Abstract: A new kind of differential chaos keying communication system was presented based on repeated spreading sequence(RSS). Bit error rate(BER) performance is theortically analyzed and then verified by numerical simulations. In the proposed system, a repeated spreading sequence is produced by copying the reference sequence of the DCSK-modulated signal, and part of the parallel bit streams are multipled with this RSS and the resulting signals are then conveyed into the channel. Theoretical analysis and simulation results show that the BER performance of this system is better than DCSK、CDSK and CD-DCSK. And this system performs better when the spreading factor reduces. The BER performance over the AWGN channel is better than the performance over Rayleigh channel.

Key words: chaos secure communication, differential chaos shift keying, chaos spread sequence