Bio-inspired Covert Underwater Acoustic Communication Based on Sperm Whale Clicks with Frequency-Hopping Modulation

Covert underwater acoustic communication technology is playing an increasingly important role in the hidden transmission of underwater information. Different from the conventional low probability of intercept and low probability of detection communication methods, a bioinspired covert underwater acoustic communication based on sperm whale clicks with frequency-hopping modulation is proposed. According to the different frequency-band distribution of clicks issued by the same sperm whale at different times or different sperm whales, we modulate the frequency-band distribution of clicks to construct communication codes carrying different encoding information. Then the communication codes are inserted into the original positions of the sperm whale click train to form a communication sequence. Based on the fact that the whale calls are almost always classified into ocean noise and filtered out, the covert communication based on the proposed method is achieved. Simulations are implemented to demonstrate the feasibility and reliability of the proposed covert communication method.