Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Performance Comparison of Step-Size Update Methods for Modified CMA

변형된 CMA의 수렴상수 갱신 방법의 성능 비교

  • Oh, Kil-Nam (Dept. of Optical Communications Engineering, Gwangju University)
  • 오길남 (광주대학교 광통신공학과)
  • Received : 2011.07.25
  • Accepted : 2011.09.08
  • Published : 2011.09.30
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Abstract

Compared to the constant modulus algorithm (CMA), the modified CMA (MCMA) is easy not only to improve the steady-state performance but also to be expanded to higher-order constellations by using fewer moduli with evenly spaced. In this paper, it is shown that the MCMA is sufficient to achieve satisfactory steady-state performance by applying a variable step-size to the MCMA without switching to an hard decision-directed algorithm. Two new methods varying the step-size are proposed, and the performance improvement of the MCMA with the new methods of variable step-size is presented as compared to the CMA and the fixed step-size MCMA through computer simulations.

변형된 CMA는 CMA에 비해 고차 신호점을 등화 시 보다 적은 수의, 균등한 간격을 갖는 모듈러스를 이용함으로써 정상상태 성능 개선과 고차 신호점으로의 확장이 용이하다. 본 논문에서는 변형된 CMA에 가변 수렴상수를 적용하여 정상상태 성능을 더욱 개선하여 다른 경판정 알고리즘으로의 전환 없이도 충분히 만족스러운 성능을 달성할 수 있음을 보인다. 새로운 두 가지 수렴상수 가변 방법을 제안하고, 이를 적용한 변형된 CMA의 성능 개선을 모의실험을 통해 CMA와 고정 수렴상수의 변형된 CMA에 대해 확인하였다.

Keywords

References

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