Increased network capabilities, along with the advent of new functionalities, have allowed the network to evolve from a 5G NSA (Non Stand Alone) network to a 5G SA (Stand Alone) network in recent years.
The first 5G
5G NSA was the first 5G architecture standardised by 3GPP, based on the deployment of 5G radio stations controlled by the existing 4G network core. This 5G NSA configuration was designed to deploy the first 5G services, however, the high performance and variety of simultaneous services set out by the ITU for 5G networks in its IMT-2020 documents are only possible by making significant improvements to the network, both at the radio access and core network level. In this sense, the 5G SA configuration already incorporates a new 5G network core, in which a 4G connection is no longer necessary for signalling management and where network functions are already completely virtualised. This allows automating its management and deploying services and resources in a scalable and efficient way, in order to offer the advanced 5G functionalities that will enable the commercial deployment of new use cases.
One of the main novelties of the 5G SA network is network segmentation, also known as Network Slicing. Network Slicing refers to the end-to-end(E2E) network architecture that allows several customised virtual networks to be created on the same common physical infrastructure. This allows different operators to offer networks as a service(Network as a Service) to customers and companies.
It is true that, as of today, there are already some solutions based on 5G NSA networks, or even LTE, that allow the allocation of network resources through the use of identifiers, such as resource partitioning (RRP), quality of service (QoS), public land mobile network (PLMN), etc. However, it should be noted that the potential of Network Slicing multiplies the possibilities for flexibility of infrastructure use and resource allocation with respect to these solutions, as it is a concept unique to 5G SA networks.
Services
Broadly speaking, within the Network Slicing concept, each virtual network (slice) encompasses an independent set of logical network functions that support the requirements of a specific application or service. This functionality has been standardised in 3GPP as one of the core functionalities of 5G SA networks, where four key service types have been defined:
- Enhanced Mobile Broadband (eMBB). These are enhanced mobile broadband services related to user experience, allowing, for example, the delivery of ultra high definition (UHD) content, virtual reality (VR) applications and augmented reality (AR) experiences. This is currently the only slice that is supported in the network and for which mobile terminals currently exist.
- Ultra Reliable Low Latency Communications (uRLLC). These are highly reliable, low latency communications. They allow very low latency connections and increase network availability up to 99.99% of the time, enabling uninterrupted communications with terminals moving at speeds of up to 500 km/h.
- Massive Machine Type Communication (mMTC). mMTC communications offer connectivity for the internet of things (IoT) and will increase capacity to support a higher density of connected devices. It is the evolution of the current NB-IoT and LTE-M.
- Vehicle to everything (V2X). Connected mobility, currently in the standardisation phase.
Definition
A 5G SA network slice is defined by the S-NSSAI (Single Network Slice Selection Assistance Information) identifier. The S-NSSAI is composed of the SST (Slice Service Type), and the SD (Slice Differentiator) field.
The SST field indicates the service type of the slice and is standardised in 3GPP according to the service to which it corresponds:
- SST 1 for eMBB services
- SST 2 for uRLLC services.
- SST 3 for mMTC services.
- SST 4 for V2X services.
The SD field is used to identify the different network slices belonging to the same type of service.
The fact that the S-NSSAI identifier is defined transversally in all network planes allows the slicing concept to work from the connection establishment phase until the end of data transmission.
The use cases
Telefónica has already conducted a number of pilots to demonstrate the possibilities of the Network Slicing architecture. One of them is a 5G pilot in the leisure and tourism sector, making the Hotel Meliá Madrid Serrano the first in Spain with indoor 5G NSA, 5G SA and Network Slicing coverage. For this pilot, several slices were configured to guarantee service for different connectivity needs, such as video streaming services even in times of saturation of guests or visitors.
Today, Telefónica is still working on the development of new services based on this technology, related to critical communications, vehicular communications, drones…, as well as on the evolution of existing services such as private networks (mobile networks that are set up for a single customer with elements that are exclusively dedicated to them).
As we can guess, this is only a small foretaste of the developments that this new network architecture will bring with it. The progressive transformation and evolution of the network makes it possible to gradually offer these new capabilities. In the future, Network Slicing technology, together with the capacity of Telefónica’s 5G network, will be key to digital transformation, enabling latency-critical applications such as those related to medicine and health.
References:
- (1) Innovación Telefónica España (Nov. 2023). Network Slicing: Technology, motivation and use cases.
- (2) CNMC (March 2023). 5G technology monitoring report. Part 1.
- https://www.cnmc.es/sites/default/files/5234822.pdf
- (3) 3GPP Portal (Jul. 2023). 5G Network slice management.
- https://www.3gpp.org/technologies/slice-management
- (4) Telefónica Spain. 5G use cases: First hotel in Europe with 5G SA connectivity and Network slicing over public network.
