5G NSA, or 5G Non-Standalone, refers to an initial deployment approach of 5th generation mobile networks (5G) that relies on the existing 4G LTE infrastructure for certain core network functionalities. In a 5G NSA deployment, the new 5G radio access network (RAN) is introduced, while the core network relies on the existing 4G LTE core. This approach allows for a faster rollout of 5G services, leveraging the capabilities of both 4G and 5G technologies. Here are the key aspects of 5G NSA:
- Dual Connectivity:
- Concept: 5G NSA introduces dual connectivity, where a user device simultaneously connects to both 4G LTE and 5G networks. This enables a seamless transition between the two technologies based on network conditions and the availability of 5G coverage.
- EN-DC (E-UTRA-NR Dual Connectivity):
- Integration: The E-UTRA-NR Dual Connectivity standard specifies the mechanisms for dual connectivity between 4G LTE (E-UTRA) and 5G NR (New Radio). This standard ensures efficient cooperation between the two technologies, optimizing the use of available resources.
- LTE as the Anchor:
- Core Network Dependency: In 5G NSA, the 4G LTE core network serves as the anchor for control plane functionalities. While the user plane benefits from 5G NR, control plane signaling and management rely on the existing LTE infrastructure.
- Faster Time to Market:
- Advantages: The 5G NSA approach allows operators to deploy 5G services more quickly since it leverages the existing 4G core network. This is particularly advantageous for early 5G rollouts, enabling operators to provide enhanced mobile broadband (eMBB) services sooner.
- Transition Phase:
- Evolutionary Path: 5G NSA is considered a transitional phase in the evolution towards a fully standalone 5G architecture. It allows for the introduction of 5G capabilities while minimizing the need for extensive modifications to the existing core network.
- Limited 5G Core Functionalities:
- Core Network Features: While 5G NSA introduces the new 5G RAN, certain advanced core network features associated with 5G, such as network slicing and the full set of 5G core functions, may not be fully realized until the transition to 5G SA (Standalone).
- Dynamic Resource Allocation:
- Resource Management: 5G NSA enables dynamic resource allocation between 4G and 5G, ensuring that users experience optimal performance based on the available network conditions and the specific requirements of their applications.
- Coexistence with 4G Services:
- Smooth Transition: 5G NSA allows for a smooth coexistence with existing 4G services, ensuring that users with both 4G and 5G devices can access mobile services seamlessly. This coexistence is essential during the early phases of 5G deployment.
- Evolution to 5G SA:
- Future Transition: 5G NSA is considered an intermediate step towards the eventual deployment of 5G SA. As the 5G ecosystem matures, operators may transition to a fully standalone architecture to unlock the full potential of 5G core functionalities.
5G NSA represents a pragmatic approach for operators to introduce 5G services swiftly while maximizing the benefits of existing 4G infrastructure. It allows for a gradual evolution toward a complete 5G standalone architecture, providing a balance between speed to market and long-term network evolution.