From Centralized to Decentralized Federated Learning: Theoretical Insights, Privacy Preservation, and Robustness Challenges
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Abstract (arXiv)
Federated Learning (FL) enables collaborative learning without directly sharing individual's raw data. FL can be implemented in either a centralized (server-based) or decentralized (peer-to-peer) manner. In this survey, we present a novel perspective: the fundamental difference between centralized FL (CFL) and decentralized FL (DFL) is not merely the network topology, but the underlying training protocol: separate aggregation vs. joint optimization. We argue that this distinction in protocol leads to significant differences in model utility, privacy preservation, and robustness to attacks. We systematically review and categorize existing works in both CFL and DFL according to the type of protocol they employ. This taxonomy provides deeper insights into prior research and clarifies how various approaches relate or differ. Through our analysis, we identify key gaps in the literature. In particular, we observe a surprising lack of exploration of DFL approaches based on distributed optimization methods, despite their potential advantages. We highlight this under-explored direction and call for more research on leveraging distributed optimization for federated learning. Overall, this work offers a comprehensive overview from centralized to decentralized FL, sheds new light on the core distinctions between approaches, and outlines open challenges and future directions for the field.
Key facts. Cited by 4 papers in the map (data through 14 Oct 2026). Builds on 91 of its 153 references that are in the map. First posted on arXiv 10 Mar 2025.
Builds on
91 of 153 references.
References · 91
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38 more
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50 most cited of 91 All 91 (JSON)
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Citing papers per year: 2025: 3; 2026: 1.
4 papers.
- 2025Byzantine-Resilient Federated Learning via Distributed Optimizationcited by 3
- 2025Generalization Error Analysis for Attack-Free and Byzantine-Resilient Decentralized Learning with Data Heterogeneitycited by 1
- 2026Decision-Focused Federated Learning Under Heterogeneous Objectives and Constraintscited by 1
- 2025DFed-SST: Building Semantic- and Structure-aware Topologies for Decentralized Federated Graph Learningcited by 0
- 2026Decision-Focused Federated Learning Under Heterogeneous Objectives and Constraints21 Apr 2026
- 2025DFed-SST: Building Semantic- and Structure-aware Topologies for Decentralized Federated Graph Learning15 Aug 2025
- 2025Generalization Error Analysis for Attack-Free and Byzantine-Resilient Decentralized Learning with Data Heterogeneity11 Jun 2025
- 2025Byzantine-Resilient Federated Learning via Distributed Optimization13 Mar 2025