Why was this decision made? Basically, the implementation of the 5G NSA network was designed to speed up the introduction of the first 5G services through an intermediate configuration that facilitated the reuse of existing 4G infrastructure.
However, the high performance and variety of services specified by the ITU for 5G networks in its IMT-2020 documents required significant improvements in the network infrastructure, both in radio access and in the core network.
In this regard, the 5G SA configuration features a fully independent 5G core network, which no longer requires a 4G connection to manage signalling. This enables advanced 5G features that facilitate the commercial launch of new use cases.
Both architectures are included within the 5G framework, however, their designs and features are significantly different from each other. Both NSA and SA are labelled as 5G standards, but the full benefits of 5G will not be realised until 5G SA is commercially available.
Network architecture
As mentioned above, the main difference between 5G NSA and 5G SA lies in their architecture. While 5G NSA retains the 4G EPC (Evolved Packet Core) for control and signalling management, 5G SA implements a completely new architecture, featuring a native 5G core based on cloud-native principles, NFV (Network Functions Virtualisation) and SDN (Software Defined Networking).
Latency and performance
As in 5G NSA, the 4G network remains as the anchor, latency is limited by the need to perform management control through the LTE core. For this reason, despite enabling improvements in speed and capacity, 5G NSA does not achieve the ultra-low latency promised by 5G.
In contrast, 5G SA, already operating with a dedicated 5G core, enables minimal latency times and more effective management of traffic essential for critical applications.
Enabled services
5G NSA technology focuses primarily on providing greater bandwidth for streaming or browsing services, but does not include advanced features such as network slicing or URLLC (ultra-reliable low-latency communications) natively.
However, 5G SA technology, with its native 5G network core, already enables more advanced services such as:
- Network slicing: establishment of customised virtual networks on a shared physical infrastructure.
- MEC (Multi-access Edge Computing): use of edge processing to reduce latency to a minimum.
- URLLC and mMTC (massive machine-type communications): used for large-scale IoT connectivity and critical communications.
Deployment and maturity
5G NSA has been the starting point for numerous commercial launches as its simplicity has enabled faster and more cost-effective deployment, perfectly suited to quickly cover urban and rural areas.
However, the implementation of 5G SA requires a more comprehensive network transformation, involving investments in core infrastructure and new interfaces. Despite this, it represents the path to achieving full maturity of the 5G ecosystem.
Device compatibility
5G NSA-compatible devices can operate using the 4G network as an anchor, which has facilitated the rapid availability of 5G devices on the market.
In contrast, 5G SA requires clear compatibility with the 5G core. Not all current devices offer the possibility of software upgrades, which limits access to SA-exclusive services.
Interfaces and protocols
In 5G NSA, the key interfaces are the X2 interface (between the eNB and the gNB) or the S1 interface (towards the EPC). Dual Connectivity (EN-DC) is used to combine 4G and 5G carriers. In 5G SA, the model is based on the 3GPP 5G reference architecture, which introduces concepts such as SMF (Session Management Function) and UPF (User Plane Function).
Conclusion
Both architectures represent complementary phases in the development of 5G. 5G NSA has driven rapid commercial deployment, while 5G SA unlocks the full potential of this new generation of mobile networks. As the industry evolves, the transition to 5G SA is emerging as the next strategic milestone to drive new business models, improve network efficiency and address next-generation use cases.
