URSP Rule Matching for Redundant PDU Session Reliability

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Solution Overview

Problem

In 5G wireless communication systems, the behavior of User Equipment (UE) is undefined when establishing redundant PDU sessions over non-3GPP access, leading to potential failures and user experience degradation due to unsupported Ultra Reliable and Low Latency Communication (URLLC) applications.

Innovation Solution

A method for enhanced User Equipment (UE) route selection policy (URSP) rule matching is proposed, where the UE ignores route selection descriptors (RSDs) with 'PDU session pair ID type' or 'RSN type' components if they include 'multi-access preference type' or 'preferred access type' set to 'non-3GPP access', ensuring redundant PDU sessions are established only over 3GPP access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE attempts to establish redundant PDU sessions over non-3GPP access, then the adaptability of the system is improved, but the reliability deteriorates due to undefined UE behavior and potential establishment failures

Engineering Contradiction:
ImproveadaptabilityVSAvoidreliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extracts and removes the problematic route selection descriptors (RSDs) that contain conflicting components (PDU session pair ID type or RSN type combined with multi-access preference type or preferred access type set to non-3GPP access). By taking out these invalid RSD configurations, the system prevents undefined UE behavior while maintaining adaptability for valid redundant PDU session establishment over 3GPP access.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of allowing the UE to attempt establishment and then handling failures, the patent inverts the approach by proactively identifying and ignoring invalid RSD configurations before PDU session establishment attempts. This prevents the reliability issue by stopping the process before undefined behavior can occur.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If the UE establishes redundant MA PDU sessions with non-3GPP access leg, then the versatility of the system is improved, but the reliability deteriorates due to unexpected results in URLLC application packet transmission

Engineering Contradiction:
ImproveversatilityVSAvoidreliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent removes multi-access preference type or preferred access type components from RSDs that are intended for redundant PDU sessions. This extraction prevents the creation of redundant MA PDU sessions with non-3GPP access legs, thereby avoiding the reliability issues associated with URLLC packet transmission while preserving the ability to establish redundant sessions over 3GPP access.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies preliminary anti-action by preemptively ignoring RSDs with conflicting components before the PDU session establishment process begins. This prevents the system from entering a state where redundant MA PDU sessions with non-3GPP access could cause unexpected results, thereby protecting URLLC application reliability.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If the UE ignores RSDs with conflicting components, then the reliability of redundant PDU session establishment is improved, but the device complexity increases due to additional URSP rule matching logic

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent enables the URSP rule matching mechanism to self-identify and filter out invalid RSD configurations through built-in logical checks. The UE autonomously determines whether an RSD contains conflicting components (PDU session pair ID type or RSN type combined with multi-access preference type or preferred access type) and ignores such RSDs without requiring external intervention, thereby managing the increased complexity through self-service validation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the behavioral parameter of the UE during URSP rule matching by introducing a conditional filter that detects and ignores RSDs with specific conflicting component combinations. This parameter change in the matching logic enables reliable redundant PDU session establishment while the complexity is managed through systematic parameter validation rather than ad-hoc handling.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4161153A1URSP procedure enhancement for redundant PDU session
Publication Date: 2023.04.05 MEDIATEK INC
  • EP4161153A1 patent drawingFigure 1~2
  • EP4161153A1 patent drawingFigure 3~4
  • EP4161153A1 patent drawingFigure 5

AI summary

A method for route selection policy (URSP) rule matching supporting redundant PDU session is proposed. When an application is executed, the upper layer of a UE sends the application information to URSP entity for matching a URSP rule. The UE selects and evaluates a route selection descriptor (RSD) from a list of RSDs of a selected URSP rule to be matched with a PDU session. If there is a "PDU session pair ID type" or "RSN type" route selection descriptor component in an RSD, and there is also "multi-access preference type" descriptor component, or a "preferred access type" descriptor component set to "non-3GPP access" in the same RSD, UE ignores the RSD since it is invalid for a redundant PDU session.