Covert underwater acoustic communication using dolphin sounds.

In November 2012, an experiment demonstrating biological mimicry method for covert underwater acoustic communication (UAC) was conducted at Lianhua Lake in Heilongjiang China. Dolphin whistles were used for synchronization while dolphin clicks were used as information carrier. The time interval between dolphin clicks conveys the information bits. Channel estimates were obtained with matching pursuit (MP) algorithm, which is useful for sparse channel estimation. Adaptive RAKE Equalization was employed at the receiver. Bit error rates were less than 10(-4) with 37 bits per second data rate in the lake trial.