V-SMF Home-Routed PDU Session Establishment

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Solution Overview

Problem

In 5G networks, establishing a user-requested PDU session during home-routed roaming is hindered by the visited PLMN's lack of necessary information about the corresponding HPLMN function, leading to difficulties in exchanging information and authenticating/authorizing the user's data session.

Innovation Solution

The proposed solution involves methods and procedures for a session management function in the visited PLMN to request and receive identifiers associated with resources in the home PLMN, enabling timely and controlled updates to facilitate correct operation during PDU session establishment, including early delivery or delayed response mechanisms to address authentication/authorization challenges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the visited PLMN establishes a PDU session during home-routed roaming using conventional procedures, then the session establishment process is initiated, but the visited PLMN lacks necessary information about the corresponding HPLMN function, leading to information exchange failures

Engineering Contradiction:
ImprovePDU session establishment success rateVSAvoidInformation about HPLMN function
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The V-SMF requests and receives the identifier of the HPLMN resource before completing the PDU session establishment. This preliminary action ensures that the visited PLMN has the necessary information about the HPLMN function in advance, preventing information exchange failures during session setup.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The identifier of the HPLMN resource acts as an intermediary that bridges the visited PLMN and home PLMN systems. This identifier enables the V-SMF to correctly interact with HPLMN resources without needing complete information about HPLMN internal functions, resolving the information asymmetry problem.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the visited PLMN waits for complete authentication information from HPLMN before establishing PDU session, then authentication accuracy is improved, but session establishment time increases

Engineering Contradiction:
ImproveAuthentication accuracyVSAvoidSession establishment time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The V-SMF requests the identifier of the HPLMN resource preliminarily during session establishment before completing authentication. This allows the authentication process to proceed in parallel with session setup procedures, reducing overall establishment time while maintaining accuracy through subsequent verification steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The authentication process is made dynamic by allowing session establishment to proceed with preliminary information, then updating and verifying authentication details subsequently. This dynamic approach balances speed and accuracy by adapting the authentication depth to the current stage of session establishment.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4057656B1Efficient PDU session establishment for home routed roaming
Publication Date: 2024.08.14 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP4057656B1 patent drawingFigure 1
  • EP4057656B1 patent drawingFigure 2A~2C
  • EP4057656B1 patent drawingFigure 3~4

AI summary

Exemplary embodiments include a method, performed by a session management function (V-SMF) of a visited public land mobile network (VPLMN), for establishing a user-requested PDU session to be routed through the user's home PLMN (HPLMN). Such embodiments include receiving, from an access management function (AMF) in the HPLMN, a first request to establish a home-routed PDU session, wherein the first request identifies an SMF (H-SMF) in the HPLMN. Such embodiments also include sending, to the H-SMF, a second request to create the home-routed PDU session. The second request can include an identifier of a resource in the V-SMF associated with the PDU session; and one or more indicators of whether the V-SMF supports respective one or more features related to receiving, from the H-SMF, an identifier of a resource in the H-SMF that is associated with the PDU session. Embodiments also include complementary methods performed by the H-SMF.