A Robust Mixed-Signal Cancellation Approach for Even-Order Intermodulation Distortions in LTE-A/5G-Transceivers

State-of-the-art radio frequency receivers for mobile communications inevitably show nonlinearities, mainly caused by constraints in the analog design of the low-noise amplifier and the mixer. In the widely-used direct-conversion architecture, especially even-order intermodulation products cause interference in the baseband, thereby severely deteriorating the receiver signal-to-noise ratio. While several proposed methods aim to cancel second-order distortions caused by transmitter self-interference, the mitigation of higher-order effects is rarely covered. In this work, we present a novel scalable mixed-signal approach for cancellation of intermodulation distortions up to the sixth order. The interference signal is captured by means of an auxiliary receiver, which also allows to suppress interferences caused by external sources. The auxiliary receive signal serves as a basis for a real-time capable digital processing chain, which replicates and cancels the interference. The effectiveness of the proposed method has been verified using measurement data from real-world scenarios.