DAPS Handover RLF Reporting for Threshold Optimization

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Solution Overview

Problem

Current communication systems, particularly in New Radio (NR) and Long Term Evolution (LTE) systems, face challenges in managing Radio Link Failure (RLF) during Dual Active Protocol Stack (DAPS) handovers, leading to potential data interruption and suboptimal handover processes.

Innovation Solution

A wireless communication method where a terminal device reports RLF occurrences to the network device, allowing for optimization of measurement event thresholds, thereby ensuring effective DAPS handover configurations and reducing data interruption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If DAPS handover is implemented to reduce interruption time, then handover speed is improved, but reliability of handover process deteriorates due to RLF occurrence in source cell

Engineering Contradiction:
Improvehandover speedVSAvoidhandover reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the terminal device monitors RLF conditions in the source cell during DAPS handover and reports this information to the network device. The network device uses this feedback to adjust measurement thresholds and configure appropriate handover parameters, creating a closed-loop control system that improves handover reliability while maintaining speed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts measurement event thresholds and handover parameters based on the reported RLF conditions. The network device modifies measurement thresholds, power offset values, and other parameters according to the RLF report type and measurement results, optimizing the handover process for both speed and reliability under different radio conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If measurement thresholds are optimized to prevent RLF, then handover reliability is improved, but handover speed deteriorates due to additional measurement and reporting overhead

Engineering Contradiction:
Improvehandover reliabilityVSAvoidhandover speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies partial action by implementing RLF monitoring and reporting only during the specific DAPS handover process when needed, rather than continuously. The terminal device performs RLF detection and reporting selectively based on handover state, reducing unnecessary measurement overhead while maintaining reliability where it matters most.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary configuration of measurement parameters and thresholds before the handover executes. The network device pre-configures measurement events, reporting criteria, and threshold values based on historical RLF data and current network conditions, allowing the handover to proceed smoothly without real-time adjustments that would slow it down.

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If RLF reporting mechanism is implemented to improve handover reliability, then information accuracy is improved, but device complexity increases due to additional monitoring and reporting functions

Engineering Contradiction:
Improveinformation accuracyVSAvoiddevice complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent extracts the RLF monitoring and reporting function as a separate, dedicated mechanism within the terminal device. Rather than integrating RLF detection into general radio resource management, the system implements a specific RLF report type with dedicated measurement and reporting procedures, making the function modular and easier to manage despite added complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent designs the RLF reporting mechanism to serve multiple purposes: it provides feedback for threshold optimization, identifies handover failure causes, and enables network-side adjustments for future handovers. This multi-functionality justifies the added device complexity by delivering comprehensive handover optimization benefits.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4161151B1Wireless communication methods, terminal device, and network device
Publication Date: 2024.06.26 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4161151B1 patent drawingFigure 1~3
  • EP4161151B1 patent drawingFigure 4~6
  • EP4161151B1 patent drawingFigure 7~9

AI summary

Embodiments of the present disclosure provide a wireless communication method, a terminal device, and a network device. The terminal device can report an occurrence of RLF in a source cell in a DAPS handover process, such that the network device can optimize a threshold corresponding to a measurement event in a measurement configuration, thereby ensuring the effectiveness of the subsequent DAPS handover configuration and optimizing the DAPS handover. The wireless communication method includes: transmitting, by a terminal device, first indication information to a network device. The first indication information indicates that an RLF occurs between the terminal device and a source cell in a handover process of the terminal device from the source cell to a target cell using a DAPS handover scheme. The network device is a network device of the target cell, a network device of a cell for reestablishment after the DAPS handover fails, or a network device of the source cell.