Analytical prediction of spectral regrowth and correlated and uncorrelated distortion in multicarrier wireless transmitters exhibiting memory effects

Measurement of non-linearity effects in wireless transmitters had been always difficult under complex digitally modulated signals. On the other hand, blind time domain simulation of these effects is generally time consuming and insufficient. In this study, the authors present new frequency domain closed-form formulas for predicting the spectral regrowth in wireless communication systems/subsystems with fifth-order non-linearity exhibiting memory effects. Particularly, the suggested formulas estimate the power spectral density, as well as the undesirable adjacent-channel and co-channel emissions of the modelled device, under phase-aligned and randomly phase-modulated multitone excitations. In addition, they are able to predict the correlated and uncorrelated distortion powers separately. The efficiency and robustness of the proposed approach has been demonstrated by predicting the output of a laterally diffused metal oxide semiconductor Doherty-based power amplifier. The obtained results have been compared to measurements and those of time-domain simulators and have revealed good accuracy and time efficiency.