Performance Analysis of Nonlinear Self-Interference Cancellation With Timing Error in Full-Duplex Systems

In this letter, with consideration of the approximation error due to the order of the nonlinear canceller is smaller than that of the nonlinearity model, the performance of the nonlinear self-interference (SI) cancellation is analyzed under imperfect time synchronization. First, the system model of the nonlinear SI cancellation is characterized in the presence of the timing error (TE) between the received SI and the reconstructed one. Next, the closed-form expressions of the residual SI power and the SI cancellation ratio (SICR) are derived for two cases that the order of the nonlinear canceller is smaller than or equal to that of the nonlinear model, which can be used to evaluate the performance degradation of the nonlinear SI cancellation caused by TE. Finally, simulation results reveal that the performance of the nonlinear SI cancellation is sensitive to TE when the nonlinear order of the canceller is sufficient, where the existence of the signal-of-interest (SoI) is also considered.