NR-MC-CDSK Chaotic Communication System Based on Schmidt Orthogonalization

In order to solve the shortcomings of high Bit Error Rate (BER) in traditional Correlation Delay Shift Keying (CDSK) chaotic communication system, a Noise Reduction Multi-Carrier Correlated Delay Shift Keying (NR-MC-CDSK) chaotic communication system based on Schmidt orthogonalization is proposed. At the transmitter, Schmidt orthogonalization algorithm is used to generate N completely orthogonal chaotic signals which are copied P times as reference signals. N information signals are added up for transmission in each group and multi-carrier is used to transmit MN user information per frame. At the receiver, the signal is demodulated by a matched filter, then the signal is averaged by a moving average filter to suppress the noise and demodulated by correlation. The BER formula of the system in Additive White Gaussian Noise (AWGN) channel and multipath Rayleigh fading channel are derived and simulated. The results show that the BER performance of the system is better than that of many multi-carrier chaotic communication systems and the data transmission rate is improved obviously compared with CDSK system. Theoretical basis for the future application of the system to practical communication systems is provided in the paper and shows strong feasibilities in future engineering application.