URSP Rule Matching for PDU Session Reuse

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Solution Overview

Problem

In 5G new radio (NR) systems, the current UE route selection policy (URSP) fails to efficiently reuse existing PDU sessions when network-assigned parameters differ from requested parameters, leading to duplicated sessions, signaling overhead, or suboptimal route selection.

Innovation Solution

The method enhances URSP rule matching by allowing the UE to associate with existing PDU sessions when either the requested or stored parameters match the route selection descriptors of the selected URSP rule, even with exceptions, enabling efficient reuse of existing sessions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE strictly matches requested parameters with stored PDU session parameters, then parameter matching precision is improved, but PDU session reuse efficiency deteriorates

Engineering Contradiction:

Improveparameter matching precisionVSAvoidPDU session reuse efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the matching parameter criteria from requiring exact match between requested parameters and stored PDU session parameters to allowing partial matching. Specifically, the UE now matches RSD parameters against either requested parameters or stored parameters of existing PDU sessions, relaxing the strict parameter equality constraint to enable broader session reuse while maintaining adequate matching quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the parameter matching process into two independent comparison paths: one comparing RSD parameters against requested parameters, and another comparing RSD parameters against stored PDU session parameters. This segmentation allows the system to evaluate multiple matching possibilities without requiring a single strict match, thereby improving session reuse efficiency while maintaining matching precision through multiple validation points.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the UE reuses existing PDU sessions with parameter mismatches, then PDU session reuse efficiency is improved, but route selection optimality deteriorates

Engineering Contradiction:

ImprovePDU session reuse efficiencyVSAvoidroute selection optimality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the UE evaluates whether an existing PDU session can be reused by checking if RSD parameters match against stored session parameters. When a match is found, the system provides feedback to confirm session reuse. This feedback loop ensures that parameter mismatches are systematically evaluated and resolved, maintaining route selection optimality while enabling efficient session reuse through structured validation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies partial matching action by allowing RSD parameters to match against stored PDU session parameters even when not all parameters exactly match. This partial matching approach enables session reuse under relaxed conditions, improving efficiency while the system still performs adequate validation to ensure route selection remains sufficiently optimal for the application requirements.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If the UE establishes new PDU sessions for all applications, then route selection accuracy is improved, but signaling overhead increases

Engineering Contradiction:

Improveroute selection accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by having the UE check for existing PDU sessions and their stored parameters before establishing new sessions. The system pre-evaluates whether an existing session can be reused by comparing RSD parameters against stored parameters, and only establishes new sessions when necessary. This preliminary checking mechanism reduces unnecessary session establishment signaling, lowering overhead while maintaining route selection accuracy through selective new session creation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent merges the parameter matching function with the existing PDU session selection process. Instead of separate operations for parameter validation and session selection, the system combines these functions by integrating RSD parameter matching directly into the session reuse decision logic. This merging eliminates redundant signaling operations and streamlines the session management process, reducing overhead while preserving route selection accuracy.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20230052670A1Enhancement of URSP association

Publication Date: 2023.02.16 MEDIATEK INC

AI summary

A method for UE route selection policy (URSP) rule matching enhancement 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 finds an RSD of the matching URSP rule, and the UE tries to reuse an existing PDU session, e.g., the association of the application with the existing PDU session have certain exceptions. In one example, regarding DNN, S-NSSAI, SSC mode, and PDU session type, the above listed parameters in the RSD can either match with stored PDU session parameters of the existing PDU session or match with PDU session parameters requested by the UE during the PDU session establishment procedure.