A new signature sequence scheme for CDMA with good mean-square correlation properties

In this paper, we propose and investigate a new signature sequence scheme for asynchronous direct-sequence code-division multiple-access (DS-CDMA) communication systems. The new sequence set offers good mean-square cross-correlation (MSCC) properties in both even and odd correlation functions, which are important for system capacity, acquisition and demodulation performance in DS-CDMA systems. A new asynchronous phase-coded DS-CDMA system model is proposed. An analysis of the new system model is presented, and a new aperiodic cross correlation function is derived. The correlation properties of the new sequence set are presented and compared with those of the conventional PN sequence sets. Emphasis is placed on the average rather than the worst case performance. Numerical results show that MSCC value of the new sequence set is only about half of those of the conventional PN sequence sets. This may result in an improvement of 3 dB in the multiple access interference (MAI) performance