5G Core Network

- Overview

5G Core (5GC) is the heart of a 5G mobile network. It establishes reliable, secure connectivity to the network for end users and provides access to its services. 

5GC implements the new 3GPP network architecture, which enables faster connectivity speeds, lower latency, and higher bit rates. It also enables network slicing, which is the ability to create multiple virtual networks that share the same physical infrastructure. 

Some essential elements for an optimized 5G core network include: 

• 5G Core application
• New automation capabilities
• Evolved security architectures
• New operations and lifecycle management
• Evolved cloud infrastructure
• 5G voice implementation across the network

5G Core implements the new 3GPP network architecture that will unlock the full capabilities of 5G standalone, enabling faster connection speeds, ultra-low latency, and higher bit rates and network reliability. 

These capabilities, combined with network automation, network slicing, and edge computing, help address multiple verticals and enable an ecosystem of innovations through use cases such as: Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), large-scale Machine Type Communication (mMTC) and Time Critical Communication (TCC). 

However, these new 5G networks will coexist with 4G networks for many years, while increasing efficiency is required to seize new opportunities.

- Core Components of 5G Networks

Here are some core components of 5G networks: 

• 5G core network: The central part of the 5G system that provides the main functions and services for the network. It's composed of cloud-native and service-based components that enable high scalability, flexibility, and efficiency.
• Access and mobility management function (AMF): A core network component in 5G that is responsible for managing access and mobility for 5G devices.
• External network infrastructure: A component of the solution stack that includes key network infrastructure capabilities such as security, load balancing, and datacenter fabric.
• User equipment (UE): The device that the user operates, such as a phone or a tablet.
• gNodeB (gNB): The base station that serves a geographical area, also known as a cell.
• Distributed unit (DU): A main component of the 5G RAN.

5G networks are designed to support edge computing, which involves processing data closer to the source rather than relying solely on centralized cloud servers. Multi-Access Edge Computing (MEC) nodes play a crucial role in enabling low-latency applications and services.

- 5G Core Service-Based Architecture (SBA)

5G architecture is an evolution of current 4G architectures but based on a Service-Based Architecture (SBA). The 3GPP defines the SBA for a 5G core network as delivered by a set of interconnected Network Functions (NFs), with authorization to access each other’s services.

The 5G 3GPP architecture relies on 5G Standalone (5G SA) New Radio and 5G Standalone Core (5G SA Core). Nokia's core architectural design is inherently cloud-native: its open, modular structure combined with 5G Services-Based Architecture (5G SBA) makes the introduction of future network capabilities feasible and allows rapid implementation and expansion of any functions, and wherever needed. Network functions are deployed as microservices, where business logic is delivered as small modular stateless services. 

5GC SA network functions can be moved to the edge of the network to meet the needs of new services and applications by providing an unprecedented level of automation in the end-to-end network to meet the low-latency needs of critical machine-type communications.

- NG-RAN, NGC and SBA

NG-RAN includes NR based 5G base stations called next generation node Bs or gNBs. A gNB can be decomposed or disaggregated into a central unit and a distributed unit. Such a gNB architecture reduces infrastructure and transport costs and provides scalability. While LTE uses a limited number of nodes in the evolved packet core (EPC), 5G defines more network functions (NF) that have fewer responsibilities. 

The overall 5G system is based on SBA, where NFs communicate with each other using service based interfaces. SBA facilitates the design and deployment of the 5G system using virtualization and automation technologies such as network functions virtualization (NFV), software defined networking (SDN), OpenStack and Orchestration.