Chaotic complex spreading sequences for asynchronous DS-CDMA-Part I: System modeling and results

Abstract— This paper and its companion are devoted to the evaluation of the impact of chaos-based techniques on communi- cations systems with asynchronous code division multiple access. Sequences obtained by repeating a truncated and quantized chaotic time series are compared with classical -sequences and Gold sequences by means of a performance index taken from communication theory which is here defined and thoroughly dis- cussed. This analysis reveals that, unlike conventional sequences, chaotic spreading codes can be generated for any number of users and allocated bandwidth. Numerical simulations are reported, showing that systems based on chaotic spreading sequences per- form generally better than the conventional ones. Some analytical tools easing the comprehension of these advantages are here summarized and proved in Part II where formal arguments are developed and discussed to ensure general applicability of chaotic spreading codes.