Joint frequency-domain differential detection and equalization for DS-CDMA signal transmissions in a frequency-selective fading channel

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

It has been revealed that direct sequence code-division multiple access (DS-CDMA) can achieve a good bit-error rate (BER) performance, comparable to multicarrier CDMA (MC-CDMA), by using coherent frequency-domain equalization (FDE) instead of coherent Rake combining. However, coherent FDE requires accurate channel estimation. Pilot-assisted channel estimation is a practical solution, but its accuracy is sensitive to the Doppler spread. In this paper, a frequency-domain differential encoding and detection scheme is proposed for a DS-CDMA mobile radio. Joint frequency-domain differential detection and equalization (FDDDE) based on minimum mean-square error (MMSE) criterion is presented, where a simple decision feedback filter is used to provide a reliable reference signal for MMSE-FDDDE. Also presented is an approximate BER analysis. It is confirmed by both approximate BER analysis and computer simulation that MMSE-FDDDE provides good BER performance close to the coherent MMSE-FDE and shows high robustness against the Doppler spread; it outperforms coherent MMSE-FDE for large Doppler spreads. The proposed MMSE-FDDDE can also be applied to MC-CDMA. A performance comparison between uncoded DS- and MC-CDMA shows that DS-CDMA with MMSE-FDDDE achieves better BER performance than MC-CDMA with MMSE-FDDDE for small spreading factors.

Original languageEnglish
Pages (from-to)649-658
Number of pages10
JournalIEEE Journal on Selected Areas in Communications
Volume24
Issue number3
DOIs
Publication statusPublished - 2006 Mar

Keywords

  • Direct sequence code-division multiple access (DS-CDMA)
  • Frequency-domain differential detection (FDDD)
  • Frequency-domain equalization (FDE)

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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