The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Bit-to-Symbol Mapping Strategy for LDPC-Coded Turbo Equalizers Over High Order Modulations

LDPC 부호 기반의 터보 등화기에 적합한 고차 변조 심볼사상

  • 이명규 (포항공과대학교 전자전기공학과 통신 및 신호설계 연구실) ;
  • 양경철 (포항공과대학교 전자전기공학과 통신 및 신호설계 연구실)
  • Received : 2009.05.30
  • Accepted : 2010.03.08
  • Published : 2010.05.31
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Abstract

In this paper we study the effect of bit-to-symbol mappings on the convergence behavior of turbo equalizers employing low-density parity-check (LDPC) codes over high order modulations. We analyze the effective SNR of the outputs from linear minimum mean-squared error (MMSE) equalizers and the convergence property of LDPC decoding for different symbol mappings. Numerical results show that the bit-reliability (BR) mapping provides better performance than random mapping in LDPC-coded turbo equalizers over high order modulations. We also verify the effect of symbol mappings through the noise threshold and error performance.

본 논문에서는 고차 변조 방식의 심볼 사상(mapping)이 LDPC (low-density parity-check) 부호를 사용하는 터보 등화기(turbo equalizer)의 수렴 특성에 미치는 영향에 대해서 살펴본다. 심볼 사상에 따른 선형 MMSE 등화기의 유효(effective) SNR과 LDPC 복호기의 수렴 특성을 통해 LDPC 부호를 사용하는 터보 등화기에 BR (bit-reliability) 사상이 성능 관점에서 유리하다는 것을 보여준다. 그리고 밀도 진화 분석(density evolution)을 통한 잡음 임계치(noise threshold)와 전산 실험 결과를 통해 터보 등화기의 성능에 심볼 사상이 미치는 영향을 검증한다.

Keywords

References

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