Kopyto, David JonasDavid JonasKopytoBauch, GerhardGerhardBauch2025-10-242025-10-24202514th International ITG Conference on Systems, Communications and Coding, SCC 2025https://hdl.handle.net/11420/57714In communication over transparent satellite payloads, traveling wave-tube amplifier (TWTA) cause nonlinear distortion to the transmit signal. Together with filters involved in the transmission chain, the TWTA causes distorted decision regions (warping) and intersymbol interference (ISI) at the matched filter output. This nonlinear channel can be compensated by means of data predistortion. The remaining interference results can be interpreted as a channel and the transmit constellation can be optimized for the joint channel with influences from additive white Gaussian noise (AWGN) and phase noise. This work shows how constellation shaping and data predistortion can be designed using neural networks. Particularly, a novel data predistortion algorithm based on a recurrent neural network (RNN) which accounts for the ISI is presented. For constellation shaping, different constrained optimization techniques are presented, including quadrant-symmetric optimization, spiral constellations and amplitude and phase-shift keying (APSK) constellations. All constellations are shaped by implementing the communication chain as an autoencoder, which is trained on a channel with the abovementioned impairments, which occur in satellite links. Resulting constellations are presented together with data predistortion, bit error rate (BER) and information rates.enhttp://rightsstatements.org/vocab/InC/1.0/digital predistortionsatellite communicationsconstellation shapingautoencodersTechnology::621: Applied Physics::621.3: Electrical Engineering, Electronic EngineeringConference Poster not in Proceedingshttps://doi.org/10.15480/882.1594010.15480/882.15940Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting / republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to server or lists, or reuse of any copyrighted component of this work in other worksConference Poster