Full-Duplex Adaptive Array

An adaptive antenna array approach to in-band full-duplex (IBFD) communications using multi-channel transceivers is presented. The technique uses multiport transceivers and multi-element arrays at both ends of the link to provide self-interference rejection to allow the doubling of spectral efficiency via simultaneous transmission and reception (STAR). It uses adaptively updated weights for the respective transmit and receive elements and provides for real time adjustment to address time varying multipath and nearby reflections. The approach can also provide frequency response compensation across the band of interest and is fully compatible with beamforming / beam steering and MIMO applications. Experiments confirm greater than 70 dB self-interference cancellation can be achieved. Additional techniques can be used to increase this cancellation further, including digitally assisted analog RF cancellation techniques (50–60 dB cancellation) and fully digital blind source separation (BSS) techniques (20–30 dB cancellation), accumulating a combined cancellation of over 120 dB.