DRX Mode TTT Timer Disabling for UE Handover Control

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Solution Overview

Problem

In enhanced Universal Terrestrial Radio Access Network (E-UTRAN), the use of Discontinuous Reception (DRX) mode for user equipment leads to mobility challenges, especially in high-velocity scenarios and small cells, due to reduced measurement requirements, which can result in unnecessary handovers and increased signaling resources when there are no active data transmissions.

Innovation Solution

Disabling the Time-To-Trigger (TTT) timer in user equipment during inactive data reception periods prevents measurement reports from being sent to the network, thereby inhibiting handovers to target cells like small cells when there are no active data transmissions, thus conserving signaling resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If DRX mode is applied during inactive data reception, then user equipment power saving is improved, but measurement reporting frequency decreases leading to unnecessary handovers

Engineering Contradiction:
Improveuser equipment power savingVSAvoidhandover accuracy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent dynamically adjusts the Time-To-Trigger timer behavior based on the DRX state of the user equipment. When DRX is active during inactive periods, the TTT timer is disabled to prevent measurement reports from being triggered. When DRX is not active or during active data reception, the TTT timer operates normally. This dynamic adaptation resolves the contradiction by making the measurement reporting behavior contingent on the power saving state, ensuring reliable handovers only when necessary.

Inventive Principle:
Principle #15Dynamics

2Use of energy by moving object

If DRX mode is applied during inactive data reception, then user equipment power saving is improved, but signaling overhead increases due to unnecessary handovers

Engineering Contradiction:
Improveuser equipment power savingVSAvoidsignaling overhead
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent implements dynamic control of measurement reporting by disabling the Time-To-Trigger timer when DRX is active during inactive data reception. This prevents measurement reports from being generated and sent to the network, thereby eliminating unnecessary signaling overhead while maintaining power saving benefits. The TTT timer is re-enabled when DRX is not active or during active data reception, ensuring normal measurement reporting functionality when needed.

Inventive Principle:
Principle #15Dynamics

3Reliability

If measurement reports are continuously sent in DRX mode, then handover accuracy is improved, but signaling overhead increases

Engineering Contradiction:
Improvehandover accuracyVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent dynamically adjusts measurement reporting behavior based on the operational state of the user equipment. During inactive data reception in DRX mode, the Time-To-Trigger timer is disabled, preventing measurement reports from being sent and reducing signaling overhead. During active data reception or when DRX is not applied, the TTT timer operates normally, ensuring accurate handover decisions. This dynamic approach optimizes the balance between handover accuracy and signaling overhead.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2946593B1Inhibiting the transmission of measurement reports from a ue when the ue is in an inactive mode and applies drx
Publication Date: 2020.02.19 NOKIA TECHNOLOGIES OY
  • EP2946593B1 patent drawingFigure 1
  • EP2946593B1 patent drawingFigure 2A
  • EP2946593B1 patent drawingFigure 2B

AI summary

Methods and apparatus, including computer program products, are provided for determining whether a user equipment is in an inactive connected mode, i.e. applies discontinuous reception DRX mode, during a period of inactive data reception; and disabling a timer for triggering a measurement report at the user equipment, when the user equipment applies DRX mode, wherein the disabled timer inhibits the measurement report related to a target cell from being sent by the user equipment. Related apparatus, systems, methods, and articles are also described.