UE Rejected NSSAI Storage by Access Type for Service Continuity

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Solution Overview

Problem

Existing 5G mobile communication systems face disruptions due to the disconnection of ongoing services when Single Network Slice Selection Assistance Information (S-NSSAI) is rejected due to the maximum number of UEs reached, leading to service discontinuity across different access types.

Innovation Solution

The User Equipment (UE) maintains a separate list of rejected S-NSSAI for each access type, allowing it to manage and prevent disruptions by identifying and storing rejected S-NSSAI information based on the access type, and performing actions accordingly to avoid service disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the UE maintains a single rejected NSSAI list without differentiation by access type, then the storage and management of rejected S-NSSAI information is simplified, but service continuity is disrupted when S-NSSAI is rejected due to maximum number of UEs reached on one access type

Engineering Contradiction:
Improverejected NSSAI list management complexityVSAvoidservice continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the rejected NSSAI list into separate lists for each access type (3GPP access and non-3GPP access). When an S-NSSAI is rejected on one access type due to maximum number of UEs reached, the rejection is stored only in the corresponding access type's list, allowing the same S-NSSAI to be attempted on other access types without being affected by the rejection on the first access type.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the UE applies rejected S-NSSAI information across all access types, then the number of rejected S-NSSAI to track is reduced, but future service requests are hampered by unnecessary rejections on other access types

Engineering Contradiction:
Improvenumber of rejected S-NSSAI to trackVSAvoidservice request flexibility across access types
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The patent segments the rejection tracking by creating access type-specific rejected NSSAI lists. This allows the UE to track rejections separately for 3GPP and non-3GPP access types, enabling flexible service requests on different access types even when rejections occur on one specific access type.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by making the rejection information specific to each access type context. The rejected NSSAI list for 3GPP access is distinct from the rejected NSSAI list for non-3GPP access, allowing each access type to have its own quality characteristics regarding rejection handling.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If the UE disconnects ongoing services when S-NSSAI is rejected due to maximum number of UEs reached, then the network resource allocation is optimized, but service discontinuity occurs across different access types

Engineering Contradiction:
Improvenetwork resource efficiencyVSAvoidservice duration
Core Design Contradiction:
Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent segments the service management by access type, allowing services to continue on one access type even when rejected on another. When S-NSSAI is rejected on non-3GPP access, the UE maintains the service on 3GPP access by not applying the rejection from the non-3GPP list to the 3GPP service.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent ensures continuity of useful action by maintaining separate rejected NSSAI lists for each access type. This allows the UE to continue services on one access type while handling rejections on another access type independently, preventing unnecessary service discontinuity.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4179787B1Method for user equipment storing rejected network slice selection assistance information per access type
Publication Date: 2026.02.11 SAMSUNG ELECTRONICS CO LTD
  • EP4179787B1 patent drawingFigure 1
  • EP4179787B1 patent drawingFigure 2
  • EP4179787B1 patent drawingFigure 3

AI summary

A method and system in the User Equipment (UE) for maintaining rejected network slice selection assistance information (NSSAI) for Single Network Slice Selection Assistance Information (S-NSSAI) not available due to maximum number of UEs reached per access type. The method comprises receiving a Non-Access Stratum (NAS) message including at least one of a registration accept, registration reject or CONFIGURATION UPDATE COMMAND message along with at least one of rejected Single Network Slice Selection Assistance Information (S-NSSAI(s)) information and a cause for the S-NSSAI not available due to maximum number of UEs reached from a network. Thereafter, the method includes determining by the UE an access type on which the rejected S-NSSAI(s) is applicable based on the received S-NSSAI (s) information and then maintaining a storage of the rejected NSSAI for the S-NSSAI not available due to the maximum number of the UEs reached per access type based on the determination.