Performance analysis on the self-mixed interference cancellation in direct conversion receivers

In this paper, we propose a novel receiver structure for cancelling self-mixed interferences in direct conversion receivers. The proposed receiver structure is based on the adaptive interference cancellation (IC) using an adaptive algorithm such as a least-mean-square (LMS). The reference signal for the adaptive IC is obtained from the received signal itself. Thus, the proposed method can mitigate the self-mixed interference without any additional information on the self-mixed interference. Moreover, the signal-to-interference ratio (SIR) performance of the proposed cancellation method is theoretically analyzed. The simulation results indicate that the numerical SIR performance is well matched with the theoretical SIR performance. Also, the proposed cancellation method cancel the self-mixed interference almost perfectly even when the power of the received interference signal is 50dB larger than that of the received desired signal.