关键词: 差分混沌移位键控, 多载波, 降噪, 无信号间干扰

Abstract: Aiming at the dominant drawbacks of traditional multicarrier chaotic keying system relating to poor bit error rate and low information transmission rate, a multicarrier noise reduction differential chaos shift keying scheme with no inter-signal interference is proposed in this paper. The designed orthogonal chaotic signal generator is used to obtain two chaotic carrier signals with orthogonal time domain, thus achieving the purpose of no inter-signal interference. Meanwhile, the introduction of multiple predefined subcarriers and orthogonal modulation techniques further increases the transmission rate of the system. The received signal is averaged for noise reduction using a moving average filter at the receiver, which improves the BER performance of the system. Theoretical BER formulas are derived and Monte Carlo simulation experiments are performed under AWGN channels and multipath Rayleigh fading channels. The research results show that the simulation results are basically consistent with the theoretical analysis, and the system has strong anti-noise performance and multipath interference resistance; compared with the traditional MC-DCSK system, the transmission rate can be increased by four times under the same carrier number, and the SNR can be improved by nearly 3 dB under the same BER performance.

Key words: differential chaos shift keying, multicarrier, noise reduction, no intra-signal interference