Pre-nulling for self-interference suppression in full-duplex relays

Abstract

We consider a full-duplex relay that simultaneously receives and transmits signals over a shared channel and propose techniques for suppressing self-interference caused by huge difference in the signal power of the transmitted and received signals. In particular, a pre-nulling method for self-interference reduction is introduced. It is shown that self-interferences can be efficiently suppressed by pre-nulling without degrading bit error rate (BER) performance of the destination receiver in the flat channel environment. In addition, a hybrid method combining the proposed pre-nulling method and conventional adaptive interference suppressor is proposed to reduce the selfinterference further. It is shown by simulations that the hybrid method can secure more relay gain margin for stable operation of full-duplex relays.