Nowadays, a new generation of mobile communication technologies such as satellite phone and videophone have been widely used, but few people know about communication methods underwater. How do people achieve information transmission underwater? New research may give us the answer.

Associate Professor Jiang Jiajia from the State Key Lab of Precision Measuring Technology and Instruments of Tianjin University proposed a new underwater covert acoustic communication method based on a bionic camouflage strategy imitating sperm whales’ calls.

Bionic camouflage covert communication strategy

At present, underwater acoustic signal recognition and classification reconnaissance systems almost always classify the calls of whales/dolphins into ocean noises and filter them out. Based on this fact, Jiajia proposed a new covert communication method. Firstly, a fast and accurate method for extracting the call pulses of a sperm whale is proposed. Then, based on constraint conditions such as the auto-correlation, cross-correlation and correlation thresholds of the extracted call pulses, a large number of communication codes which satisfy the requirements of differential pattern coding are picked out from the call pulse library. Next, according to the laws and features of the sperm whale call sequence, an improved differential pattern coding method with frequency hopping technology will be developed. The communication sequence has a strong camouflage and covert ability and could carry communication information with high covert capability，which have been demonstrated through lake experiments and the neural network signal classifier, respectively.

The method can be extended to other marine mammals and can be widely used in underwater covert communication. In addition, it can find potential applications in a broad range of fields in defense and military.

The research paper titled "Bio-Inspired Steganography for Secure Underwater Acoustic Communications" was published in the IEEE Communications Magazine. The current JCR impact factor (published by the Chinese Academy of Sciences JCR Journal Partition Database) of this journal is 10.435 and ranks 2nd in the communications field. The first author in this paper is Associate Professor Jiang Jiajia of Tianjin University, who has been supported by the 2017 Young Elite Scientists Sponsorship Program launched by the China Association for Science and Technology. The other author of this paper is Professor Duan Fajie from Tianjin University.

By Gao Han

Editors: Jiang Jiajia, Eva Yin & Doris Harringtion