5G NR NSSAA Mode Switching to Avoid Futile Slice Reselection

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing Network Slice Specific Authentication and Authorization (NSSAA) procedures, leading to unnecessary reselections and inefficiencies when network slices are unavailable, resulting in battery drain and delayed service availability.

Innovation Solution

Implementing mechanisms to disable N1 mode when no network slices are available, allowing UEs to prioritize LTE or other available networks, thereby avoiding futile NR cell reselections and enabling quicker service access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If UE continues to attempt NR mode registration and cell reselection when network slices are unavailable, then service availability is delayed and battery drains, but network utilization remains suboptimal

Engineering Contradiction:
Improveservice availability timeVSAvoidbattery consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The UE performs preliminary determination of network slice availability before initiating full registration procedures. By checking whether supported network slices are actually available in the current registration area, the UE can preemptively avoid futile registration attempts and unnecessary cell reselections, thereby saving time and battery energy while maintaining service availability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the UE reports network slice availability status to the network side, and the network provides feedback information about slice availability in different registration areas. This feedback loop enables both UE and network to make informed decisions about mode selection, avoiding wasted registration attempts and optimizing overall service deployment.

Inventive Principle:
Principle #23Feedback

2Productivity

If UE disables N1 mode when no network slices are available, then battery consumption reduces and service availability improves, but network complexity increases

Engineering Contradiction:
Improveservice access speedVSAvoidnetwork management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the operational mode between N1 and N0 based on real-time network slice availability conditions. The UE can switch between modes depending on whether supported slices are available, creating a flexible and adaptive system that optimizes performance while managing complexity through conditional logic rather than rigid fixed-state architecture.

Inventive Principle:
Principle #15Dynamics

3Reliability

If UE performs NR cell reselection to find available network slices, then service quality improves, but unnecessary reselections occur causing battery drain

Engineering Contradiction:
Improveservice qualityVSAvoidbattery drain from reselection
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The UE determines in advance whether network slices are available in the current registration area before initiating cell reselection procedures. This preliminary check prevents the UE from performing unnecessary NR cell reselections when slices are not available, thereby saving battery energy while still enabling high-quality service access when slices are present.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4154610B1Network slice specific authentication and authorization (NSSAA) 5g new radio (NR) procedures
Publication Date: 2026.03.04 APPLE INC
  • EP4154610B1 patent drawingFigure 1
  • EP4154610B1 patent drawingFigure 2
  • EP4154610B1 patent drawingFigure 3

AI summary

Disclosed are embodiments for disabling N1 mode in response to several scenarios including an S-NSSAI failure, searching NR PLMNs after a loss of coverage in an attempt to maintain network slices, and triggering a UE to reattempt authentication of a rejected S-NSSAI when authentication credentials change and the UE either has N1 mode enabled or is camped on LTE PLMN that might be the same as the NR PLMN through which the S-NSSAI was rejected.