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Main Authors: Wang, Ruomeng, Xu, Yin, Tang, Aimin, Ou, Xiaowu, Zhu, Jun, He, Dazhi, Wang, Lifeng, Zhang, Wenjun
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2606.01714
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author Wang, Ruomeng
Xu, Yin
Tang, Aimin
Ou, Xiaowu
Zhu, Jun
He, Dazhi
Wang, Lifeng
Zhang, Wenjun
author_facet Wang, Ruomeng
Xu, Yin
Tang, Aimin
Ou, Xiaowu
Zhu, Jun
He, Dazhi
Wang, Lifeng
Zhang, Wenjun
contents Cell-free massive multiple-input multiple-output (CF-mMIMO) systems provide enhanced coverage and capacity for next-generation wireless networks. However, CF-mMIMO systems face significant challenges in downlink power allocation (PA) due to imperfect channel state information (CSI), severe multi-user interference (MUI), and high computational complexity. To address these issues, rate-splitting multiple access (RSMA) is adopted as a robust interference management strategy. Accordingly, this paper proposes an unsupervised and scalable graph neural network (GNN) framework for PA in rate-splitting CF-mMIMO (RS-CF-mMIMO) systems, relying exclusively on large-scale fading (LSF) coefficients without instantaneous CSI. To resolve the dimensionality mismatch in dynamic networks, we introduce a slice-based adaptive layer that projects variable-dimension features into a fixed latent space. This mechanism enables a unified model to generalize across diverse topologies without retraining. Within this architecture, the sum spectral efficiency (SE) is maximized under per-AP power constraints, assuming maximum-ratio precoding for common streams and regularized zero-forcing precoding for private streams. We also derive a weighted minimum mean-square error-alternating direction method of multipliers (WMMSE-ADMM) algorithm as a performance upper bound. Extensive simulations verify that the proposed GNN framework achieves near-optimal SE and outperforms unsupervised deep neural networks (DNNs) across diverse system sizes and pilot assignment schemes. Furthermore, the scalable variant maintains robust performance while reducing the trainable parameter count by over 57% relative to DNNs and decreasing inference latency by up to three orders of magnitude compared with WMMSE-ADMM.
format Preprint
id arxiv_https___arxiv_org_abs_2606_01714
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scalable GNN-Based Power Allocation for Rate-Splitting Cell-Free Massive MIMO Systems
Wang, Ruomeng
Xu, Yin
Tang, Aimin
Ou, Xiaowu
Zhu, Jun
He, Dazhi
Wang, Lifeng
Zhang, Wenjun
Signal Processing
Cell-free massive multiple-input multiple-output (CF-mMIMO) systems provide enhanced coverage and capacity for next-generation wireless networks. However, CF-mMIMO systems face significant challenges in downlink power allocation (PA) due to imperfect channel state information (CSI), severe multi-user interference (MUI), and high computational complexity. To address these issues, rate-splitting multiple access (RSMA) is adopted as a robust interference management strategy. Accordingly, this paper proposes an unsupervised and scalable graph neural network (GNN) framework for PA in rate-splitting CF-mMIMO (RS-CF-mMIMO) systems, relying exclusively on large-scale fading (LSF) coefficients without instantaneous CSI. To resolve the dimensionality mismatch in dynamic networks, we introduce a slice-based adaptive layer that projects variable-dimension features into a fixed latent space. This mechanism enables a unified model to generalize across diverse topologies without retraining. Within this architecture, the sum spectral efficiency (SE) is maximized under per-AP power constraints, assuming maximum-ratio precoding for common streams and regularized zero-forcing precoding for private streams. We also derive a weighted minimum mean-square error-alternating direction method of multipliers (WMMSE-ADMM) algorithm as a performance upper bound. Extensive simulations verify that the proposed GNN framework achieves near-optimal SE and outperforms unsupervised deep neural networks (DNNs) across diverse system sizes and pilot assignment schemes. Furthermore, the scalable variant maintains robust performance while reducing the trainable parameter count by over 57% relative to DNNs and decreasing inference latency by up to three orders of magnitude compared with WMMSE-ADMM.
title Scalable GNN-Based Power Allocation for Rate-Splitting Cell-Free Massive MIMO Systems
topic Signal Processing
url https://arxiv.org/abs/2606.01714