A Full-Duplex Technology Based on the Doppler Effect

Full-duplex technology can improve bandwidth and energy efficiency but has serious self-interference. In this paper, we introduce a novel full-duplex communication scheme that leverages the Doppler effect. By rotating the circular antenna array, the Doppler frequency shift is introduced into the received uplink (UL) signal, and the UL signal can be separated from the downlink (DL) signal in the frequency domain, thus eliminating self-interference. In order to maximize the interference-free bandwidth, an antenna switching criterion to maximum frequency offset interval is proposed for antenna switching control. Moreover, an antenna switching module based on the above criterion and a Doppler frequency shift compensation module are designed. Simulation results show that the proposed scheme can effectively avoid interference between UL and DL signals and achieves a substantial capacity improvement compared to conventional systems.