Sparse Decentralized Federated Learning
Shan Sha, Shenglong Zhou, Lingchen Kong, Geoffrey Ye Li
TL;DR
This work tackles the efficiency, stability, and privacy challenges of decentralized federated learning (DFL) by introducing Sparse DFL (SDFL) and the CEPS algorithm. CEPS combines a sparsity constraint with 1-bit compressive sensing (1BCS) to drastically reduce communication, while employing inexact ADMM to enable efficient, distributed optimization with partial neighbor participation. Privacy is guaranteed via the Gaussian mechanism, providing $(\\varepsilon,\\delta)$-DP per iteration and cumulatively through adaptive composition, along with theoretical convergence guarantees under standard assumptions. Numerical experiments on linear and logistic regression tasks demonstrate improved communication and computational efficiency without sacrificing accuracy or trustworthiness, outperforming several baseline DFL methods under imperfect communication conditions. This approach offers a scalable, privacy-preserving pathway for robust DFL in complex, bandwidth-constrained networks.
Abstract
Decentralized Federated Learning (DFL) enables collaborative model training without a central server but faces challenges in efficiency, stability, and trustworthiness due to communication and computational limitations among distributed nodes. To address these critical issues, we introduce a sparsity constraint on the shared model, leading to Sparse DFL (SDFL), and propose a novel algorithm, CEPS. The sparsity constraint facilitates the use of one-bit compressive sensing to transmit one-bit information between partially selected neighbour nodes at specific steps, thereby significantly improving communication efficiency. Moreover, we integrate differential privacy into the algorithm to ensure privacy preservation and bolster the trustworthiness of the learning process. Furthermore, CEPS is underpinned by theoretical guarantees regarding both convergence and privacy. Numerical experiments validate the effectiveness of the proposed algorithm in improving communication and computation efficiency while maintaining a high level of trustworthiness.
