Co-Existence of Chaos-Based Communication Systems and Conventional Spread-Spectrum Communication Systems

This paper studies the performance of selected chaos-based systems which share their frequency bands with conventional spread-spectrum systems. Such a scenario may occur in normal practice when chaos-based systems are introduced while the conventional systems are still in operation. The particular chaos-based systems under study are the coherent chaosshift-keying (CSK) system and the non-coherent differential CSK system, and the co-existing conventional system employs the standard direct-sequence spread-spectrum modulation scheme. Analytical expressions for the bit error rates are derived and computer simulations are performed to verify the analytical findings. Index Terms — Chaos communication, chaos-shift-keying, differential chaos-shift-keying, direct-sequence spread-spectrum.