Research On Key Technologies Of Chaotic Underwater Acoustic Spread Spectrum Communication

With the proposal of the strategy of " maritime power " and the state’s attention to maritime rights and interests,underwater acoustic communication,as one of the main means of ocean communication,is receiving more and more attention and discussion.Underwater acoustic communication can effectively help naval vessels,submersibles,detectors with voice and image communication,is a very important and increasingly fierce competition in various countries.However,multipath interference and multipath effects have seriously hindered the development of underwater acoustic communication.Spread spectrum technology has been widely used as one of the three main anti multipath interference technologies.Because of its good multi access performance,strong anti-interference,high concealment and low bit error rate,it is suitable for underwater acoustic communication with obvious multipath effect and multi-path interference.However,there are many problems in spread spectrum codes,such as the limited number of codes,poor performance of correlation functions and poor security,which lead to easy deciphering and so on.Chaotic sequences are highly sensitive to initial values and parameters,and have high linear complexity and large number.Their correlation functions are better than spread spectrum codes.In addition,chaotic sequences are not easy to capture and track,and have strong confidentiality.Therefore,compared with traditional spread spectrum codes,chaotic spread spectrum sequences are more suitable for complex underwater acoustic channels.In this paper,chaotic sequence and spread spectrum technology are combined to do in-depth and systematic research in underwater acoustic communication applications.Aiming at some key problems of chaotic underwater acoustic spread spectrum communication system: chaotic sequence generation;conversion sequence quantization;sequence synchronization;synchronization receiver;design and construction of each module of the system have done a great deal of theoretical derivation and research.The chaotic synchronization spread spectrum communication system,the new sequence quantization method,the new double chaotic sequence,the new synchronization acquisition filter design method,the system module and the overall design are proposed,and the performance is analyzed and compared by the simulation tool.It is shown that the new method in both quantitative balance or correlation is dominant;the filter can simplify the structure and reduce the consumption of resources on the basis of guaranteeing the performance of error model;chaotic codes rate is lower than the traditional spreading codes,to further verify the feasibility of chaotic sequences and spread spectrum technology combined with application in underwater acoustic communication.