This paper investigates the chaos-based asynchronous direct sequence code-division multiple access (DS-CDMA) system performance optimization in accordance with spreading sequences set. The multiple access interference (MAI) power is estimated for conventional matched-filter receiver scheme, under the standard gaussian approximation (SGA) hypothesis, and minimized with respect to the auto-correlation function of the spreading sequences. The well-known family of optimum autocorrelation chaotic spreading sequences generated by the (n, t) – tailed shifts map is reconsidered. The present work intends to prove that not only binary quantized sequences are optimum, but also for any number of levels an optimum of the autocorrelation function exists.

Keywords: Chaos-based communications systems, DS-CDMA, Performance optimization, MAI, Quantized chaotic trajectories.