Backscattering Interference Compensation for Full-Duplex Underwater Wireless Optical Communication

Underwater wireless optical communication (UWOC) is attracting growing attention because of its higher communication bandwidth than underwater wireless acoustic communication (UWAC). In addition to increasing transmission distance and bitrate, enabling bidirectional data exchange is also crucial to ensure the reliability and stability of full-duplex (FD) UWOC links, which are significantly affected by backscattering interference (BI). Current FD-UWOC studies are mainly based on time-division duplexing (TDD) and wavelength division multiplexing (WDM), in which duplex signals are transmitted with either time or wavelength separation without BI compensation. In this paper, a backscattering interference compensation (BIC) method for simultaneous single-wavelength FD-UWOC is proposed. Experiment results show, the signal distortion caused by BI can be significantly compensated under certain conditions with BIC, enabling a simultaneous single wavelength FD-UWOC with one-way maximum data rate of 1.2Gbps. Compared to the system without BIC, the BER is reduced from 5×10-1to error-free, 5.12×10-5and 6.0×10-3of 4-QAM, 16-QAM and 64-QAM respectively, with SNR improved by 24.45dB, 25.62dB and 13.80dB.