Multicarrier Digital Pre-distortion/ EqualizationTechniques for Non-linear Satellite Channels

Two key advances are envisaged for future missions: (a) spectrally efficienttransmission to meet the increasing demand and (b) sharing of satellite capacityamong different links to meet power/mass requirements. Joint amplification ofmultiple-carrier DVB-S2 signals using a single High-Power Amplifier (HPA) is aparticular application of satellite resource sharing. However, effects specific to sucha scenario that degrade power and spectral efficiencies include (a) an increasedAdjacent Channel Interference caused by non-linear characteristic of the HPA and(b) increased peak to average power ratio. The paper studies signal processingtechniques – digital pre-distortion (DPD) at the gateway and equalization (EQ) atthe User Terminal – to mitigate the non-linear effects and improve power as well asspectral efficiencies. While the algorithms for DPD and EQ are described inliterature, their use in multi-carrier scenario is novel and poses new challenges thatare investigated in the paper.