Personalized Federated Fine-Tuning for LLMs via Data-Driven Heterogeneous Model Architectures

ACL ARR 2025 February Submission5028 Authors

Abstract: Large-scale instruction data is essential for aligning pretrained Large Language Models (LLMs) with human instructions, but may contain sensitive information that hinders its public sharing. Federated Learning (FL) enables collaborative fine-tuning of LLMs without data sharing. However, existing approaches to federated LLM fine-tuning usually adopt a uniform model architecture, making it hard to fit the highly heterogeneous data with varying amounts and formats. To address this, we propose FedAMoLE, a lightweight personalized FL framework that enables data-driven heterogeneous model architectures. This framework features an adaptive mixture of LoRA experts (MoLE) module for aggregating heterogeneous models and a reverse selection-based expert assignment strategy that optimizes model architectures based on data distributions. Experiments across five scenarios show that FedAMoLE improves accuracy by an average of 5.14% compared to existing approaches while obtaining good scalability.

Paper Type: Long

Research Area: Machine Learning for NLP

Research Area Keywords: Personalized Federated Learning,Large Language Models,Heterogeneous Model Architectures,Mixture of LoRA Experts,Parameter-Efficient Training

Contribution Types: Approaches to low-resource settings, Publicly available software and/or pre-trained models

Languages Studied: Natural Language

Submission Number: 5028