Research On Frequency Band Efficient Utilization Of Underwater Acoustic Communication Based On Chaos

As one of the necessary technical means of coastal defense construction and resources exploration and development,underwater acoustic communication technology has been widely used in commerce,environmental protection and other aspects,such as exploring natural resources in the ocean,collecting sensor data for ecosystem monitoring.At the same time,with the development of ocean resources,the concealment and security of underwater acoustic communication become extremely important.Chaotic communication has become a hot topic in the field of underwater acoustic communication because of its advantages in security.However,due to the wide-band characteristic of chaotic signal,the frequency band utilization of chaotic communication in underwater acoustic channel with limited bandwidth is low,which can not meet the need of transmission rate gradually,it hinders its further development in underwater acoustic communication.Aiming at the problems in chaotic underwater acoustic communication,this paper does a lot of theoretical research and puts forward a solution.The work was accomplished as follows:1.The characteristics of underwater acoustic channel and its influence on underwater acoustic communication are summarized,and the BELLHOP channel model is studied,and the acoustic line diagram,impulse response diagram and time delay diagram of the channel are obtained by using the model,so as to deepen the understanding of underwater acoustic channel,the simulation environment is provided for the following algorithm performance verification.2.To solve the problem of low frequency band utilization in chaotic underwater acoustic communication,a scheme of Sparse Code Multiple Access(SCMA)underwater acoustic communication based on chaotic sequence is proposed,in this scheme,a new SCMA codeword is generated from the Eisenstein integer and Logistic chaotic sequences at the transmitter,and then a codebook is generated from the mapping matrix.At the receiving end,the original information is recovered by multi-user detection algorithm and decoding.Low-density spread spectrum technology is adopted to achieve more efficient user resource allocation and improve spectrum utilization.Finally,the feasibility of the proposed communication scheme is verified by simulation experiments in the BELLHOP channel.3.In order to solve the problem of low bandwidth utilization in traditional Frequency Modulated Differential Chaos Shift Keying communication(FM-DCSK),an underwater acoustic communication scheme based on Frequency Modulation Multi User Orthogonal Differential Shift Keying(FM-MU-ODCSK)is proposed.First,a new two Dimensional-Logistic Chebyshev Chaos Map(2D-LCCM)is designed to make it have better Chaos characteristics.Secondly,a FM-MU-ODCSK communication scheme based on2D-LCCM is proposed,which improves the spectrum utilization and is used in the BELLHOP channel model...