Self-interference cancellation in full-duplex underwater acoustic communication via dual-hydrophone

Aiming at the problem of strong-power self-interference (SI) in in-band full-duplex (FD) underwater acoustic communication (UWAC) systems, in this paper, we propose an advanced self-interference cancellation (SIC) method that makes use of the differing channel characteristics of two hydrophones. The method effectively cancels the SI signal at the more distant receiver by using the hydrophone closer to the near-end source as a reference. Our approach can dynamically update the channel parameters of the SIC model to maintain stable communication performance. To validate this design, results from both pool and sea-trial experiments are presented. The pool experiments demonstrate approximately 54.75 dB of SIC performance. The bit error rate of the far-end signal remains below 1 ×10-3. In the sea trials, shallow-sea communication was achieved across 50 km with a signal-to-interference ratio of -40 dB. Compared with conventional SIC methods, the proposed method offers stronger SIC capability, particularly when handling nonlinear interference. Furthermore, it can adapt to unknown sources of interference. The results indicate that our method provides a promising solution for SI cancellation in FD-UWAC systems, providing significant theoretical and practical value.