Multi-Gateway Data Predistortion for Non-Linear Satellite Channels

Joint on-board amplification of multiple carriers reduces hardware and weight, enabling cost-efficient satellite architectures. However, on-board power amplification is inherently a non-linear operation and the distortion effects drastically increase when the high-power amplifier (HPA) is operated in multiple-carrier mode due to the generated inter-modulation products. In order to achieve the desired on-board power efficiency and to reduce the non-linear distortion, specific countermeasures need to be put in place. Emerging multi-gateway satellite systems where, in the most general case, each carrier is uplinked independently from a different gateway, would gain further flexibility by adopting a multicarrier architecture. While advanced predistortion techniques are already available for the single-gateway scenario, no solution has been proposed for the multi-gateway multicarrier scenario. In this work, we propose novel distributed predistortion techniques to improve spectral and power efficiency in multi-gateway non-linear satellite channels. Further, we analyze the multiple-carrier predistortion parameter estimation error with respect to noise sensitivity, proposing a robust version of the indirect learning method. Distributed processing becomes sensitive to synchronization amongst the actors, and we present an evaluation of the sensitivity of proposed techniques to imperfections.