Comparison of signal predistortion schemes based on the contraction mapping for satellite communications with channel identification

摘要

The expected increase of data rates in future satellite communications (DVB-S2X) will require higher-order modulations and sharper roll-off, which makes the transmission more sensitive to non-linear interference due to on-board amplifiers. One solution is the predistortion of the signal that is carried out at the transmitter either on the data sequence (data-based) or on the modulated signal (signal-based). In this paper, we focus on single carrier communication and consider two signal-based predistortion techniques relying on the contraction mapping theorem, optimized from an error defined either from the data (data-optimized) or from the modulated signal (signal-optimized). We compare both schemes according to different figures of merit (normalized minimum square error, adjacent channel interference, total degradation and robustness towards channel identification). We show that, under realistic satellite transmission conditions, including satellite channel model and channel identification, the data-optimized signal predistortion scheme outperforms the signal-optimized scheme in terms of total degradation, whereas the signal-optimized scheme minimizes the adjacent channel interference due to spectral regrowth.