Untrusted Access RAT Identification in 5G Core Registration

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Solution Overview

Problem

The 5G core network is unable to determine the specific type of untrusted non-3GPP access network used by a UE, leading to inadequate access control, service management, QoS control, and charging policies, as it only recognizes the access as 'Virtual' without precise identification.

Innovation Solution

The UE acquires access network information through DHCP or ANQP protocols and broadcasts, providing detailed Access Technology Type and Access Network Identity to the N3IWF, which forwards this information to the AMF to determine the specific Radio Access Type, enabling precise identification of the untrusted non-3GPP access network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the 5G core network uses a generic 'Virtual' access type for all untrusted non-3GPP access networks, then the system complexity is reduced and ease of operation is improved, but the measurement precision of access network identification deteriorates and service management capability is insufficient

Engineering Contradiction:
Improveease of operationVSAvoidmeasurement precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of access network identification from a generic 'Virtual' type to specific RAT types (NR, E-UTRA, WLAN) by introducing new information elements in the initial UE message. This allows the AMF to identify and differentiate between various untrusted access network types, enabling precise service management, QoS control, and charging policies while maintaining ease of operation through standardized protocol extensions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the 5G core network implements precise identification of untrusted access network types, then service management and QoS control are improved, but the device complexity and information processing requirements increase

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the N3IWF as an intermediary that collects access network information from the UE and forwards it to the AMF through the initial UE message. This intermediary approach allows precise identification of access network types without requiring complex processing at each node, as the information gathering and forwarding is handled by the N3IWF, simplifying the overall system architecture while improving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary action by having the UE provide access network information (such as ANI and ATT) to the N3IWF before the actual access establishment. This advance provision of information allows the AMF to determine the specific RAT type early in the registration process, enabling appropriate service management and QoS policies to be configured in advance, thereby improving reliability without adding complex real-time processing requirements.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If access network information is collected and processed through the N3IWF and AMF, then charging policies and service management are enhanced, but the loss of time for information processing and registration increases

Engineering Contradiction:
ImprovereliabilityVSAvoidloss of time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the access network information collection process with the existing registration procedure. The UE provides access network information (ANI, ATT) to the N3IWF, which is then included in the initial UE message sent to the AMF during registration. This merging eliminates separate information collection steps, allowing service management and charging policy configuration to occur concurrently with the registration process, thereby enhancing reliability without significant time loss.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4104549B1Determining an access network radio access type
Publication Date: 2026.04.01 LENOVO (SINGAPORE) PTE LTD
  • EP4104549B1 patent drawingFigure 1
  • EP4104549B1 patent drawingFigure 2A~2B
  • EP4104549B1 patent drawingFigure 2C

AI summary

Apparatuses, methods, and systems are disclosed for determining a RAT for an untrusted access network. One apparatus (400) includes a processor (405) and a transceiver (425) that communicates with a first access network. The processor (405) obtains (605) ANI about the first access network, the ANI including an access technology type for the first access network. The processor (405) determines (610) to register with a mobile communication network (e.g., a 5GC) via the first access network using an untrusted registration procedure and sends (615) a first request (e.g., an IKE_AUTH Request) to establish a secure connection with a N3IWF in the mobile communication network. Here, the first request includes a registration request for the mobile communication network and the obtained ANI, wherein the obtained ANI is used by the mobile communication network to determine a RAT for the first access network. Via the transceiver (625), the processor (605) receives (620) a response to the registration request after establishing the secure connection with the N3IWF, wherein the response depends on the RAT.