Radio Frequency Cancellation Approaches for In-Band Full-Duplex Systems

In-Band Full-Duplex (IBFD) systems typically mitigate self-interference through multiple cancellation layers that combine passive, analog and digital techniques. The RF cancellation component of the analog layer is a critical element that is utilized to reduce the strong interference signals before the receiver’s input. It also helps prevent system saturation and maintains receiver linearity by minimizing spurious signal generation. These cancellers can be designed using time-domain, frequency-domain and/or digitally-assisted approaches, and can be dynamically tuned to alleviate the environmental effects experienced by a practical IBFD node. This talk will provide an overview of these different RF canceller options, discuss their design considerations, and present measurement results of the various techniques as they are inserted into a diverse set of IBFD systems.