RRC Inactive UE RNA Update Signaling Overhead

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Solution Overview

Problem

In 5G wireless communication networks, RRC_INACTIVE state UEs can move out of their configured RAN notification area without notification, leading to failed paging procedures and increased overhead in UE context transfer and RNA updates, which hinders quick reestablishment of RRC connections.

Innovation Solution

A method for UE-initiated RNA updates that inform the anchor gNB of the UE's movement, allowing for efficient RNA configuration management and quick RRC connection resumption, using RRCConnectionResumeRequest with causeValue 'ranNotificationAreaUpdateRequest' and delta-signaling for RNA updates, ensuring minimal signaling and resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the UE moves out of the configured RNA without notification, then the UE can maintain RRC_INACTIVE state with minimal signaling, but the RAN cannot locate the UE leading to failed paging procedures

Engineering Contradiction:
Improvepower consumptionVSAvoidpaging procedure reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the UE proactively notifies the RAN when it moves out of the configured RNA by initiating an RNA update procedure. This feedback ensures the RAN maintains accurate UE location information without requiring continuous monitoring, thus reducing power consumption while maintaining paging reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having the UE perform RNA updates before the RAN would need to page the UE. By proactively notifying the RAN of location changes, the UE ensures that paging procedures will succeed without requiring the UE to continuously monitor or the RAN to perform extensive location searches.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the RAN performs frequent UE context transfer and RNA updates to track UE movement, then the UE location accuracy is maintained, but the signaling overhead and resource costs increase

Engineering Contradiction:
ImproveUE location accuracyVSAvoidsignaling overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements periodic action through event-triggered RNA updates that occur at specific moments when the UE moves out of its configured RNA, rather than continuously. This approach maintains location accuracy by updating when necessary while avoiding unnecessary periodic updates that would increase signaling overhead.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies self-service by enabling the UE to autonomously determine when it has moved out of its configured RNA and to initiate the RNA update procedure itself. This eliminates the need for the RAN to continuously monitor UE location or perform frequent context transfers, significantly reducing signaling overhead while maintaining accurate location tracking.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the RNA is configured to be small to improve location precision, then the UE location accuracy increases, but the frequency of RNA updates and context transfers increases

Engineering Contradiction:
Improvelocation precisionVSAvoidmobility management efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies dynamics by making the RNA configuration flexible and adaptive. The RAN can configure RNAs of different sizes based on UE mobility patterns and service requirements. For low-mobility UEs, smaller RNAs provide precise location tracking without excessive updates, while for high-mobility UEs, larger RNAs reduce update frequency. The system dynamically adjusts RNA boundaries and triggers updates only when UEs cross RNA boundaries.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the UE initiates RNA updates to notify the anchor gNB of movement, then the RAN location accuracy is maintained, but the signaling overhead increases

Engineering Contradiction:
ImproveRAN location accuracyVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies the taking out principle by extracting only the essential location update information and transmitting it efficiently. When the UE initiates an RNA update, it provides concise information about its new location, and the RAN only performs the minimal necessary context transfer or configuration update. This extracts only the necessary signaling elements, maintaining reliability while minimizing overhead.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3711363B1Radio access network notification area configuration and management
Publication Date: 2024.03.27 FG INNOVATION CO LTD
  • EP3711363B1 patent drawingFigure 1
  • EP3711363B1 patent drawingFigure 2a~2e
  • EP3711363B1 patent drawingFigure 3A~3B

AI summary

A method of Radio Access Network (RAN) Notification Area (RNA) management for a user equipment (UE) is disclosed. The method includes receiving, by the UE, a first Radio Resource Control (RRC) message having a first Radio Access Network (RAN) Notification Area (RNA) configuration; storing, by the UE, the first RNA configuration, when the UE is in an RRC Connected state, an RRC Inactive state, or a transition between the RRC Inactive state and the RRC Connected state; and applying, by the UE, an RNA update procedure, based on the first RNA configuration when the UE is in the RRC Inactive state.