Design And Implementation Of The Chaotic Spread Spectrum Communication System Based On Mixed Programming

Recently, with the rapid development of the technology in spread spectrum communication,Spread spectrum code has become the important factor of the security performance in communication system.Because the traditional spread spectrum codes have low complexity,short length, few variety and other problems. Spread spectrum communication system can not satifsy the growing appetite for performance,Chaotic sequence is one possible source.The chaotic sequences as spreading codes has become the main method to improve the security performance of the spread spectrum communication system.with so many kinds of chaotic sequence,comparative analysis is paticulary important to the performance of different chaotic sequences.Nowadays,there has been a series of index to evaluate the performance of the sequence in theory,and the spread spectrum communication system are mostly developed by Matlab language,although the system based on Matlab language has great advangtages in caculation,but it has the poor compatibility and does not support multithreading,this caused gread obstacles to the chaotic theory’s engineering.In order to combine the advantages of the two languages,the development of the mixed programming has been used in the spread spectrum communication system,Matlab is used to solve complex function of the opration and the C# is used to construct the interface of software and the basic function.The main work of this paper can be described from the following four aspects:1.The eassy delved into the chaotic performance and phase space reconstruction theory. According to defects of the traditional Tent,this paper put forward a kind of improved Tent sequence and a mixed programming design of spread spectrum communication system by Simulation and application requirements.The paper designed and developmented the chaotic evaluation index system based on the simulation requirements in performance of chaotic sequence.The system can simulate the performance index of the chaotic sequence,and it also can be used to compare another sequence as the evaluation standard.The theory of chaotic sequence has been varified by this.2.The paper designed and developmented the multi-user spread spectrum communication system based on the simulation requirements in communication of chaotic sequence.The system used chaotic sequences as the spreading codes to simulate in the model of communication system and to evaluate the applycation work of sequence for different channels,different users and different interferenc conditions.3. The paper designed and developmented the Chaotic secure communication based on the simulation requirements in applycation of chaotic sequence.The chaotic sequence will be applied to the image encryption in this system,through the way of encryption and decryption the security can be verified by chaotic encryption method.4. It also tested the interface and function of the system,Not only proved the good perfermance of chaotic sequence,but also showed the broad applycation prospects and use value.In particulary,The perfermance of new sequence has been evaluated in thesis,the new sequence compared with the original Tent sequence to varify it’s superiority,and it verified the feasibility of cascade method to enhance the Lyapunov index at the same time.The system was developed by mixed programming can complete the complicated computin,reduce the difficulty of development,improve the aspects of compatibility and interface,that has great application value.