Improving the performance of turbo code by optimizing QAM constellation points

QAM 변조방식의 성상도 최적화를 통한 터보 부호의 성능 개선 연구

  • 이근형 (충남대학교 정보통신공학과) ;
  • 강동훈 (충남대학교 정보통신공학과) ;
  • 이지연 (충남대학교 정보통신공학과) ;
  • 오왕록 (충남대학교 전기정보통신공학부)
  • Published : 2009.05.07

Abstract

It is well-known that the performance of turbo codes can be improved by allocating different energies per code symbol. In this paper, based on this observation, we propose a joint encoding and modulation scheme for quadrature amplitude modulated turbo code systems. In the proposed scheme, the amount of energy difference between the turbo coded symbols is optimized by optimizing the constellation of quadrature amplitude modulation(QAM). The proposed scheme offers better coding gain compared to the conventional combination of binary turbo code and QAM at the bit error rate of $10^{-5}$.

Keywords