Time-frequency decorrelating decision-feedback multiuser detector over fast-fading multipath channels for synchronous DS-CDMA systems

ERTUĞ Ö., BAYKAL B.

3rd IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2001, T'ao-yuan, Tayvan, 20 - 23 Mart 2001, cilt.2001-January, ss.170-173 identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Cilt numarası: 2001-January
  • Doi Numarası: 10.1109/spawc.2001.923874
  • Basıldığı Şehir: T'ao-yuan
  • Basıldığı Ülke: Tayvan
  • Sayfa Sayıları: ss.170-173
  • Anahtar Kelimeler: Channel estimation, Code division multiplexing, Decorrelation, Degradation, Detectors, Fading, Frequency diversity, Multipath channels, Scattering, Time frequency analysis
  • Gazi Üniversitesi Adresli: Evet

Özet

RAKE receivers suffer degradation in performance under fast fading due to errors in channel state estimation. The wide-sense stationary uncorrelated scatterer channel model lends itself to a time-frequency canonical representation, and provides additional diversity in the frequency axis. Using the joint multipath-Doppler diversity model based on this canonical representation, we propose a nonlinear time-frequency decorrelating decision-feedback multiuser detector for synchronous CDMA which utilizes decisions of the stronger users when forming the decisions for the weaker ones. Analytical and simulation results based on realistic fast-fading assumptions demonstrate that the proposed decision-feedback multiuser detector promises substantially improved bit-error-rate performance compared to the time-frequency decorrelating multiuser detector for the weaker users, while the error probability of the weakest user approaches the single-user bound as the interferers grow stronger. The proposed detector exhibits strong resistance to the near-far effect for all users and the time complexity per bit is linear in the number of users.