High Reliability And High Covert Underwater Acoustic Communication Underwater Acoustic Communication Technology Based On The Chaotic Sequence

As an effective means of wireless transmission of underwater information,underwater acoustic communication technology has broad application prospects in civil and military.But the underwater acoustic channel is one of the most complex wireless channels,and its space-time characteristics seriously affect the robustness of underwater acoustic communication.In the security communication situation,the communication system must not only be robust but also concealed.However,most of the existing covert underwater acoustic communication technology is a simple reference for radio communication,without fully considering the particularity of underwater acoustic channel environment,transmission medium,and transceiver sensor unit,it is difficult to achieve truly effective and robust covert underwater acoustic communication.Orthogonal wideband signal modulation and demodulation method based on the chaotic sequence is purposed to improve the concealment and robustness of the existing underwater acoustic communication in this paper by studying the propagation characteristics of the marine underwater acoustic channel.Because the wide-band signal with orthogonal and sharp autocorrelation is used as the information carrier,and the chaotic sequence with statistical characteristics close to environmental noise is selected as the required wide-band signal to improve the communication concealment in this technology,and the received signal is demodulated by Euclidean distance classifier.The method can effectively suppress the frequency selective fading and environmental noise caused by multi-path propagation of the underwater acoustic channel and can achieve reliable and covert underwater acoustic communication under low SNR conditions.Firstly,this paper introduces the physical characteristics of the underwater acoustic channel and some representative underwater acoustic communication technologies.then an orthogonal wideband modulation method based on chaotic sequence is proposed,and the modulation and demodulation principle of this method is described in detail,the research focuses on the anti-multipath,anti-noise and covert secure transmission ability of orthogonal wideband signal modulation and demodulation methods based on chaotic sequences.A classification decisiondemodulation method is also proposed.Compared with traditional correlation demodulation,which uses multi-way matched filtering,this method only needs one-way matched filtering,which reduces the calculation amount of demodulation algorithms.Finally,compared with the traditional narrowband communication and the direct sequence spread spectrum communication method,it demonstrates the high concealment,high robustness and the simplicity of the algorithm.