Three-stage self-interference cancellation for small form factor realization of in-band full duplex

In-band full-duplex (IBFD) radio transceivers, which transmit and receive on the same frequency at the same time may potentially double the spectral efficiency of future radio networks. However, to achieve this requires high isolation between the transmitter and receiver in order to suppress the self-interference (SI) which results from the co-located co-channel transmitter and receiver. This paper presents an IBFD transceiver architecture which consists of two stages of RF cancellation and one stage of digital baseband cancellation. A prototype based on this architecture has been implemented and performance measured. The system operates over a 20 MHz bandwidth at 720 MHz, and achieves 100 dB of transmit-to-receive isolation, suppressing the SI to within 3 dB of the noise floor of the receiver.