Self-Interference Cancellation for Multi-Antenna Full Duplex Radio Systems

Full Duplex (FD) systems are of interest for their capability to achieve a potential twofold increase in spectral efficiency compared with half duplex systems. The feasibility of FD operation is closely related to self-interference suppression capabilities at the receiver's side. The employment of multiple antennas on FD transceivers guarantees not only an augmented spatial processing, but also more degrees of freedom for self-interference reduction. This paper introduces a self-interference mitigation algorithm that employs multi-antenna processing for both augmented communication capability and self-interference mitigation. Practical limitations of FD operations in a small form-factor device are also studied. The self-interference mitigation method exploits the peculiarity of the spatial signals, without the need to modify the radio protocol and without training, achieving its goal through the minimization of the received self-interference power to cope with receiver saturation conditions.