Adaptive compensation of nonlinear distortion in multicarrier direct-conversion receivers

In this article, some novel methods for compensating the effects of receiver front-end nonlinearities are introduced. More specifically, we focus on multicarrier or multichannel direct-conversion type receivers where several frequency channels are I/Q downconverted as a whole, with the dynamic range of the wideband signal being considerably high. In this kind of receivers, the harmonic and intermodulation distortion due to strong blocking signals is an obvious limiting factor to the whole receiver performance. The basic idea in this paper is to remove or reduce this type of distortion effects from a specific channel of interest using adaptive interference cancellation combined with proper reference signal generation. The effectiveness of the proposed solutions is illustrated through computer simulations, and some example results are also presented based on measured receiver front-end signals.