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non standalone 5g architecture

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Let's delve into the technical details:

1. Core Network:

In NSA 5G, the core network (often referred to as the 5G Core or 5GC) is designed to support both 4G LTE and 5G radio access networks (RAN). The 5GC introduces a service-based architecture (SBA), which allows for more modular and scalable service delivery.

2. 4G LTE eNodeB:

The existing 4G LTE base stations (eNodeBs) are utilized to anchor the connection for the user equipment (UE). When a UE initiates a communication session, it connects through the LTE eNodeB, even if it wants to use 5G services.

3. Dual Connectivity:

To provide a seamless user experience and combine the capabilities of both 4G and 5G networks, dual connectivity is used. In this setup, the UE is simultaneously connected to both the LTE eNodeB and the 5G new radio (NR) base station (gNodeB). The LTE connection serves as the anchor while 5G provides additional bandwidth and capabilities.

4. Control Plane and User Plane Separation:

The 5G architecture introduces a separation between the control plane (CP) and the user plane (UP). This separation allows for more efficient network management, scalability, and flexibility. In NSA mode, the 5GC controls the user sessions while leveraging the 4G LTE UP for data forwarding.

5. Network Functions:

The 5GC consists of various network functions (NFs) that handle specific tasks, such as:

  • AMF (Access and Mobility Management Function): Manages access and mobility for UEs.
  • SMF (Session Management Function): Handles session establishment, modification, and release.
  • UPF (User Plane Function): Responsible for packet routing and forwarding in the user plane.
  • NRF (NF Repository Function): Provides information about available NFs in the network.

6. RAN Sharing:

In NSA deployments, operators can share the 5G RAN resources with existing 4G infrastructure. This approach enables a more cost-effective rollout of 5G services by utilizing the existing infrastructure where possible.

7. Transition to Standalone (SA):

While NSA provides a rapid deployment option for 5G, the ultimate goal for most operators is to transition to a standalone (SA) 5G architecture. In SA mode, the 5GC operates independently of the 4G LTE core, offering the full capabilities and benefits of 5G without relying on legacy infrastructure.