Near-far resistant detection of symbol and chip-timing error in asynchronous DS/CDMA communication system

This paper presents a DS/CDMA multiuser demodulator, which has near-far resistance in both the symbol and chip-timing error detection. The key point is that the symbol detector and the chip timing error detector employ the same linear decorrelating detector using the same inverse cross-correlation matrix. To facilitate digital implementation and take the effects of band limitation into account, the decorrelating detector uses multiple correlators for each of the interfering users, which consist of successively rotated versions of the original PN sequence for that user. Simulation results show superior performance of the proposed detector in both the symbol and the chip-timing error detection over the conventional demodulator.