ILoRA: Federated Learning with Low-Rank Adaptation for Heterogeneous Client Aggregation

Fuente: arXiv
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Main Authors: Zhou, Junchao, Liu, Junkang, Shang, Fanhua
Format: Preprint
Published: 2025
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author Zhou, Junchao
Liu, Junkang
Shang, Fanhua
author_facet Zhou, Junchao
Liu, Junkang
Shang, Fanhua
contents Federated Learning with Low-Rank Adaptation (LoRA) faces three critical challenges under client heterogeneity: (1) Initialization-Induced Instability due to random initialization misaligning client subspaces; (2) Rank Incompatibility and Aggregation Error when averaging LoRA parameters of different ranks, which biases the global model; and (3) exacerbated Client Drift under Non-IID Data, impairing generalization. To address these challenges, we propose ILoRA, a unified framework that integrates three core innovations: a QR-based orthonormal initialization to ensure all clients start in a coherent subspace; a Concatenated QR Aggregation mechanism that fuses heterogeneous-rank updates via concatenation and decomposition, preserving information while maintaining dimension alignment; and an AdamW optimizer with rank-aware control variates to correct local updates and mitigate client drift. Supported by theoretical convergence guarantees, extensive experiments on vision and NLP benchmarks demonstrate that ILoRA consistently achieves superior accuracy and convergence stability compared to existing federated LoRA methods.
format Preprint
id arxiv_https___arxiv_org_abs_2511_16069
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle ILoRA: Federated Learning with Low-Rank Adaptation for Heterogeneous Client Aggregation
Zhou, Junchao
Liu, Junkang
Shang, Fanhua
Machine Learning
Federated Learning with Low-Rank Adaptation (LoRA) faces three critical challenges under client heterogeneity: (1) Initialization-Induced Instability due to random initialization misaligning client subspaces; (2) Rank Incompatibility and Aggregation Error when averaging LoRA parameters of different ranks, which biases the global model; and (3) exacerbated Client Drift under Non-IID Data, impairing generalization. To address these challenges, we propose ILoRA, a unified framework that integrates three core innovations: a QR-based orthonormal initialization to ensure all clients start in a coherent subspace; a Concatenated QR Aggregation mechanism that fuses heterogeneous-rank updates via concatenation and decomposition, preserving information while maintaining dimension alignment; and an AdamW optimizer with rank-aware control variates to correct local updates and mitigate client drift. Supported by theoretical convergence guarantees, extensive experiments on vision and NLP benchmarks demonstrate that ILoRA consistently achieves superior accuracy and convergence stability compared to existing federated LoRA methods.
title ILoRA: Federated Learning with Low-Rank Adaptation for Heterogeneous Client Aggregation
topic Machine Learning
url https://arxiv.org/abs/2511.16069