UE URSP Rule Evaluation for 5G PDU Session Access
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Solution Overview
Problem
In 5G New Radio (NR) systems, the behavior of User Equipment (UE) regarding the application of access type preferences during UE Route Selection Policy (URSP) rules evaluation for establishing or matching PDU sessions is not defined, leading to inefficiencies in traffic management and session establishment.
Innovation Solution
A method where the UE evaluates non-default URSP rules with matching traffic descriptors, selects a route selection descriptor that includes a preferred access type or multi-access preference, and either matches or establishes a PDU session by ignoring or using this preference, progressing to default rules if necessary, to determine the appropriate access type for PDU session association or establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE strictly follows the preferred access type in route selection descriptor, then the network can control the access type preference, but the UE behavior is not defined and leads to inefficiencies in traffic management and session establishment
Solution Approach 1:
The patent applies dynamics by making the UE's application of access type preferences flexible rather than rigid. The UE can dynamically choose to either apply or ignore the preferred access type based on current network conditions and session requirements, allowing adaptive behavior that resolves the contradiction between reliable session establishment and efficient traffic management.
Solution Approach 2:
The patent changes the parameter of access type preference application from a fixed state to a variable state. By allowing the UE to modify its behavior regarding access type preference application, the system transitions from an undefined static state to a controlled dynamic state, improving both reliability and operational efficiency.
2Measurement precision
If the UE evaluates all non-default URSP rules before applying default rules, then the matching accuracy improves, but the evaluation time and complexity increase
Solution Approach 1:
The patent applies preliminary action by having the UE pre-identify and prioritize non-default URSP rules that contain matching traffic descriptors. This preliminary filtering step allows the UE to focus evaluation efforts on the most relevant rules first, achieving high matching accuracy while reducing overall evaluation time by avoiding unnecessary checks of all rules.
Solution Approach 2:
The patent segments the URSP rule evaluation process into distinct phases: first evaluating non-default rules with specific traffic descriptors, then falling back to default rules only if necessary. This segmentation allows the system to achieve precise matching through structured evaluation while minimizing time loss by limiting the scope of comprehensive evaluation to only when required.
Data Source
AI summary
A method for evaluation of UE route selection policy (URSP) rules is proposed. URSP is used by a UE to determine if a detected application can be associated to an established PDU session, can be offloaded to non-3GPP access outside a PDU session, or can trigger the establishment of a new PDU session. The UE first finds a non-default URSP rule with a matching traffic descriptor to the application. Then, the UE selects a route selection descriptor including a preferred access type from a list of RSDs of the non-default URSP rule. After that, the UE matches or establishes a Protocol Data Unit (PDU) session for the application by ignoring the preferred access type or using the preferred access type.