Dual-Path Radio Link Failure Handling During Cell Path Switch

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Solution Overview

Problem

Radio link failures during path switches in telecommunication networks cause connectivity interruptions, increased power consumption, and signaling overhead, particularly when a terminal device switches between cells.

Innovation Solution

A method and apparatus that allow a terminal device to maintain multiple paths during a switch, detecting and reporting radio link failures on one path while continuing the switch on another path, thereby avoiding direct RRC reestablishment and reducing connectivity interruptions and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal device triggers RRC reestablishment procedure upon detecting radio link failure during path switch, then the radio link failure can be handled, but connectivity interruption time increases and power consumption increases

Engineering Contradiction:

Improveradio link failure handlingVSAvoidconnectivity interruption time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the terminal device detect and report radio link failure status to the network entity before completing the path switch procedure. The network entity receives the RLF indication and can prepare alternative paths or maintain existing paths, avoiding the need for complete path abandonment and reestablishment, thereby reducing connectivity interruption time while still ensuring reliable failure handling

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces the network entity as an intermediary that coordinates between the terminal device and the path switch procedure. The network entity receives RLF indications from the terminal device and manages the path switch process, allowing for more coordinated and efficient failure handling that reduces overall connectivity interruption time compared to terminal-initiated reestablishment procedures

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the terminal device triggers RRC reestablishment procedure upon detecting radio link failure during path switch, then the radio link failure can be handled, but signaling overhead increases

Engineering Contradiction:

Improveradio link failure handlingVSAvoidsignaling overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential failure indication information from the complete RRC reestablishment procedure. Instead of triggering a full reestablishment sequence with multiple signaling messages, the terminal device only needs to send a concise RLF indication to the network entity. This extraction of critical failure information reduces signaling overhead while maintaining reliable failure handling capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by having the network entity initiate or coordinate the path switch procedure based on terminal indications, rather than having the terminal device independently manage the entire reestablishment process. This inversion shifts the signaling burden to the network side, reducing terminal-side signaling overhead while ensuring reliable failure handling

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of time

If the terminal device maintains multiple paths during path switch, then connectivity interruptions are reduced, but device complexity increases

Engineering Contradiction:

Improveconnectivity interruptionVSAvoidpath management complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies universality by having the terminal device maintain multiple paths (first path and second path) simultaneously during the path switch procedure. The terminal device can use either path for communication depending on availability, providing multi-functionality that reduces connectivity interruptions. The network entity also maintains awareness of multiple paths to coordinate failures effectively

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback mechanisms where the terminal device reports radio link failure status on each path to the network entity. This feedback allows the network entity to monitor the status of multiple paths and make informed decisions about path selection and switch coordination, managing the complexity of multi-path operation through centralized control and information sharing

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250386256A1Method and apparatus for handling radio link failure during path switch

Publication Date: 2025.12.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Embodiments of the present disclosure provide a method and an apparatus for handling radio link failure during path switch. A method performed by a terminal device comprises: receiving a command, indicating a switch for the terminal device between a first cell and a second cell, and indicating the terminal device to keep a first path with the first cell and a second path with the second cell during the switch; detecting a first radio link failure, RLF, on the first path, and/or a second RLF on the second path; and transmitting a first message indicating a first RLF over the second path, when the first RLF is detected on the first path. Accordingly, the terminal device does not abort current radio links/paths directly, and connectivity interruption may be avoided.