Robust channel estimation and multiuser detection for MC-CDMA systems under narrowband interference

In this paper, we present a robust multiuser detector for wireless multicarrier code-division multiple access (MC-CDMA) systems under time-varying narrowband interference (NBI). The conventional least-squares (LS) channel estimators and multiuser detectors will perform poorly when narrowband interfering signals contaminate the multicarrier systems. A new weighted least M-estimate (WLM) multiuser detector is proposed to jointly suppress multiple access interference (MAI) and time-varying NBI. The WLM multiuser detector resorts to M-estimate and weighted least-squares (WLS) techniques. A weighted recursive least M-estimate (WRLM) channel estimator is exploited to estimate the time-varying frequency-selective fading channels in the presence of NBI. Numerical results show that the proposed WLM multiuser detector significantly outperforms over the conventional linear decorrelator, the robust decorrelating detector with M-estimate and the WLS detector under NBI