UE Timer Handling for Rejected S-NSSAI After NSSAA Failure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Network slice-specific authentication and authorization (NSSAA) failures can prevent data transmission, especially in devices that are difficult to recover from errors, such as those unable to turn off power or release the USIM, leading to temporary communication disruptions.
Innovation Solution
A user equipment (UE) receives a configuration update command with timer information for NSSAA failure, adding rejected S-NSSAI and deleting it after the timer expires, allowing re-use of the S-NSSAI after a certain time without moving to a new PLMN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the NSSAA procedure is performed for a specific network slice, then authentication and authorization are improved, but communication reliability deteriorates when temporary failures occur in devices that cannot reset
Solution Approach 1:
The patent introduces dynamic timer-based management of rejected NSSAI, allowing the system to transition from a static rejection state to a dynamic state where S-NSSAI can be automatically removed from the rejected list after timer expiration. This enables temporary failures to be recovered without device reset, resolving the contradiction between authentication reliability and data transmission capability.
Solution Approach 2:
The patent changes the parameter state of rejected NSSAI by introducing time-based validity. Instead of permanent rejection, the system now tracks rejection duration through timers, allowing parameters to change from rejected to accepted state automatically. This resolves the contradiction by maintaining authentication integrity while enabling recovery from temporary failures.
2Reliability
If the UE performs full initialization to recover from NSSAA failure, then error recovery is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the essential recovery mechanism from full initialization by selectively removing only the rejected S-NSSAI from the rejected NSSAI list after timer expiration, rather than performing complete UE initialization. This extracts the minimal necessary action for error recovery, reducing complexity while maintaining reliability.
Solution Approach 2:
The system performs self-service error recovery through automatic timer-based removal of rejected NSSAI without requiring user intervention or full device reset. The UE autonomously manages its own error recovery state, simplifying the process while maintaining reliability.
3Reliability
If the rejected S-NSSAI is permanently stored, then authentication security is improved, but adaptability deteriorates when temporary failures occur
Solution Approach 1:
The patent implements periodic action through timers that automatically expire and trigger re-evaluation of rejected NSSAI. This periodic time-based action maintains security by not immediately accepting previously rejected S-NSSAI, while ultimately enabling adaptability through automatic removal from the rejected list, allowing recovery from temporary failures.
Solution Approach 2:
The system provides beforehand cushioning by maintaining a timed rejection state rather than permanent rejection. This cushioning period protects against immediate re-attempt of failed authentication while allowing automatic recovery, balancing security with adaptability for temporary failures.
Data Source
AI summary
Provided are a method and a device for processing network slice selection assistance information (NSSAI) rejected due to a network slice-specific authentication and authorization (NSSAA) failure. A user equipment (UE) receives a UE configuration update command message from an access and mobility management function (AMF). On the basis of failure of NSSAA with respect to single NSSAI (S-NSSAI0, the UE configuration update command message includes time information related to a timer. The UE adds the S-NSSAI to a rejected NSSAI, starts the timer on the basis of the time information, and deletes the S-NSSAI included in the rejected NSSAI after the timer expires.