Iterative Predistortion of the Nonlinear Satellite Channel

Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) is the current European standard for satellite broadcast and broadband communications. It relies on high-order modulations up to 32 amplitude/phase-shift keying (APSK) in order to increase the system spectral efficiency. Unfortunately, as the modulation order increases, the receiver becomes more sensitive to physical-layer impairments and, notably, to the distortions induced by the power amplifier and the channelizing filters aboard the satellite. The predistortion of a nonlinear satellite channel has been studied for many years. However, the performance of existing predistortion algorithms generally becomes poor when high-order modulations are used on a nonlinear channel with long memory. In this paper, we investigate a new iterative method that predistorts the blocks of transmitted symbols to minimize the Euclidian distance between the transmitted and received symbols. We also propose approximations to relax the predistorter complexity while keeping its performance acceptable.