Real-time RF self-interference cancellation for in-band full duplex

Abstract

We demonstrate a real-time RF self-interference cancellation scheme for in-band full duplex using an electrical balance duplexer. The balance network in the duplexer has four 8-bit tunable capacitor banks, creating a four dimensional optimization space with over 4 billion settings. We present a particle swarm optimizer that is able to find a close to optimal solution within 1 ms. The goal of this demo is to show a self-interference cancellation scheme for very dynamic environments. More specifically our demo is able to mitigate instantaneous changes in the antenna impedance in order to keep the self-interference below the threshold.