Abstract:

To reduce distortion due to AWGN（Additive White Gaussian Noise） in transmission channel of DCSK(Differential Chaos Shift Keying) chaotic communication system, an improved system scheme was proposed Which is called PIDCSK（Phase Inversion Differential Chaos Shift Keying） chaotic communication system based on DCSK modulation system. According to the delay retransmission mechanism of information signal and reference signal had a
halfsymbol period delay at the transmitter in the DCSK system; then at the PIDCSK receiver the phase inversion correlated demodulation during halfsymbol period for received signal was exploited. By the fact that the adjacent noises within a symbol period in the channel was correlated, the proposed scheme could reduce the adjacent noise interference obviously and further decrease the bit error rate of DCSK modulation system with the same SNR（Signal to Noise Ratio）. Simulation results show that PIDCSK system performance is better than DCSK system, especially in larger correlation coefficient, and the lower SNR condition.

Key words: chaotic communication, phase inversion differential chaos shift keying（PI-DCSK）, phase inversion, correlation coefficient, bit error ratio（BER）