SMF Selection via QoS Mapping in 5G Roaming
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Solution Overview
Problem
The current SMF selection process in home-routed roaming cases for 5G networks is error-prone due to the mapping of NSSAIs or S-NSSAIs between visited and home networks, lacking a reliable method to ensure consistent Quality of Service (QoS) across different network slices.
Innovation Solution
The proposed solution involves using QoS information to select slices and NFs by introducing a mapping table and relying on the Access and Mobility Management Function (AMF) to transmit QoS requirements from the visited network to the home network, allowing the Home Network Repository Function (H-NRF) to pre-select candidate SMFs that meet these requirements, thereby eliminating the need for explicit S-NSSAI mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If NSSAI mapping between visited and home networks is used for SMF selection, then slice selection capability is provided, but mapping errors and reliability issues occur
Solution Approach 1:
The patent introduces QoS information as an intermediary parameter that mediates between the visited network's slice requirements and the home network's SMF selection. Instead of directly mapping NSSAIs which causes errors, the QoS information acts as a universal language that both networks can understand and use to make consistent selection decisions, thereby improving reliability while maintaining adaptability.
Solution Approach 2:
The patent changes the selection parameter from NSSAI (which is network-specific and mapping-prone) to QoS information (which is universal and error-resistant). By transforming the selection criterion from a network-specific identifier to a universal quality parameter, the system eliminates mapping errors while preserving the ability to select appropriate slices and SMFs.
2Stability of the object's composition
If explicit S-NSSAI mapping is implemented between VPLMN and HPLMN, then slice correspondence is established, but administrative burden and error-prone processes increase
Solution Approach 1:
The patent extracts the problematic S-NSSAI mapping process from the SMF selection procedure and replaces it with QoS-based selection. By removing the mapping step entirely and keeping only the essential slice correspondence requirement, the system maintains stability in slice selection while eliminating the complex and error-prone mapping administration.
Solution Approach 2:
Instead of creating complex mapping relationships between different network slices, the patent uses QoS information as a common copy or representation that both visited and home networks can use independently. This universal representation eliminates the need for explicit mapping while preserving the essential correspondence between slices across networks.
3Adaptability or versatility
If multiple SMF selection criteria (NSSAI, DNN, subscription info) are considered, then comprehensive selection is achieved, but selection process complexity increases
Solution Approach 1:
The patent merges multiple selection criteria (NSSAI, DNN, subscription information) into a unified QoS-based selection process. By combining these previously separate considerations into a single QoS parameter framework, the system maintains comprehensive selection capability while reducing the complexity of evaluating and coordinating multiple independent criteria.
Data Source
AI summary
Upon receiving (S10) a request in a visited network in which a UE is roaming, an SMF selection function (10) of the visited network selects an H-SMF located in a home network of the UE by transmitting (S20) information indicating requirements towards an H-NRF (20) located in the home network, receiving (S40), based on the transmission of the information, at least one candidate H-SMF complying with the requirements, and selecting (S50) the H-SMF from the at least one candidate H-SMF.