Abstract-This article addresses the modeling and cancellation of self-interference (SI) in full-duplex (FD) direct-conversion radio transceivers, operating under practical imperfect radio frequency (RF) components. Firstly, detailed SI signal modeling is carried out, taking into account the most important RF imperfections, namely transmit power amplifier (PA) nonlinear distortion as well as transmitter and receiver IQ mixer amplitude and phase imbalances. The analysis shows that after realistic antenna isolation and RF cancellation, the dominant SI waveform at receiver digital baseband can be modeled through a widely-linear (WL) transformation of the original transmit data, opposed to classical purely linear models. Such WL SI waveform is physically stemming from the transmitter and receiver IQ imaging, and cannot be efficiently suppressed by classical linear digital cancellation. Motivated by this, novel widely-linear digital SI cancellation processing is then proposed and formulated, combined with efficient parameter estimation methods. Extensive simulation results demonstrate that the proposed WL SI cancellation processing clearly outperforms the existing linear solutions, hence enabling the use of practical low-cost RF frontends utilizing IQ mixing in full-duplex transceivers.
For example, REF proposes a novel widely linear digital cancellation processing to mutually mitigate SI and practical hardware imperfections in direct-conversion FD transceiver.
Widely-Linear Digital Self-Interference Cancellation in Direct-Conversion Full-Duplex Transceiver
IEEE Journal on Selected Areas in Communications
IEEE Journal on Selected Areas in Communications
Computer Science Mathematics