Central Server Free Federated Learning over Single-sided Trust Social Networks

TL;DR

This paper introduces a novel federated learning algorithm called Online Push-Sum (OPS) designed for social networks without a central server and with unidirectional trust, providing theoretical guarantees and demonstrating benefits of communication among trusted users.

Contribution

The paper proposes the first central server free federated learning algorithm for unidirectional trust social networks, with rigorous regret analysis and theoretical insights.

Findings

OPS algorithm effectively operates without a central server.

Users benefit from communication with trusted peers.

Theoretical analysis shows convergence and performance guarantees.

Abstract

Federated learning has become increasingly important for modern machine learning, especially for data privacy-sensitive scenarios. Existing federated learning mostly adopts the central server-based architecture or centralized architecture. However, in many social network scenarios, centralized federated learning is not applicable (e.g., a central agent or server connecting all users may not exist, or the communication cost to the central server is not affordable). In this paper, we consider a generic setting: 1) the central server may not exist, and 2) the social network is unidirectional or of single-sided trust (i.e., user A trusts user B but user B may not trust user A). We propose a central server free federated learning algorithm, named Online Push-Sum (OPS) method, to handle this challenging but generic scenario. A rigorous regret analysis is also provided, which shows very interesting results on how users can benefit from communication with trusted users in the federated learning scenario. This work builds upon the fundamental algorithm framework and theoretical guarantees for federated learning in the generic social network scenario.