SOR-AF Roaming Status Update via Access Type

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Solution Overview

Problem

Current 3GPP specifications lack a mechanism for the Steering of Roaming Application Function (SOR-AF) to decide on updates to Steering of Roaming (SOR) information based on UE roaming status events and deliver this information through control plane signaling, and do not include the access type used by the UE to access the serving PLMN, which is necessary for generating updated SOR information.

Innovation Solution

A method where the SOR-AF receives roaming status reporting information from the Unified Data Management (UDM), generates updated SOR information including the access type, and transmits this information to the UDM, which then relays it to the UE via the Access and Mobility Management Function (AMF), allowing for event-based updates and optimizing roaming steering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the HPLMN UDM provides SOR information to the UE based on operator policy during initial registration, then the roaming steering capability is established, but there is no mechanism for dynamic updates based on UE roaming status events

Engineering Contradiction:

Improvedynamic SOR information update capabilityVSAvoidsystem mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The SOR-AF subscribes to UE roaming status events in advance through the UDM, establishing a proactive mechanism that automatically triggers SOR information updates when roaming status changes occur, rather than waiting for periodic requests or manual interventions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback loop where the UDM notifies the SOR-AF of UE roaming status events, which then generates updated SOR information and delivers it back to the UE through control plane signaling, creating a closed-loop adaptive system

Inventive Principle:

Principle #23Feedback

2Loss of information

If the roaming status report contains basic PLMN information, then the roaming status can be tracked, but the access type information needed for generating updated SOR information is missing

Engineering Contradiction:

Improveaccess type information completenessVSAvoidSOR information generation efficiency

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The system preemptively collects and includes access type information (3GPP access, non-3GPP access) in the roaming status reports sent from UDM to SOR-AF, so that all necessary input data for SOR information generation is available when needed, eliminating delays caused by information requests

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240414619A1Methods and systems for steering of roaming

Publication Date: 2024.12.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method (600) performed by a Steering of Roaming Application Function, SOR-AF. The method includes receiving a roaming status reporting notify message from a Unified Data Management, UDM. The notify message comprises roaming status reporting information including a new serving Public Land Mobile Network, PLMN, Identifier, an access type of a User Equipment for accessing the new serving PLMN identified by the PLMN Id, and a roaming indication indicating the new serving PLMN is different from the Home PLMN or not. The method further includes generating an updated steering of roaming information based on the received roaming status reporting information including at least the access type; and transmitting to the UDM a parameter provision update request message. The update request message comprises the updated steering of roaming information.