5G core network essentials

5G networks were deployed from 2019 and will represent the dominant mobile network technology for the decade 2020-2030. Compared with the previous 4G generation, which was focused on transporting IP flows, most often with no guarantee of quality of service, 5G aims to foster new deployment scenarios to cover very diverse market segments and thus meet the needs of an ultra-connected society. This is made possible by declining a 5G system into multiple forms, each aiming to specialize on a few quality-of-service criteria from a well-defined list.

Although the transport of data flows in 5G remains based on the principles of 4G, the main breakthrough in terms of the core network is the extensive use of web technologies for signaling exchange. The network is made up of a set of network functions, each specialized on a limited number of tasks. All dialogues take place in client-server mode and are stateless. Coupled with the principles of virtualization, this makes for a flexible network that can adapt to variations in load or type of services used. Instances of network functions can be started and stopped, and any instance can discover active instances meeting certain criteria by querying a directory function. In addition, a 5G network offers access to external service providers who can develop value-added services by interacting with user terminals. All these elements are described in this article.