针对水下通信隐蔽性的需求,克服传统固定载波调制方式带来的声源暴露问题,提出一种基于海豚叫声的仿生伪装水声通信方法,使通信信号被当作海洋生物噪声排除,达到隐蔽通信的效果.研究了海豚叫声信号特点,利用海豚哨声信号实现同步与识别,采用差分脉冲位置调制方法,信息调制在相邻海豚嘀嗒声信号的时间间隔,采用压缩传感体制下的匹配追踪技术估计信道,虚拟时反技术实现信道均衡.湖试结果验证了该方法的有效性和可行性,接收声信号与发射信号声音上具有很高的相似度,可以达到伪装隐蔽的效果.实验中水平距离2km,通信速率不小于29bps时,误码率可以达到10-4以下
An underwater acoustic communication scheme using intrinsic dolphin sounds is proposed to overcome the sound exposure derived from traditional fixed carrier modulation for covert communication in this paper. The communication signal can be detected but it could easily be excluded in the process of recognition/classification by an adversary. This is because the signal resembles dolphin sounds. Properties of dolphin sounds are investigated in this paper. Synchronization in this scheme is achieved by using dolphin whistles while dolphin clicks are used as information carrier. The time interval between dolphin clicks conveys information. Channel equalization is performed by passive time reversal mirror technique, whereas channel estimation is done through matching pursuit method under the theory of compressive sensing. The efficiency and feasibility of the proposed method are verified by lake trial. The received signal and emission mimic bio-signal are very similar. Bit error rate less than 10--4 is achieved above 29 bps to a distance of about 2 km.