DS-CDMA commutation signalling with frequency offsets for wireless communications

Commutation signalling is an antimultipath technique that uses direct-sequence spreading for combatting multipath induced ISI. We propose a CDMA-like multiple-access scheme that utilizes this inherent spreading. Since the processing gains involved in such systems are small, multiple users employ different carrier frequencies for reducing the interference. The performance measure used is the variance of the interference as a function of the frequency offset between users. We consider the performance with different chip pulses and compare deterministic spreading sequences with random spreading sequences