Adjacent channel power ratio analysis for an OFDM signal

The nonlinear power amplification of multi-carriers signals generates a lot of perturbations. Among them the power increase in the adjacent channels is studied in this paper. This phenomenon is characterized by the adjacent channel power ratio (ACPR) parameter. The analysis we perform in this paper allows us to find a general expression of ACPR versus the number of signal´s sub-carriers, N. Then, we propose a new ACPR definition which permits to better characterize the increase of the shoulders (spectral regrowth). Another interest of our derivation is that we can find the parameters a₁ and a₃ of the amplifier´s polynomial model for a desired ACPR