Prototyping of a Pass-Band Chaos-Based CDMA System in FPGA Technology

This paper presents the theoretical analysis, design and FPGA implementation of a pass-band chaos-based CDMA system. The system uses a digital modulation technique called Chaos-Phase-Shift-Keying (CPSK) in a complex form, where chaotic sequences are used for spreading digital messages. Conventional multi-rate signal processing techniques are employed for carrier modulation and demodulation, which changed the structure of the theoretical model of the analysed system. The model of a pass-band additive white Gaussian noise channel is also constructed. The system is implemented in Altera Stratix II EP2S180 DSP Development Board. The FPGA design flow is carried out using Alter DSP Builder integrated into MathWorks Simulink algorithm development environment. The BER characteristics obtained on the prototype and simulation confirmed the theoretical findings.