LADN Policy-Based PDU Session Establishment for Roaming UEs

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In next-generation mobile communication, user equipment (UE) faces challenges in establishing Protocol Data Unit (PDU) sessions over Local Area Data Networks (LADN) during roaming, particularly due to the lack of subscription information for LADN Data Network Names (DNN) in visited networks, which prevents service access despite the use of wildcard DNNs.

Innovation Solution

A method is introduced where the UE requests and receives LADN policies from the Access and Mobility Management Function (AMF), determining the appropriate LADN DNN based on the received policy, which includes information such as Single Network Slice Selection Assistance Information (S-NSSAI), Session and Service Continuity mode, and PDU session type, to establish a PDU session.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If UE uses wildcard DNN during roaming, then service access is enabled, but LADN PDU session establishment fails due to lack of subscription information

Engineering Contradiction:

Improveservice access capabilityVSAvoidLADN PDU session establishment reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The AMF acts as an intermediary between the UE and the LADN DNN selection process. It receives the PDU session establishment request with wildcard DNN, determines the appropriate LADN DNN based on UE location and subscription information, and forwards the request with the determined DNN to the SMF, enabling successful session establishment

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary determination of the LADN DNN by the AMF before the PDU session establishment request reaches the SMF. This advance resolution of the DNN selection problem prevents the failure that would occur if the SMF tried to process a wildcard DNN without proper subscription information

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If UE requests LADN policy during roaming, then correct LADN DNN can be determined, but additional signaling overhead is introduced

Engineering Contradiction:

ImproveLADN DNN determination accuracyVSAvoidsignaling time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The UE selectively requests LADN policy information only when needed (e.g., during roaming or when LADN service is required), rather than continuously. This partial action approach obtains the necessary precision for LADN DNN determination without incurring unnecessary signaling overhead during normal operations

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11470657B2Method, user equipment, and network node for performing PDU session establishment procedure for LADN

Publication Date: 2022.10.11 LG ELECTRONICS INC

AI summary

One disclosure of the present specification provides a method by which a user equipment (UE) performs a protocol data unit (PDU) session establishment procedure for a local area data network (LADN). The method comprises: when a pre-set condition related to an LADN policy is satisfied, transmitting a message requesting an access and mobility management function (AMF) for the LADN policy; receiving, from the AMF, the LADN policy provided by a policy control function (PCF), wherein the LADN policy comprises information about at least one application and information about a LADN data network name (DNN) related to the at least one application; determining a LADN DNN to be used by the UE, on the basis of the LADN policy; and transmitting a PDU session establishment request message related to the determined LADN DNN to the AMF.