang, Dae-Soo (Dept. of Information and Communication, Kongju National University) ;
  • Lim, Seung-Gag (Dept. of Information and Communication, Kongju National University)
  • 강대수 (공주대학교 정보통신공학부) ;
  • 임승각 (공주대학교 정보통신공학부)
  • Received : 2013.01.02
  • Accepted : 2013.02.08
  • Published : 2013.02.28

Abstract

This paper deals with the performance comparison of blind adaptive equalization algorithm, the MMA and S-MMA, that is used for compensation of the amplitude and phase distortion simultaneously which occurs in the time dispersive channel. The present CMA algorithm is possible to compensates the amplitude only, but not in phase, so it needs to the another additional circuit for compensating the phase. In order to overcoming the abovemensioned shorthand, the improved cost function is applied to the MMA algorithm. In MMA algorithm, the error is consists of the dispersion constant only, but in S-MMA, the error is consists of the dispersion constant considering the output of decision device (sliced symbol) in order to updating the tap coefficients. By using the two kind error signal, the adaptive equalization algorithm has different performance. In this paper, we compare to the adaptive equalization algorithm performance by using the recovered constellation, residual isi, MD (Maximum Distortion) and SER as a index when the transmitting signal is 16 and 64-QAM and then passing through the same communication channel. As a result of simulation, the S-MMA can improving the Roburstness in SER performance compared to the MMA in the high order QAM signal.

본 논문에서는 시분산 채널에서 발생되는 진폭과 위상 찌그러짐을 동시에 보상할 수 있는 적응 등화 알고리즘인 MMA (Multiple Modulus Algorithm)와 S-MMA (Sliced-MMA)의 성능을 비교하였다. 기존 CMA 알고리즘은 진폭만을 복원하며 위상의 복원이 불가능하므로 이를 위해 별도의 부가 회로가 필요케 되는 단점을 극복하기 위해 MMA 알고리즘에서는 개선된 비용 함수를 적용하였다. MMA 알고리즘에서는 탭 계수의 갱신을 위해 dispersion constant를 이용한 오차를 표현하고, S-MMA에서는 결정 장치의 출력 (Sliced-Symbol)을 고려한 dispersion constant를 이용한 오차를 표현하게 되어, 이와 같은 오차 신호의 차이로 인하여 적응 등화 알고리즘은 서로 상이한 성능을 갖게 된다. 논문에서 QAM 신호의 차수를 16과 64로 한 후 동일 채널을 통과하여 신호를 수신할 때 이들 적응 등화 알고리즘의 성능을 나타내는 지수로 복원 성상도, 잔류 isi, MD 및 SER을 적용하여 비교한다. 시뮬레이션 결과 S-MMA가 QAM의 차수가 높을수록 MMA보다 SER 성능이 개선으로 Roburstness가 개선됨을 확인하였다.

Keywords

References

  1. J.Yang, J.J.Werner, G.A.Dumont, "The Multimodulus Blind Equalization and Its Generalized Algorithms", IEEE Journal on S.A. in Comm., Vol.20, No.5, pp. 997-1015, June 2002 https://doi.org/10.1109/JSAC.2002.1007381
  2. J.Yang, J.J.Werner, G.A.Dumont, "The Multimodulus Multi-modulus Blind Equalization Algorithm", 13th Int. Conf. D.S.P. Processing, pp.127-130, 1997
  3. S.A.Sheikh, P.Fan, "A New Multimodulus Blind Equalizer for Dense QAM Constellation", Int. Conf. on Wireless, Mobile & Multimedia Network, pp.1-4, 2006
  4. S.Abrar, R.A.Axford, "Sliced Multi-modulus Blind Equalization Algorithm", ETRI Journal, Vol.27, No.3, pp.257-266, June 2005 https://doi.org/10.4218/etrij.05.0104.0027
  5. S.G.Lim, "The Performance Comparison of the CMA and MMA Algorithm for Blind Adaptive Equalization", Journal of I.W.I.T., Vol.12, No.2, pp.153-158, 2012
  6. S.G.Lim, "The Performance Comparison of the MMA and SCA Algorithm for Self Adaptive Equalization", Journal of I.W.I.T., Vol.12, No.2, pp.159-165, April 2012
  7. R.A.Axford Jr., L.B.Milstein, J.R.Zeidler, "The Transversal and Lattice Multiple Modulus Algorithms for Blind Equalization Of QAM Signals", Proc. IEEE MILCOM'95, pp.586-591, Vol.2, Nov. 1995
  8. W.A.Sethares, G.A.Rey, C.R.Johnson, "Approaches to Blind Equalization of Signals with Multiple Modulus", Proc. IEEE ICASSP, pp.972-975, 1989

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