Reference signal aided self-interference cancellation for in band full duplex underwater wireless optical communication

A novel self-interference cancellation method for in-band full-duplex (IBFD) underwater wireless optical communication (UWOC) system is proposed and experimentally verified. This method reduces the self-interference to its intrinsic noise level using a reference optical signal whose amplitude is opposite to the self-interference signal, together with a deep neural network to compensate for the nonlinear distortion enhanced by increased DC. The bit error rates (BERs) before and after self-interference cancellation at different data rates are tested and compared with the existed polarization-based cancellation scheme. Results presented in this paper show that more than 10dB self-interference cancellation ratio can be achieved by the proposed scheme at 100 MHz signal rate, and outperforms the polarization-based scheme. With the assistance of the proposed method, a data rate of 100Mbps was achieved simultaneously at the uplink and downlink within IBFD based UWOC.