UE NAS Transport Handling for TAI Change and Slice Support
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Solution Overview
Problem
Existing wireless communication systems face challenges in effectively processing non-access stratum (NAS) messages, particularly when uplink (UL) NAS transport messages fail due to changes in tracking area identifiers (TAI) or unsupported Single Network Slice Selection Assistance Information (S-NSSAI), leading to potential abortion of NAS transport procedures.
Innovation Solution
A method and device for a User Equipment (UE) to initiate an NAS transport procedure, detect transmission failures due to TAI changes, and determine whether to abort the procedure based on comparisons with a TAI list, considering support for S-NSSAI and lower layer reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continues to transmit UL NAS transport messages after TAI change, then the NAS transport procedure may be aborted, but the transmission reliability deteriorates
Solution Approach 1:
The UE performs preliminary actions by detecting TAI changes and comparing changed TAI with stored TAI list before transmitting UL NAS transport messages. This preliminary detection and comparison prevents unnecessary transmissions to unsupported TAI, avoiding procedure abortion while maintaining reliability without adding complex processing during message transmission.
2Productivity
If the UE aborts NAS transport procedure upon TAI change, then the system efficiency improves, but the message delivery reliability deteriorates
Solution Approach 1:
The UE implements feedback mechanism by continuously monitoring TAI changes and comparing with stored TAI list. When TAI change is detected and the changed TAI is not in the stored list, the UE aborts the NAS transport procedure with appropriate notification. This feedback loop enables efficient system response while maintaining reliable message delivery by preventing futile transmissions to unsupported TAI.
3Adaptability or versatility
If the UE supports partial network slice, then the network slice selection flexibility improves, but the NAS message processing complexity increases
Solution Approach 1:
The UE segments the network slice selection process by maintaining separate data structures for allowed S-NSSAI and supported TAI. The UE processes NAS messages by checking S-NSSAI against allowed list and TAI against supported list independently, then combines these checks for final decision. This segmentation enables flexible network slice selection while managing processing complexity through structured, modular checks.
Data Source
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AI summary
The present disclosure relates to an apparatus and a method for processing a non-access stratum (NAS) message in a wireless communication system, wherein the method performed by a terminal may comprise the steps of: initiating a NAS transport procedure; detecting a failure to transmit an uplink (UL) NAS transport message due to a change in a tracking area identifier (TAI); comparing the changed TAI with a TAI list; and determining whether to stop the NAS transport procedure on the basis of the result of the comparison.