Neural Precoding in Complex Projective Spaces

Fuente: arXiv
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Main Authors: Abdullah, Zaid, Debbah, Merouane, Chatzinotas, Symeon, Ottersten, Bjorn
Format: Preprint
Published: 2026
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author Abdullah, Zaid
Debbah, Merouane
Chatzinotas, Symeon
Ottersten, Bjorn
author_facet Abdullah, Zaid
Debbah, Merouane
Chatzinotas, Symeon
Ottersten, Bjorn
contents Deep-learning (DL)-based precoding in multi-user multiple-input single-output (MU-MISO) systems involves training DL models to map features derived from channel coefficients to labels derived from precoding weights. Traditionally, complex-valued channel and precoder coefficients are parameterized using either their real and imaginary components or their amplitude and phase. However, precoding performance depends on magnitudes of inner products between channel and precoding vectors, which are invariant to global phase rotations. Conventional representations fail to exploit this symmetry, leading to inefficient learning and degraded generalization. To address this, we propose a DL framework based on complex projective space (CPS) parameterizations of both the wireless channel and the weighted minimum mean squared error (WMMSE) precoder vectors. By removing the global phase redundancies inherent in conventional representations, the proposed framework enables the DL model to learn geometry-aligned and physically distinct channel-precoder mappings. Two CPS parameterizations based on real-valued embeddings and complex hyperspherical coordinates are investigated and benchmarked against two baseline methods. Simulation results demonstrate substantial improvements in sum-rate performance and generalization, with negligible increase in model complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2603_07811
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Neural Precoding in Complex Projective Spaces
Abdullah, Zaid
Debbah, Merouane
Chatzinotas, Symeon
Ottersten, Bjorn
Machine Learning
Deep-learning (DL)-based precoding in multi-user multiple-input single-output (MU-MISO) systems involves training DL models to map features derived from channel coefficients to labels derived from precoding weights. Traditionally, complex-valued channel and precoder coefficients are parameterized using either their real and imaginary components or their amplitude and phase. However, precoding performance depends on magnitudes of inner products between channel and precoding vectors, which are invariant to global phase rotations. Conventional representations fail to exploit this symmetry, leading to inefficient learning and degraded generalization. To address this, we propose a DL framework based on complex projective space (CPS) parameterizations of both the wireless channel and the weighted minimum mean squared error (WMMSE) precoder vectors. By removing the global phase redundancies inherent in conventional representations, the proposed framework enables the DL model to learn geometry-aligned and physically distinct channel-precoder mappings. Two CPS parameterizations based on real-valued embeddings and complex hyperspherical coordinates are investigated and benchmarked against two baseline methods. Simulation results demonstrate substantial improvements in sum-rate performance and generalization, with negligible increase in model complexity.
title Neural Precoding in Complex Projective Spaces
topic Machine Learning
url https://arxiv.org/abs/2603.07811