An Efficient Algorithm Assisted Minimum Bit Error Rate Multiuser Detector for DS-CDMA Systems in Time-Varying and Frequency-Selective Fading Channels

Zeybek M., ERTUĞ Ö.

4th International Congress on Ultra Modern Telecommunications and Control Systems (ICUMT), St Petersburg, Russia, 3 - 05 October 2012, pp.154-161, (Full Text) identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume:
  • Doi Number: 10.1109/icumt.2012.6459656
  • City: St Petersburg
  • Country: Russia
  • Page Numbers: pp.154-161
  • Gazi University Affiliated: Yes

Abstract

A minimum bit error rate (MBER) multiuscr detector (MUD) is considered for Direct-Sequence Code-Division Multiple-Access (DS-CDMA) communication systems with time-varying and frequency-selective fading channels. The BER cost function of the proposed MBER MUD is highly non-linear and may have several local minimum. It is shown that with some appropriate constraints the BER cost function of the MBER MUD is equivalent to a constrained optimization problem which has a unique global minimum in the feasible region. An efficient Newton method with a barrier parameter is developed for finding the coefficients of the proposed MBER MUD. The BER performance of the MBER MUD is compared to decorrelating (DEC) detector, linear minimum mean-square error (LMMSE) detector, and the maximum likelihood detector for time varying and Rayleigh distributed frequency-selective fading DS-CDMA channels. Monte-Carlo simulations show that the BER of the MBER MUD can be significantly lower than that of the DEC and the LMMSE multiuser detectors.