Chaotic Spread-Spectrum Communication: A Comparative Study between Chaotic Synchronization and Matched Filtering

Abstract

This publication investigates the performance of demodulation methods utilized in spread spectrum chaotic communication systems, specifically matched filtering and chaotic synchronization. We conduct simulations and comparisons of three different communication systems: classic direct sequence spread spectrum (DSSS), chaotic signal fragment-based pseudo-chaotic spread spectrum (PCSS), and chaotic synchronization-based antipodal chaos shift keying (ACSK). These systems possess similar spectral and time domain characteristics, allowing us to shed light on their fundamental differences and limitations. Additionally, we assess the impact of frequency modulation (FM) on these modulation methods, as FM allows the creation of simplified non-coherent modulation schemes. Our findings, based on the analysis of bit error ratio (BER) curves, clearly demonstrate that the utilization of quantized waveforms for spreading confers a significant advantage over analogous, continuous-time spread spectrum systems. In addition, it is shown that the employment of chaotic synchronization instead of cross-correlation does not degrade the performance of the communication system and provides a more secure approach. In general, this research aims to enhance awareness regarding the distinct advantages and limitations associated with chaotic spread spectrum modulation methods.