Fifth Generation Mobile Network

Description

5G is a comprehensive system architecture defined by 3GPP, fundamentally redesigned from previous generations to support a wider range of services and requirements. The system is defined by a clear separation between the Radio Access Network (RAN) and the Core Network (CN). The 5G Access Network (5G-AN), which includes the Next Generation Radio Access Network (NG-RAN) built on gNBs and ng-eNBs, is responsible for all radio-related functions. It connects to the 5G Core Network (5GC) via standardized interfaces (N2 for control plane, N3 for user plane), enabling a service-based architecture (SBA) with greater flexibility and scalability than previous network generations.

The 5G Core Network is a cloud-native, service-based architecture where network functions (NFs) like the Access and Mobility Management Function (AMF), Session Management Function (SMF), and User Plane Function (UPF) offer their capabilities as reusable services to other authorized NFs via a common framework. Communication between these NFs uses HTTP/2-based service-based interfaces (SBIs). A key innovation is the clear separation of the User Plane (UP) from the Control Plane (CP). The UPF handles all packet routing and forwarding, policy enforcement, and traffic reporting, and it can be deployed flexibly and distributedly close to the network edge to minimize latency. The CP functions manage sessions, mobility, and policies.

5G introduces the concept of network slicing, which allows the creation of multiple logical, end-to-end networks on a shared physical infrastructure. Each slice is an isolated set of network resources and functions tailored to specific service requirements (e.g., enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), massive Machine-Type Communications (mMTC)). The 5G system supports a unified authentication framework and enables seamless mobility and session continuity, including interworking with 4G E-UTRAN via the Non-Standalone (NSA) architecture where the 5G RAN is anchored to a 4G core, and the Standalone (SA) architecture with a full 5G core.

Purpose & Motivation

5G was created to address the exponential growth in mobile data traffic and the emergence of new use cases that 4G networks were not designed to handle efficiently. The limitations of 4G included constrained peak data rates, higher latency unsuitable for real-time control, limited capacity for massive numbers of IoT devices, and a monolithic core network architecture that was difficult to adapt for diverse service requirements. The industry needed a more flexible, scalable, and efficient system to support the future digital society.

The primary motivation was to define a single, unified network platform capable of supporting three broad families of use cases defined by the ITU's IMT-2020 vision: Enhanced Mobile Broadband (eMBB) for extreme data rates, Ultra-Reliable Low-Latency Communications (URLLC) for critical applications like industrial automation and remote surgery, and massive Machine-Type Communications (mMTC) for connecting vast numbers of low-power sensors. This required a fundamental architectural shift to a cloud-native, service-based core and a more advanced radio interface.

Furthermore, 5G aims to reduce the total cost of ownership for operators by introducing network virtualization, softwarization, and automation. The service-based architecture and network slicing enable operators to deploy and manage services more rapidly and efficiently, creating new revenue streams by offering tailored connectivity solutions to vertical industries like automotive, manufacturing, and healthcare, which was challenging with previous generations.