Multichannel Adaptive Interference Cancellation for Full-Duplex High Power AM Radios

In space-limited co-located communication systems, wideband transmitters and receivers are deployed for various applications. The strong coupling between transmitters and receivers becomes a major concern. It is crucial to suppress the high power self-interference (SI) to prevent the receiver from working in the nonlinear area, or even saturating. As an effective approach to achieve this, the adaptive interference cancellation (AIC) technology is proposed in the context of a complex high power amplitude modulation radios. In this article, the system-level performance including the interference cancellation ratio requirements and the impact of the AIC on the receiving system is comprehensively studied for the first time. The operating mechanism of a single channel AIC system (AICS) and the configuration of a multichannel AICS are discussed. The performance analysis of the receiving system when implementing the AICS is performed, in terms of the noise figure and the sensitivity. By employing the proposed AICS, very limited effect is observed on the receivers, while the SI is successfully reduced with a high ICR, which fully satisfies the requirements for AM systems. The realization of the multichannel AICS as well as the measured cancellation performance are presented, verifying the proposed concept.