Performance Comparison on Non-linear Distortion for MC-CDMA and MC-DS/CDMA System in Mobile Satellite Quasi-synchronous Return Link

이동 위성 준동기 리턴링크에서 MC-CDMA와 MC-DS/CDMA 시스템의 비선형 왜곡에 대한 성능 비교 분석

  • 안치훈 (연세대학교 전기전자공학과) ;
  • 최영관 (연세대학교 전기전자공학과) ;
  • 이호진 (연세대학교 전기전자공학과) ;
  • 김동구 (연세대학교 전기전자공학과)
  • Published : 2003.03.01

Abstract

We analyze the performances of MC-CDMA and MC-DS/CDMA systems on quasi-synchronized mobile satellite return link. Quasi-synchronization is considered that chip offset between user terminals is within a few chips. Since the transmitted signals of MC-CDMA and MC-DS/CDMA systems have non-constant envelop, they are easily distorted by nonlinearity of transmit amplifier. Since the nonlinear amplifier input signal level of MC-CDMA system using Walsh code to employ frequency domain spreading is lower than that of MC-DS/CDMA system, performance of single user in MC-CDMA system is respectively 2.3dB and 1dB better than that of MC-DS/CDMA system when amplifier input backoff is 0dB and 6dB. However, since interference of MC-DS/CDMA is less than that of MC-CDMA with many subcarriers in quasi-synchronization and AWGN channel, MC-DS/CDMA system is much better than MC-CDMA system as the number of users increases.

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