Improved Robust Multiuser Detection in Flat Fading Synchronous Non-Gaussian Channels using Chaotic Spreading

Code-division multiple-access (CDMA) transmissions are made frequently over fading channels. Robust multiuser detection is known in the literature for suppression of multi access interference (MAI) and impulse noise in CDMA communications. However, the performance of the robust multiuser detector depends on the selection of M- estimator and the spreading sequence. Thus, the detector proposed in [5] with Huber M-estimator and PN sequence such as Gold sequence spreading may not yield optimal performance for highly impulsive noise. A new M-estimator- based structure using spatiotemporal chaotic spreading sequences for noncoherent demodulation of differentially phase-shift keyed (DPSK) signals transmitted simultaneously via a synchronous CDMA flat-fading channel and embedded in impulsive noise, is proposed. Simulation results demonstrate that the proposed detector using spatiotemporal chaotic spreading offers significant performance gain as compared to detectors with gold sequences as spreading sequences.