A RF adaptive least mean square algorithm for self-interference cancellation in co-frequency co-time full duplex systems

Considering the radio frequency (RF) self-interference cancellation of the full duplex transceiver, which can transmit and receive simultaneously at the same frequency band. The current studies mainly focus on the feasibility verification, most of which are realized by manual adjustment of the self-interference parameters, and lack of the theoretical analysis of the interference cancellation capability. To solve this problem, an adaptive least mean square (ALMS) algorithm for the self-interference cancellation at the RF stage is presented in this paper. Besides, the convergence and steady state performances of the ALMS algorithm are proved and analyzed, respectively. Analysis and simulation results show that the ALMS algorithm can achieve significant cancellation of the self-interference at the RF stage. Moreover, it is revealed that the interference cancellation performance and convergence speed of the ALMS algorithm are related with the following parameters: the duration per iteration, normalized step size, as well as the ratio of the interference power and total power of the desired signal plus noise.