UE NSSAI Storage Updates for 5G Slice Access Control
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Solution Overview
Problem
The implementation method for managing the number of User Equipments (UEs) allowed for each network slice in the 5G System (5GS) is not clear, hindering effective network slicing management.
Innovation Solution
A User Equipment (UE) is equipped with a transmission and reception unit to receive allowed Network Slice Selection Assistance Information (NSSAI) and a controller to delete mapped Single Network Slice Selection Assistance Information (S-NSSAI) from rejected NSSAI stored in the storage unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE stores rejected NSSAI information for network slice management, then the network can track and control UE access to specific slices, but the storage and management complexity of NSSAI information increases
Solution Approach 1:
The network performs preliminary actions by providing mapping relationships between home PLMN S-NSSAIs and visited PLMN S-NSSAIs in advance through configuration update commands. This allows the UE to automatically resolve mapped S-NSSAIs when encountering rejected NSSAI during roaming, eliminating the need for complex manual configuration and reducing storage burden while ensuring reliable slice management.
Solution Approach 2:
The mapping relationship between home PLMN S-NSSAIs and visited PLMN S-NSSAIs acts as an intermediary mechanism. When the UE encounters a rejected S-NSSAI during roaming, it uses this mapping relationship to identify the corresponding home PLMN S-NSSAI, which then guides the UE's reconnection attempt. This intermediary approach simplifies the UE's decision-making process while maintaining reliable network slice management.
2Adaptability or versatility
If the UE deletes mapped S-NSSAI from rejected NSSAI after receiving allowed NSSAI, then the network can enable UE reconnection to previously rejected slices, but the risk of connection loops or conflicts increases
Solution Approach 1:
The UE dynamically manages the rejected NSSAI list by automatically deleting mapped S-NSSAIs upon receiving allowed NSSAI information. This dynamic adjustment allows the UE to adapt its connection behavior based on current network conditions and authorization status, enabling flexible reconnection to previously rejected slices while maintaining connection stability through systematic updates.
Solution Approach 2:
The system implements feedback mechanisms where the UE monitors its connection status and automatically updates the rejected NSSAI list based on received allowed NSSAI information. When the UE receives permission to access a slice that was previously rejected, it automatically removes the corresponding mapped S-NSSAI from the rejected list, creating a feedback loop that ensures connection stability while enabling adaptive reconnection.
3Measurement precision
If the network provides mapping relationships for S-NSSAI between home PLMN and visited PLMN, then roaming slice selection accuracy improves, but the signaling overhead and configuration complexity increase
Solution Approach 1:
The mapping relationship configuration serves multiple functions simultaneously: it enables accurate slice selection during roaming, provides the basis for automatic rejected NSSAI resolution, and supports both initial network selection and reconnection scenarios. This multi-functionality reduces the need for separate signaling mechanisms, thereby lowering overall signaling overhead while maintaining high slice selection accuracy.
Data Source
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AI summary
A User Equipment (UE) includes a transmission and reception unit, a controller, and a storage unit. The transmission and reception unit receives allowed Network Slice Selection Assistance Information (NSSAI). The controller deletes mapped Single Network Slice Selection Assistance Information (S-NSSAI) of the allowed NSSAI from rejected NSSAI stored by the storage unit.