한국전자파학회논문지 (The Journal of Korean Institute of Electromagnetic Engineering and Science)

  • 제23권1호
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  • Pages.38-46
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  • 2012
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  • 1226-3133(pISSN)
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  • 2288-226X(eISSN)
한국전자파학회 (The Korean Institute of Electromagnetic Engineering and Science)
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고속 처리와 성능 향상을 위한 LDPC 코드 기반 결정 궤환 등화기

Decision Feedback Equalizer Based on LDPC Code for Fast Processing and Performance Improvement

  • Kim, Do-Hoon (Department of Electronic Engineering, Chungbuk National University) ;
  • Choi, Jin-Kyu (Department of Electronic Engineering, Chungbuk National University) ;
  • Ryu, Heung-Gyoon (Department of Electronic Engineering, Chungbuk National University)
  • 투고 : 2011.11.16
  • 심사 : 2011.11.23
  • 발행 : 2012.01.31
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초록

본 논문에서는 OFDM 시스템에서 고속 처리와 성능 향상을 위한 LDPC 코드 기반 결정 궤환 등화기(Decision Feedback Equalizer: DFE)를 제안한다. LDPC 코드는 우수한 오류 정정 능력과 Shannon의 채널 용량에 근접하는 성능을 갖는다. 그러나, 많은 parity 검사 행렬과 반복 횟수를 가진다는 단점이 있다. 제안된 시스템에서는 판정된 신호와 복호기 사이의 신호의 MSE(Mean Square Error)를 등화기로 피드백한다. 이러한 방법을 사용하면 추정된 채널 응답을 보정해 주기 때문에 성능을 향상시킬 수 있다. 또한, 동일한 성능에서 피드백이 포함되지 않은 시스템보다 낮은 반복 횟수를 갖기 때문에 시스템의 복잡도를 줄일 수 있다. 시뮬레이션을 통해 다중 경로 채널에서 CFO(Carrier Frequency Offset)와 위상 잡음이 고려된 OFDM 시스템의 성능을 평가하여 제안 시스템의 우수성을 보인다.

In this paper, we propose a decision feedback equalizer based on LDPC(Low Density Parity Check) code for the fast processing and performance improvement in OFDM system. LDPC code has good error correcting capability and its performance approaches the Shannon capacity limit. However, it has longer parity check matrix and needs more iteration numbers. In our proposed system, MSE(Mean Square Error) of signal between decision device and decoder is fed back to equalizer. This proposed system can improve BER performance because it corrects estimated channel response more accurately. In addition, the proposed system can reduce complexity because it has a lower number of iterations than system without feedback at the same performance. Simulation results evaluate and show the performance of OFDM system with the CFO and phase noise in multipath channel.

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참고문헌

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