Chaos Synchronization And Its Application

With the widely use of the computer and various communication network, secret communication becomes a new researching focus in the science fields of computer communication, network, application mathematics, microelectronics and so on. Chaotic motion is a complex nonlinear motion, whose trajectory of the orbits in the phase plane is very complex but not stochastic, and can be observed in fairly simple dynamical systems. Chaotic signals are ergodicity, aperiodie, uncorrelated, boardband and noise-like and have been proved to be useful for secure communication. In all the areas, chaotic synchronization and its application can be observed an ongoing and growing research interest.The main content of this paper contains the analysis of the synchronization of continues-time chaotic dynamical system and its application on secret communication. The main contributions are as following:1. In this paper, the conception of chaos synchronization and generalized chaos synchronization is presented. Hyperchaos synchronization between the two hyperchaotic systems by using linear feedback control is proposed. Lyapunov stability theory proved that the synchronized method works well. Then, hyperchaos synchronization between two different hyperchaotic systems by using active control is presented. The feedback linearization was used to convert the nonlinear chaotic system into linearized system, and can rapidly to achieve hyperchaotic synchronization. Simulation results show that the proposed method is widely applicable.2. A method for transmitting ternary logic digital signals based on chaos masking, using a new unified chaotic system is researched. Both software and hardware simulation shows that this secure scheme is feasible and available. Based on this, chaos parameter modulation and CSK modulation is used to improve the system's communication rate. The secure digital communication system is high secure and simple in circuit.3. A new method of communication using hyperchaotic signal is presented. In the receiving end of system, the phase recognizing is done to the receiving signal using the theory of in-phase synchronization and anti-phase synchronization. Then, the original input signal will be obtained. Simulation shows that the proposed scheme is highly secure, highly rate, simple in circuit and easy to be integrated.4. Research on the hyperchaotic synchronization based on adaptive feedback controllors, moreover, as an application, the proposed scheme is then applied to secure communication. The two hyperchaotic systems which consist of different structures and parameter mismatch are studied. Through theoretic proving, it was found that the hyperchaotic synchronization can be obtained by the two adaptive linear feedback controllers. The hyperchaos is-used in the two-channel communication scheme: an output of the chaotic transmiter is sent for synchronization only, while the other channel transmits a signal generated from a highly nonlinear function of the chaotic states and the information-bearing signal. Due to the hyperchaos and the separation of the synchronization and the encryption of the information-bearing signal, the security of the communication is improved.