Performance of adaptive iterative multiuser parallel decision feedback with different code rates

G. Woodward*, M. L. Honig

*Corresponding author for this work

Research output: Contribution to journalConference article

8 Scopus citations

Abstract

An adaptive receiver which combines multiuser Parallel Decision-Feedback with MAP decoding in an iterative manner is presented for synchronous coded DS-CDMA. Performance with various convolutional code rates is considered. Optimal filters are derived using both Minimum Mean Squared Error (MMSE) and Least Squares (LS) criteria. When used with short (repeated) spreading codes, the adaptive LS receiver requires only a training sequence and timing for estimation of all filter coefficients. The adaptive receiver performs significantly better than the standard (soft) interference canceller, since the adaptive algorithm attempts to measure and exploit the joint statistics of the output of the MAP decoder with the input symbols. Numerical results are presented which illustrate how performance depends on the rate of the convolutional code, assuming similar decoding complexity. These results show that low code rates perform best at moderate loads and low received power. Higher code rates can achieve very low packe t error rates for an overloaded system (number of users greater than the bandwidth expansion).

Original languageEnglish (US)
Pages (from-to)852-856
Number of pages5
JournalIEEE International Conference on Communications
Volume3
StatePublished - Jan 1 2001
EventInternational Conference on Communications (ICC2001) - Helsinki, Finland
Duration: Jun 11 2000Jun 14 2000

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering

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