UE Category Notification for Reliable LTE Attach and Switching

Solution Overview

Problem

Existing methods for determining the category of user equipment (UE) in LTE networks, such as Cat.M, are unreliable when the UE can switch between categories after attaching to the core network, leading to inconsistent charging and service policies.

Innovation Solution

A user equipment (UE) with an attach processing unit, operation control unit, and category notification unit to reliably notify the core network of its operating category, and network devices like MME with category reception and transfer units to manage and process this information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the eNB determines the UE category based on cell type and notifies the core network, then the core network can identify Cat.M devices, but the notification becomes unreliable when the UE switches categories after attaching

Engineering Contradiction:

Improvecategory notification reliabilityVSAvoidUE category switching capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The UE includes its operating category information in the attach request message before attaching to the core network. This preliminary action ensures that the core network receives accurate category information at the time of attachment, resolving the reliability issue while allowing the UE to switch categories later by sending updated notifications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The UE actively monitors its operating category and sends category notification messages to the core network when category switching occurs after attachment. This feedback mechanism ensures the core network always has up-to-date category information, maintaining reliability despite UE category switching capability.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If the UE switches categories after attaching to the core network, then the UE can adapt to different service requirements, but the existing notification method cannot cope with category switching

Engineering Contradiction:

ImproveUE category switching capabilityVSAvoidcategory information accuracy

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The UE includes its operating category information in the attach request message before attaching to the core network. This preliminary action ensures that the core network receives accurate category information at the time of attachment, resolving the reliability issue while allowing the UE to switch categories later by sending updated notifications.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The UE actively monitors its operating category and sends category notification messages to the core network when category switching occurs after attachment. This feedback mechanism ensures the core network always has up-to-date category information, maintaining reliability despite UE category switching capability.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If the UE includes category information in attach request, then the core network receives accurate category information, but the UE must actively monitor and notify category changes

Engineering Contradiction:

Improvecategory information accuracyVSAvoidcategory monitoring and notification mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The UE autonomously determines its own operating category based on its capability and the serving cell type, and automatically sends category notification messages to the core network when category switching occurs. This self-service approach eliminates the need for complex external monitoring mechanisms while maintaining accurate category information.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The UE actively monitors its operating category and sends category notification messages to the core network when category switching occurs after attachment. This feedback mechanism ensures the core network always has up-to-date category information, maintaining reliability despite UE category switching capability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12520127B2User equipment, network device, and radio communication method

Publication Date: 2026.01.06 NTT DOCOMO INC

AI summary

A UE 200 operates as any one of a plurality of categories according to capability. The UE 200 includes: an attach processing unit 220 that performs attaching to a core network; an operation control unit 230 that causes the UE 200 to operate as a restricted category whose capability is restricted as compared to a normal category; and a category notification unit 240 that notifies the core network of a category in which the UE 200 is operating at the time of the attaching or after the attaching.