한국정보통신학회논문지 (Journal of the Korea Institute of Information and Communication Engineering)

  • 제22권2호
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  • Pages.253-260
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  • 2018
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  • 2234-4772(pISSN)
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  • 2288-4165(eISSN)
한국정보통신학회 (The Korea Institute of Information and Commucation Engineering)
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천해환경에서 적응 알고리즘을 이용한 음향 등화기의 성능 비교

Performance Comparison of Acoustic Equalizers using Adaptive Algorithms in Shallow Water Condition

  • Chuai, Ming (Dept. of Information and Communications Engineering, Pukyong National University) ;
  • Park, Kyu-Chil (Dept. of Information and Communications Engineering, Pukyong National University)
  • 투고 : 2018.01.19
  • 심사 : 2018.01.29
  • 발행 : 2018.02.28
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초록

천해 환경에서의 수중 음향 통신 채널은 전형적으로 시변 다중 경로 페이딩 채널 특성을 나타낸다. 이러한 채널 전송을 통해 수신된 신호는 시간 지연 및 진폭의 중첩에 의해 심볼 간 간섭을 유발한다. 이를 보완하기 위해 여러 기술이 사용되었으며, 그 중 하나가 음향 등화기이다. 본 연구에서는 심볼 간 간섭을 보상하기 위해 feed-forward equalizer (FFE), decision direct equalizer (DDE), decision feedback equalizer (DFE) 및 DFE와 결합된 DDE의 4 종류의 등화기와 등화기의 계수를 조정하기 위해 normalized least mean square (NLMS) 알고리즘과 recursive least square (RLS) 알고리즘의 2 종류의 알고리즘을 적용하였다. 그 결과 비선형 등화기에서는 신호 대 잡음비 6 dB 이상에서 상당한 성능 향상을 발견할 수 있었으며, DFE와 DDE의 조합은 어떤 경우에도 최고의 성능을 발휘하였다.

The acoustic communication channel in shallow underwater is typically shown as time-varying multipath fading channel characteristics. The received signal through channel transmission cause inter-symbol interference (ISI) owing to multiple components of different time delay and amplitude. To compensate for this, several techniques have been used, and one of them is acoustic equalizer. In this study, we used four equalizers - feed forward equalizer (FFE), decision directed equalizer (DDE), decision feedback equalizer (DFE) and combination DDE with DFE to compensate ISI. And we applied two adaptive algorithms to adjust coefficient of equalizers - normalized least mean square algorithm and recursive least square algorithm. As result, we found that it has a significant performance improvement over 6 dB on SNR in nonlinear equalizer. By combination of DFE and DDE has almost best performance in any case.

키워드

참고문헌

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