Semi-Synchronous Personalized Federated Learning over Mobile Edge Networks

TL;DR

This paper introduces a semi-synchronous personalized federated learning algorithm, PerFedS$^2$, that reduces training time and guarantees convergence by optimizing bandwidth and scheduling over mobile edge networks.

Contribution

It proposes a novel semi-synchronous PFL algorithm with convergence guarantees, addressing straggler issues in mobile edge networks.

Findings

PerFedS$^2$ reduces training time compared to synchronous and asynchronous methods.

The algorithm guarantees convergence of training loss.

Experimental results validate the effectiveness of the proposed approach.

Abstract

Personalized Federated Learning (PFL) is a new Federated Learning (FL) approach to address the heterogeneity issue of the datasets generated by distributed user equipments (UEs). However, most existing PFL implementations rely on synchronous training to ensure good convergence performances, which may lead to a serious straggler problem, where the training time is heavily prolonged by the slowest UE. To address this issue, we propose a semi-synchronous PFL algorithm, termed as Semi-Synchronous Personalized FederatedAveraging (PerFedS$^2$), over mobile edge networks. By jointly optimizing the wireless bandwidth allocation and UE scheduling policy, it not only mitigates the straggler problem but also provides convergent training loss guarantees. We derive an upper bound of the convergence rate of PerFedS2 in terms of the number of participants per global round and the number of rounds. On this basis, the bandwidth allocation problem can be solved using analytical solutions and the UE scheduling policy can be obtained by a greedy algorithm. Experimental results verify the effectiveness of PerFedS2 in saving training time as well as guaranteeing the convergence of training loss, in contrast to synchronous and asynchronous PFL algorithms.