Photonic-Enabled RF Canceller for Wideband In-Band Full-Duplex Wireless Systems

In-band full-duplex (IBFD) wireless systems offer the ability to revolutionize frequency spectrum utilization for future networks. This is only possible if the self-interference generated by each wireless node is sufficiently mitigated, and becomes more challenging as the bandwidth increases. RF cancellation is one of the critical components that enables this interference reduction, but has previously been limited to narrowband operation or restricted to distinctive environments. This paper presents a novel RF canceller that utilizes photonic components to create a wideband vector modulator architecture with tunable time-delay taps. A prototype system with 20 canceller taps has been demonstrated to provide 25 and 20 dB of cancellation over 500-MHz and 1-GHz instantaneous bandwidths, respectively, and is tunable between 0.5 and 5.5 GHz. This unique photonic-enabled RF canceller design provides a path forward to achieve the wideband operation and high tap counts that will be required to successfully deploy future wireless systems with IBFD technology.