Digital Self-Interference Cancellation in the Presence of Phase Noise for Full-Duplex Communications

Abstract

In wireless full-duplex communication systems, selfinterference (SI) cancellation is a key technique to ensure simultaneous transmission and reception on the same carrier frequency. During the SI cancellation, it has been shown that the oscillator phase noise dramatically affects the cancellation capability and thus needs consideration and suppression. In this paper, a novel time-domain digital SI cancellation approach is proposed to cancel the transmitter and receiver phase noises along with the incoming SI signal, without estimating either the SI channel response or the phase noise associated coefficients. For proofof-concept evaluation, simulations are performed on orthogonal frequency division multiplexing (OFDM)-modulated signals of 20 MHz bandwidth with 16 QAM constellations to verify the effectiveness of the proposed method. It is demonstrated that the proposed approach provides at least 3 dB improvement on the SI cancellation capability and at least 5 dB increase on the interference tolerance over the conventional cancellation approach that uses the frequency domain SI channel estimation.