1 Introduction
1.1 Related Surveys
1.2 Our Contribution
2 An Overview of Federated Learning Systems
2.1 Background
2.2 Definition
2.3 Compare with Conventional Federated Systems
2.4 System Components
3 Taxonomy
3.1 Data Partitioning
3.2 Machine Learning Models
3.3 Privacy Mechanisms
3.4 Communication Architecture
3.5 Scale of Federation
3.6 Motivation of Federation
4 Summary of Existing Studies
4.1 Methodology
4.2 Individual Studies
4.3 Open Source Systems
5 System Design
5.1 Effectiveness
5.2 Privacy
5.3 Efficiency
5.4 Autonomy
5.5 The Design Reference
5.6 Evaluation
6 Case Study
6.1 Mobile Service
6.2 Healthcare
6.3 Finance
7 Vision
7.1 Heterogeneity
7.2 System Development
7.3 FL in Domains
8 Conclusion