5G System Architecture
Architecture Overview
The 5G System (5GS) represents a fundamental shift from traditional monolithic network architectures to a cloud-native, service-based approach. This new architecture enables unprecedented flexibility, scalability, and the ability to support diverse use cases through network slicing and service customization.
🏗️ 5G System Architecture Layers
📱 User Equipment (UE) Layer
5G-capable devices, smartphones, IoT sensors, industrial equipment
📡 Radio Access Network (RAN)
gNodeB base stations, distributed units, centralized units
☁️ 5G Core Network (5GC)
Cloud-native network functions with service-based interfaces
🌐 Data Networks
Internet, enterprise networks, cloud services, applications
🎯 Key Architecture Principles
- Service-Based Architecture (SBA) with microservices approach
- Cloud-native design with containerization and orchestration
- Separation of control plane and user plane functions
- Network slicing for service customization
- Edge computing integration for ultra-low latency
- Open interfaces and vendor interoperability
Service-Based Architecture (SBA)
The 5G Core adopts a Service-Based Architecture where network functions communicate through well-defined service interfaces. This approach enables modular design, independent scaling, and rapid service deployment using cloud-native principles.
🔐 AMF - Access and Mobility Management
Handles registration, authentication, mobility management, and connection management for user equipment.
🎛️ SMF - Session Management Function
Manages PDU sessions, IP address allocation, traffic steering, and policy enforcement for user sessions.
🚪 UPF - User Plane Function
Handles packet routing, forwarding, traffic inspection, and serves as anchor point for mobility.
🗃️ UDM - Unified Data Management
Stores and manages user subscription data, authentication credentials, and service profiles.
📋 PCF - Policy Control Function
Provides policy rules for service flows, charging policies, and QoS control decisions.
🔍 NRF - Network Repository Function
Service discovery and registration for network functions, enabling dynamic service location.
Radio Access Network (RAN)
The 5G RAN introduces a disaggregated architecture that separates radio functions into different units, enabling flexible deployment models and better resource utilization through centralization and virtualization.
📻 RU - Radio Unit
Handles radio frequency functions, antenna interface, and digital-to-analog conversion at the cell site.
📶 DU - Distributed Unit
Manages real-time L1 and L2 processing, scheduling, and radio resource management functions.
🏢 CU - Central Unit
Handles non-real-time L2 and L3 functions, RRC processing, and connection to 5G core network.
📡 RAN Benefits
- Centralized processing and resource pooling
- Improved spectral efficiency and coverage
- Flexible deployment options (indoor/outdoor)
- Enhanced coordination for interference management
- Cost reduction through resource sharing