Signal predistortion scheme based on the contraction mapping theorem

The need for higher satellite throughtput leads to use multiple-ring constellations, such as the 32-APSK, in order to increase the spectral efficiency. However, these constellations are more sensitive to the non-linear intersymbol interference, generated by the HPA and on-board filters, which can be dealt with by a predistortion scheme at the transmitter. After modelling the satellite channel, we derive a fixed-point formulation of the predistortion problem. Then, we propose a signal predistortion scheme based on the contraction mapping theorem that compensates for the non-linear interference.