CHAOTIC COMPLEX SPREADING SEQUENCES FOR ASYNCHRONOUS DS-CDMA - PART-II - SOME THEORETICAL PERFORMANCE BOUNDS

This paper and its companion (Part I) are devoted to the evaluation of the impact of chaos-based techniques on communications systems with a synchronous Code Division Multiple Access. In Part I, a performance in dex was introduced and exploited to a priori estimate the performance of DS-CDMA communications systems based on chaotic spreading sequences , and to compare it to that of conventional systems, Here, tools from nonlinear dynamical system theory are employed to give a formal ground for those results. Analytical bounds on the expected partial cross co rrelation between spreading sequences obtained by quantizing and repea ting a chaotic time series are derived, ensuring general applicability of such a technique in a real environment. Further analytical argumen ts guarantee that, when particular chaotic generators are used, expect ed performance is not worse than that of a well-behaving communication s system. This analysis ensures also that, unlike conventional sequenc es, chaotic spreading codes can be generated for any number of users a nd allocated bandwidth.