S-NSSAI Mapping for Roaming Slice Selection
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Solution Overview
Problem
In the 5G mobile communication system, there is a challenge in interpreting and matching the network slice selection assistance information (S-NSSAI) requested by a user equipment (UE) during roaming, as the visited PLMN may not recognize or correctly interpret the S-NSSAI values provided by the UE, leading to potential mismatches in slice selection and services.
Innovation Solution
A mapping or association between the requested S-NSSAI and the S-NSSAI used in the visited PLMN (vS-NSSAI) is established, with the UE pre-configured with subscribed S-NSSAIs and their corresponding slice indexes, allowing the UE to correlate and provide the correct slice index for network slice selection, ensuring correct slice selection and service provisioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE provides S-NSSAI values configured for HPLMN during roaming, then the UE can request network slices it is subscribed to, but the VPLMN may not recognize or correctly interpret these S-NSSAI values, leading to slice selection mismatches
Solution Approach 1:
The patent introduces an intermediary mapping mechanism where the UE maintains a mapping between HPLMN S-NSSAIs and VPLMN S-NSSAIs. When roaming, the UE uses this mapping to translate requested S-NSSAIs from HPLMN values to VPLMN-compatible values, ensuring the VPLMN can correctly interpret and fulfill the slice selection while the UE still requests its subscribed slices.
Solution Approach 2:
The patent changes the parameter representation of S-NSSAI by introducing a mapping relationship between HPLMN S-NSSAI and VPLMN S-NSSAI. The UE transforms the S-NSSAI parameter from its HPLMN-specific form to a VPLMN-recognized form through the mapping, allowing the same logical slice request to be expressed in a different parameter format that the visited network understands.
2Ease of operation
If the VPLMN uses its own S-NSSAI values for slice selection, then the VPLMN can correctly manage its network slices, but the UE cannot guarantee it receives the specific subscribed slices from HPLMN
Solution Approach 1:
The mapping mechanism acts as an intermediary that connects VPLMN's native S-NSSAI system with HPLMN's subscribed S-NSSAI system. The VPLMN continues to use its own S-NSSAI values for slice management without change, while the mapping ensures these values correspond to the UE's subscribed slices, maintaining both VPLMN operational simplicity and subscription fulfillment reliability.
Solution Approach 2:
The patent creates a universal mapping mechanism that works across different PLMNs. The mapping table in the UE provides a universal translation layer that allows the same HPLMN S-NSSAI to map to different VPLMN S-NSSAIs depending on the roaming partner, making the solution universally applicable across multiple roaming scenarios while maintaining slice subscription fidelity.
3Productivity
If the UE stores and uses PLMN-specific Configured NSSAI, then the UE can optimize slice selection for each PLMN, but the complexity of managing and updating NSSAI configurations across multiple PLMNs increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the mapping between HPLMN S-NSSAIs and VPLMN S-NSSAIs in the UE before roaming. This mapping is established in advance through network provisioning, so when the UE roams to a VPLMN, it can immediately use the pre-established mapping without complex real-time configuration management, reducing device complexity while maintaining slice selection efficiency.
Data Source
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AI summary
A method for registering a UE in a visited network. The method includes the UE selecting a home network slice identity (h-NSI), wherein the h-NSI is associated with an index value. The method also includes the UE obtaining the index value with which the selected h-NSI is associated, and after obtaining the index value, the UE transmitting a registration message towards a control node, the registration message comprising a requested NSI (r-NSI) (e.g., an S- NSSAI) and the obtained index value. The method further includes the UE receiving a registration response message comprising an allowed NSI (a-NSI) and an index value associated with the a-NSI.