Feasibility of 256/1024-QAM Transmission under Time-Varying Self-Interference in Full-duplex Mobile Communications

Full-duplex mobile communication is considered as an access method between base station (BS) and user equipment (UE) enabling simultaneous transmission and reception on the same carrier frequency, which can double spectral efficiency compared with conventional frequency division duplex (FDD) and time division duplex (TDD) methods. To achieve this, it is essential to establish a technology that eliminates self-interference (SI). We have been investigating a frequency domain adaptive SI canceller using a demodulation reference signal (DMRS) defined in 5G, as well as a time-domain SI canceller. This paper investigates the transmission performance of QAM-OFDM signals under time-varying SI conditions for frequency domain SI canceller. Specifically, the BERs of QAM-OFDM signals are demonstrated as parameters of the time variation speed of SI. The simulation results verify that the frequency domain adaptive SI canceller can sufficiently eliminate SI and high-order QAM transmission is feasible when the time variation speed of SI is relatively slow.