Performance comparison of turbo-coded DS-CDMA, MC-CDMA and OFDM with frequency-domain equalization and higher-level modulation

Deepshikha Garg, Fumiyuki Adachi

Research output: Contribution to journalConference articlepeer-review

6 Citations (Scopus)

Abstract

For high-speed data communications, channel coding and high-level modulation will be inevitable. In this paper, we compare the turbo coded performances of DS-CDMA and MC-CDMA which are the major contenders for next generation wireless signaling technique. Minimum mean square frequency-domain equalization (MMSE-FDE) is assumed for both DS-CDMA and MC-CDMA. The log-likelihood ratio (LLR) computation is used to generate the soft decision value needed for turbo decoding. It is found that the DS-CDMA performance is the same for all spreading factor (SF) and equivalent to a fully spread MC-CDMA for all modulation levels and coding rates. For an uncoded system, DS-CDMA is better than MC-CDMA for smaller SF due to a larger frequency diversity gain. However, with turbo coding, MC-CDMA with smaller SF provides better performance due to larger coding gain owing to better frequency interleaving and severe orthogonality destruction for larger SF and DS-CDMA wherein a symbol is spread over the entire bandwidth.

Original languageEnglish
Pages (from-to)2282-2286
Number of pages5
JournalIEEE Vehicular Technology Conference
Volume60
Issue number3
Publication statusPublished - 2004 Dec 1
Event2004 IEEE 60th Vehicular Technology Conference, VTC2004-Fall: Wireless Technologies for Global Security - Los Angeles, CA, United States
Duration: 2004 Sep 262004 Sep 29

Keywords

  • DS-CDMA
  • MC-CDMA
  • MMSE-FDE
  • MQAM
  • Turbo coding

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics

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