A Full Link Wideband Predistortion Based on Under-sampled Feedback Signal for Satellite Communications

The traditional predistortion techniques are commonly used for linearize High Power Amplifiers(HPA) settled in ground-station or on satellite, which can not achieve a full-link linearization. In addition, it is complex for wideband signal transmission in DVB-S2x scenario to implement DPD, especially for Analog to Digital Converter(ADC) sampling the signal feedback from output of HPA. This paper presents a new approach to reduce the nonlinear distortion in the full link with an under-sampled feedback signal. This method avoids adding an extra receiving chain which gets the signal coupled back from the transmitter and mitigates HPA nonlinearity in gateway and on satellite at the same time. Moreover, the QR Decomposition-Recursivfe Least Squares(QR-RLS) algorithm based on the under-sampled signal is derived to identify the HPA model. Simulation results show that the proposed approach gets good performance for the full link DPD and has similar linearization capability compared to the conventional full-rate DPD with much lower feedback cost.