Digital-domain assisted RF cancellation of nonlinear wideband self-interference for co-site wireless communication systems

摘要

In this paper, a digital-domain assisted radio-frequency (RF) cancellation architecture is proposed to cancel the nonlinear wideband self-interference (SI) signal for co-site communication systems. First, a cancellation chain is introduced to reconstruct and suppress the SI signal received at the receiver chain. Then, we derive two nonlinear models with the Hammerstein model and Wiener model employed for the transmit chain, respectively. The proposed models can predicate the SI coupling characteristics, which include the transmit chain and wireless channel, more accurately for the nonlinear wideband SI signal. Next, the coefficients of both linear and nonlinear component in the SI chain are integrated into a signal vector, which is linear with respect to the output samples. Therefore, simple least-squares (LS) algorithm is adopted in the estimation of model coefficients by taking the linearity of the proposed models. Finally, experimental results validated that the proposed scheme has a superior interference cancellation performance for nonlinear wideband self-interference.