We have proposed a new M-estimator based structure for noncoherent demodulation of differentially phase-shift keyed (DPSK) signals transmitted simultaneously via direct sequence code division multiple access (CDMA) flat-fading channel and embedded in impulsive noise. The approach is also corroborated with simulation results to show the efficacy of the proposed detector with the proposed M-estimator in synchronous flat-fading non-Gaussian channels. The gross error sensitivity for the proposed estimator is analyzed. Further, lower bounds for the explosion and implosion breakdown points of the proposed estimator are derived.

This paper presents a robust multiuser detector for combating multiple access interference and impulsive noise in direct-sequence code-division multiple-access (DS-CDMA) communication systems. A new M-estimator is proposed for robustifying the detector. The lower bounds for the explosion and implosion breakdown points of the proposed estimator are derived. For appropriate tuning constants, it is shown that the breakdown points attain the maximum possible value. The approach is also corroborated with simulation results to evaluate the performance of the proposed robust multiuser detector in comparison with the linear decorrelating detector, Huber and Hampel M-estimator based detectors. Simulation results show that, in highly impulsive noise, the proposed detector with the proposed M-estimator with significant performance gain outperforms the linear decorrelating detector, Huber and Hampel M-estimator based detectors in both synchronous and asynchronous non-Gaussian channels.