A Constant Modulus Algorithm (CMA) for Blind Acoustic Communication Channel Equalization with Improved Convergence Using Switching between Projected CMA and Algebraic Step Size CMA

Jun-Seok Lim; Yong-Guk Pyeon

doi:10.7776/ASK.2015.34.5.394

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A Constant Modulus Algorithm (CMA) for Blind Acoustic Communication Channel Equalization with Improved Convergence Using Switching between Projected CMA and Algebraic Step Size CMA 직교 정사영 CMA와 대수학적 스텝 사이즈 CMA 간 스위칭 방법을 통해 개선된 수렴성을 갖는 CMA형 블라인드 음향 통신 채널 등화기 연구

30 September 2015. pp. 394-402

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Abstract

CMA (Constant Modulus Algorithm) is one of the well-known algorithms in blind acoustic channel equalization. Generally, CMA converges slowly and the speed of convergence is dependent on a step-size in the CMA procedure. Many researches have tried to speed up the convergence speed by applying a variable step-size to CMA, e.g. the orthogonal projection CMA and algebraic optimal step-size CMA. In this paper, we summarize these two algorithms, and we propose a new CMA with improved convergence performance. The improvement comes from the switching between the orthogonal projection CMA and algebraic optimal step-size CMA. In simulation results, we show the performance improvement in the time invariant channels as well as in time varying channel.

Keywords

Acoustic communication

Channel equalization

High speed convergence

Blind equalization

Acoustic communication

음향 통신용 등화기 기술 중에서, 훈련 신호를 사용하지 않는 블라인드 채널 등화기의 일종인 Constant Modulus Algorithm(CMA)방식 등화기의 수렴 속도는 일반적인 훈련 신호를 사용하는 비블라인드 방법에 비해서 느린 경향이 있다. 이런 느린 수렴 속도를 향상 시키기 위한 방법으로는 직교 정사영 망각인자를 도입한 직교 정사영 CMA와 대수적인 방법으로 스텝 사이즈를 계산하는 대수학적 스텝 사이즈 CMA 등이 제안되어 있다. 이들 두 방법 모두 수렴 속도를 향상시키지만 경우에 따라서 성능이 기대에 못 미치는 결과가 발생하기도 한다. 본 논문에서는 직교 정사영 CMA와 대수학적 스텝 사이즈 CMA를 각각 요약 설명 하고, 이 각각을 스위칭을 이용하여 결합하는 방법을 제안한다. 그리고 시뮬레이션을 통해서 여러 시불변 채널과 시변 채널에 대해서 그 수렴 성능이 개선됨을 보인다.

키워드

음향 통신

채널 등화기

고속수렴

블라인드 등화기

직교 정사영 CMA

대수학적 스텝 사이즈 CMA

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 34
No :5
Pages :394-402
Received Date : 2015-06-05
Revised Date : 2015-07-10
Accepted Date : 2015-07-27
DOI :https://doi.org/10.7776/ASK.2015.34.5.394

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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