UE NSSAI Mapping for Roaming in Stand-Alone Non-Public Networks

Solution Overview

Problem

There is no clear implementation method for supporting Network Slice Selection Assistance Information (NSSAI) functions in Stand-alone Non-Public Networks (SNPNs) within the 5G System (5GS), which are essential for managing network slices and sessions for various terminals and services.

Innovation Solution

A User Equipment (UE) is equipped with a transmission and/or reception unit and a controller that replaces pending NSSAI with mapped S-NSSAI during roaming, and stores the mapped S-NSSAI, disregarding the current PLMN's S-NSSAI, to support network slice functions in SNPNs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE stores and uses pending NSSAI from the core network, then network slice selection capability is improved, but during roaming the S-NSSAI mapping becomes complex and may cause conflicts with current PLMN slices

Engineering Contradiction:

Improvenetwork slice selection capabilityVSAvoidS-NSSAI mapping complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The UE performs preliminary mapping of pending S-NSSAI to current PLMN S-NSSAI before actual network slice usage. The controller replaces pending NSSAI with mapped S-NSSAI in advance, ensuring that when network slice services are accessed during roaming, the mapping is already established and no real-time conversion conflicts occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a mapping relationship as an intermediary layer between the core network's pending NSSAI and the current PLMN's S-NSSAI. This mapping table acts as a mediator that translates between different network slice identification systems, allowing the UE to maintain compatibility with both the home network's slice configuration and the visited network's slice structure without direct conflict.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the UE supports network slice functions in SNPNs, then service functionality is improved, but the implementation method becomes unclear and increases deployment difficulty

Engineering Contradiction:

Improveservice functionalityVSAvoiddeployment ease

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent makes the UE's network slice handling mechanism universal by applying the same pending NSSAI storage, mapping, and replacement logic regardless of whether the UE is connected to a public network or a standalone non-public network (SNPN). The controller automatically adapts the slice management process to the current network type, eliminating the need for separate implementation methods for different network scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the UE disregards current PLMN S-NSSAI during roaming, then network slice conflicts are reduced, but the loss of local network slice information may affect service quality

Engineering Contradiction:

Improvenetwork slice conflict reductionVSAvoidlocal network slice information

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The UE performs preliminary mapping of pending S-NSSAI to current PLMN S-NSSAI before actual network slice usage. The controller replaces pending NSSAI with mapped S-NSSAI in advance, ensuring that when network slice services are accessed during roaming, the mapping is already established and no real-time conversion conflicts occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a mapping relationship as an intermediary layer between the core network's pending NSSAI and the current PLMN's S-NSSAI. This mapping table acts as a mediator that translates between different network slice identification systems, allowing the UE to maintain compatibility with both the home network's slice configuration and the visited network's slice structure without direct conflict.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250330894A1User equipment (UE) and communication control method performed by ue

Publication Date: 2025.10.23 SHARP KK

AI summary

Provided are, in the 5GS, a method and a communication mechanism for procedures of initial registration of a UE and a periodic or mobility-based registration for implementing management of information about network slice or non-public network function. Furthermore, provided are a method and a communication mechanism for a deregistration procedure after completion of the registration procedure. Furthermore, provided is a method for managing information about network slice in association with each procedure and state transition. Accordingly, provided is, in the 5GS, a communication mechanism for implementing a function related to management of information about network slice or non-public network function.