Co-time Co-frequency Full Duplex technology applied to VDES: two-stage self-interference signals cancellation technique in the analogue domain

As a potential key technology for 6G communication technology, Co-time Co-frequency Full Duplex technology can be able to improve the spectrum utilization. In this paper, it is applied to the waterborne VHF data exchange system, which is used to alleviate the increasingly scarce spectrum and ensure the safety of ship navigation. Aiming at the problem of self-interference signals in full-duplex communication systems, impedance mismatch terminal and RF cancellation circuits are designed by using the principle of signal superposition and phase cancellation. Physical test respectively, can achieve 50db and 62dB isolation. Subsequently, the two will be used in combination, simulation data show that in the VDES operating frequency band can achieve greater than 70dB isolation. In the analogue domain to achieve a high degree of isolation between the transceiver link, for the subsequent digital domain self-interference phase cancellation to leave sufficient margin for the cancellation.