Research On Secure Communication Based On Chaotic Signal

Chaotic communication becomes an important research because of thecharacteristic of broad spectrum and High-security with the development of theinformation industry. The chaotic communication in ultra-wideband communicationsimproved greatly the security of communications for the military. So, the research ofchaotic communication with practical application is necessary. In addition, Gaussianwhite noise has a flat and wide frequency spectrum, which has higher security andlower interception rate.The main content of this paper is as follows:(1) An improved Differential chaos shift keying system is proposed by adding aguard time interval. The simulations of DSP in different channel show that the improvedsystem has better performance in anti-multipath and lower bit error rate.(2) In way of the traditional Differential chaos shift keying (DCSK) for Ultra-Wideband (UWB)signal transmission system in the process, the transmission efficiency islow and the issue of confidentiality is not high, considered that the Gaussian white noiseas the carrier and into the trade deficit with the broadband system, so as to enhance theconfidentiality of communications systems, the reference noise signal and its delayperiod and after a bit of a binary signal and the modulated signal to form thecommunication channel to send signal. Simulation results show that, compared to thetraditional way of contrast Differential Chaos Shift Keying Ultra-Wideband systems,improved system efficiency and confidentiality in the transmission and otherperformance improvement with the higher, the resulting spectrum is more flat and wide,and avoid the keyed to the system of continuous negative impact.(3) For the chaotic pulse position modulation has higher requirement for thesynchronization of chaotic system, the chaotic pulse position modulation system basedon particle filter is proposed. The system puts the particle filter into the demodulation ofchaotic pulse position modulation. The particle filter is used to solve the problems of thesynchronization by track the signals in the channel. The optimal delay of the system isgiven according to the biggest judgment distance which can not cause the divergence ofthe chaotic map. this will help the receiver demodulate the information sequence correctly.