Spectral Analysis of Predistorted Non-Linear Amplified Multicarrier Signals

The aim of this paper is to analytically evaluate the spectral regrowth at the output of a transmitter due to the nonlinear components such as the power amplifier (PA). Therefore, we propose a generalization of existing closed-form expression for the Power Spectral Density (PSD) of nonlinear amplified multicarrier signals to be valid for any type of modulation. Then, we derive the PSD of the amplified multicarrier signal taking into account the predistortion technique. To the best of our knowledge, no analytical PSD expression of the transmitted signal taking into account the predistortion technique exists in the literature. Such analytical expression could be of particular interest to those involved in the design of cellular communications systems. In fact, this analytical expression is very useful to determine the optimal configuration of the PA and the predistortion technique that allows to obtain the maximum PA efficiency while satisfying the linearity requirements.