UE NAS Timer Adjustment for Extended Coverage Access Reliability

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Solution Overview

Problem

User Equipment (UE) faces challenges in accurately setting Non-Access Stratum (NAS) timers due to uncertainty about Enhanced Coverage (EC) mode restrictions, leading to potential initial access failures.

Innovation Solution

The UE dynamically adjusts NAS timers based on determining operation in wideband and supporting EC restrictions by transmitting an access request message to a network entity, receiving an acceptance message indicating the EC restriction status, and applying the identified duration to initiate the NAS timer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the UE uses a fixed NAS timer duration for EC restriction, then the network can maintain stable control, but the system cannot adapt to varying EC restriction patterns leading to unnecessary camp-on failures

Engineering Contradiction:
ImproveAdaptability to varying EC restriction patternsVSAvoidReliability of camp-on procedure
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of the NAS timer duration based on historical EC restriction data. The UE transitions from using a fixed timer to a dynamic timer that adapts its duration according to the frequency and pattern of EC restrictions experienced in the geographic area, thereby resolving the contradiction between adaptability and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the UE monitors and stores historical EC restriction information from multiple PLMNs in a geographic area. This feedback loop allows the UE to adjust the NAS timer duration based on accumulated experience, improving adaptability while maintaining reliability through data-driven decisions.

Inventive Principle:
Principle #23Feedback

2Speed

If the UE transmits access request messages frequently to check EC restriction status, then the UE can quickly adapt to restriction changes, but this increases signaling overhead and network load

Engineering Contradiction:
ImproveSpeed of adapting to EC restriction changesVSAvoidSignaling overhead and energy consumption
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by having the UE proactively determine and store historical EC restriction data for multiple PLMNs in advance, before actually needing to access the network. This preparation allows the UE to make informed decisions about NAS timer duration without requiring frequent access request messages, thus reducing signaling overhead while maintaining fast adaptation capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts the NAS timer duration based on stored historical data, allowing the UE to optimize the balance between adaptation speed and signaling frequency. By making the timer dynamic rather than fixed, the system achieves fast adaptation when needed while avoiding unnecessary signaling during stable periods.

Inventive Principle:
Principle #15Dynamics

3Speed

If the UE applies a short NAS timer duration, then the UE can quickly respond to EC restriction changes, but this increases the frequency of camp-on failures in restricted areas

Engineering Contradiction:
ImproveResponse speed to EC restriction changesVSAvoidSuccess rate of camp-on procedure
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements a dynamic NAS timer that adjusts its duration based on the specific PLMN and historical EC restriction patterns. Instead of using a uniformly short timer, the system selectively applies shorter durations only when historical data indicates low EC restriction frequency for a particular PLMN, while using longer durations when restrictions are frequent, thus maintaining both speed and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by customizing the NAS timer duration for each specific PLMN based on its individual EC restriction history in the geographic area. Rather than applying a global timer setting, the system tailors the timer characteristics to local conditions, ensuring optimal performance for each network operator's specific restriction patterns.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4415428B1Techniques for user equipment (UE) dynamically adjusting a non-access stratum (NAS) timer in a wireless communication system
Publication Date: 2026.04.29 QUALCOMM INC
  • EP4415428B1 patent drawingFigure 1
  • EP4415428B1 patent drawingFigure 2
  • EP4415428B1 patent drawingFigure 3

AI summary

The present disclosure relates to a user equipment (UE) dynamically adjusting a non-access stratum (NAS) timer. Specifically, the UE may determine operation in a wideband and support of an extended coverage (EC) restriction. The UE may further identify a duration of a non-access stratum (NAS) timer based on determining operation in the wideband and the EC restriction. The UE may further transmit an access request message to a network entity to trigger a mobility management procedure. The UE may further receive an acceptance message from the network entity indicating an unrestricted or restricted status of the EC restriction. The UE may further apply the duration to the NAS timer based on the acceptance message indicating the unrestricted or restricted status of the EC restriction received from the network entity or a history of EC restrictions of a public land mobile network (PLMN) in a defined geographic area.