URSP Rule Matching for S-NSSAI and PDU Session Reuse
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Solution Overview
Problem
Existing 5G wireless communication systems face challenges in efficiently handling UE route selection policy (URSP) for PDU sessions due to issues like duplicated sessions, signaling overhead, and suboptimal selection of PDU sessions, particularly when there are mismatches in Single-Network Slice Selection Assistance Information (S-NSSAI) and PDU session types.
Innovation Solution
A method for enhanced URSP rule matching that allows exceptions in S-NSSAI and PDU session type associations, enabling the reuse of existing PDU sessions even when there are parameter mismatches, by allowing certain deviations from exact matches in S-NSSAI and PDU session types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE strictly matches URSP rules requiring exact S-NSSAI and PDU session type correspondence, then the accuracy of session selection is improved, but the signaling overhead increases due to rejected sessions and the system loses flexibility in reusing existing sessions
Solution Approach 1:
The patent modifies the matching parameters by introducing flexibility in S-NSSAI and PDU session type correspondence. Specifically, it allows URSP rule matching to succeed even when S-NSSAI values differ or when PDU session types are compatible but not identical (e.g., IPv4v6 matching IPv4 or IPv6). This parameter relaxation enables existing sessions to be reused without triggering new session establishment signaling, thereby reducing signaling overhead while maintaining adequate session selection accuracy.
Solution Approach 2:
The patent segments the matching criteria into essential and non-essential components. S-NSSAI and PDU session type are treated as non-essential for exact matching in certain contexts, allowing the matching process to focus on more critical parameters like DNN and session state. This segmentation enables selective application of strict matching where needed and flexible matching where session reuse is beneficial, balancing accuracy and signaling efficiency.
2Reliability
If the UE establishes new PDU sessions for all applications without reusing existing sessions, then the reliability of session establishment is improved, but the device complexity increases due to multiple duplicated sessions
Solution Approach 1:
The patent enables existing PDU sessions to serve multiple applications by relaxing the matching criteria. A single PDU session established for one application can be reused by other applications that match the same URSP rule, even with different S-NSSAI or PDU session types. This multi-functionality reduces the total number of sessions required, simplifying session management while maintaining reliable connectivity for each application through the shared session infrastructure.
3Manufacturing precision
If the UE applies strict URSP matching rules, then the manufacturing precision of session configuration is improved, but the adaptability of the system to different network conditions deteriorates
Solution Approach 1:
The patent introduces dynamic matching behavior that adapts to different network conditions and session states. The matching strictness is adjusted based on whether existing sessions are available and their compatibility with current application requirements. When compatible existing sessions exist, flexible matching enables reuse; when no suitable sessions exist, the system can establish new sessions with precise configuration. This dynamic approach balances configuration precision with adaptability to varying network scenarios.
Data Source
AI summary
A method for UE route selection policy (URSP) rule matching regarding S-NSSAI and PDU session type is proposed. When an application is executed, a UE finds an RSD of a matching URSP rule, and the association of the application with an existing PDU session should have some exceptions. In one example, regarding S-NSSAI, if there's only a single allowed S-NSSAI or the UE is aware of the default S-NSSAI, the UE can associate the PDU session with the application where the existing PDU session is established with an S-NSSAI provided by the UE, but the RSD doesn't include any S-NSSAI. In another example, regarding PDU session type, the PDU session type IPv4v6 in the RSD can match with PDU session type IPv4 or IPv6 of the PDU session, which was established when the UE requested IPv4v6 during the PDU session establishment.