Wideband Self-Interference Cancellation for 5G Full-Duplex Radio Using a Near-Field Sensor Array

Self-interference cancellation (SIC) is an important consideration for 5G wireless transceiver architectures. If successfully implemented, SIC can double spectral efficiency by allowing for in-band full-duplex operation. The main challenge lies in effective cancellation of the interference that is caused by the transmit signal. This paper presents a wide-band digitally controlled, analogue SIC circuit block employing a spatially adjustable near-field vector sensor. A stochastic perturbation algorithm operating in spatial and frequency domains provides efficient optimisation when used in combination with the hardware configuration. The proposed technique provides 35 dB of radio frequency suppression across a channel bandwidth of 100 MHz centred at 2.1 GHz.