대한전자공학회논문지SP (Journal of the Institute of Electronics Engineers of Korea SP)

대한전자공학회 (The Institute of Electronics and Information Engineers)
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블라인드 채널 등화를 위한 교번 적응 알고리즘

Alternate Adaptation Algorithm for Blind Channel Equalization

  • 오길남 (광주대학교 광통신공학과)
  • Oh, Kil-Nam (Dept. of Optical Communications Engineering, Gwangju University)
  • 투고 : 2010.11.08
  • 심사 : 2011.05.09
  • 발행 : 2011.07.25
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초록

CMA(constant modulus algorithm)의 수렴 특성과 정상상태 성능을 개선하기 위한 교번 적응 알고리즘(alternate adaptation algorithm: AAA)을 제안한다. 교번 적응 알고리즘은 블라인드 수렴 특성이 우수한 알고리즘과 정상상태 오차 성능이 좋은 알고리즘을 이용하여 등화기를 번갈아 적응시키는 새로운 등화 방법이다. 본 논문에서는 가변 수렴상수를 적용한 vsCMA(variable step-size CMA)와 판정의거(decision-directed: DD) 알고리즘을 이용한 교번 적응 등화를 소개한다. 제안 방식에서는 먼저, CMA의 정상상태 오차 성능 개선을 위해 수렴상수를 가변 하는 vsCMA를 고안하였으며, 이를 DD와 교번 적응에 의해 결합함으로써 CMA의 수렴 속도와 정상상태 성능을 개선하고, CMA-DD 전환 방식에서 전환 타이밍에 따른 성능 변동의 민감성을 완화하였다. 제안 방법의 유용성을 확인하기 위해 컴퓨터 모의실험을 통해 다중경로 채널에서 16-QAM에 대해 평가하였다.

The alternate adaptation algorithm (AAA) is proposed to improve the convergence characteristics and steady-state performance of the constant modulus algorithm (CMA). The alternate adaptation algorithm is a new equalization method which adapts an equalizer alternately by the algorithm with excellent blind convergence characteristics or the algorithm with better steady-state error performance. In this paper, it is introduced that the alternate adaptation equalization of the vsCMA (variable step-size CMA) and the decision-directed (DD) algorithm. We, first, designed the vsCMA with variable step-size to improve the steady-state error performance of the CMA, and combined it with the DD by alternate adaptation. As a result, it was mitigated that the sensitivity of performance fluctuation due to switching timing in CMA-DD switching method, and it was improved that the convergence speed and steady-state error performance of the CMA. Through computer simulations, under multipath channel condition, the usefulness of the proposed method was confirmed for 16-QAM.

키워드

참고문헌

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