IAB Backhaul Link Failure Handling for Descendant Reestablishment

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Solution Overview

Problem

In Integrated Access Backhaul (IAB) networks, existing technologies fail to prevent reestablishment at descendant nodes when there are no alternative paths available, leading to potential deadlocks and inefficiencies in network recovery.

Innovation Solution

Implementing a method where descendant nodes respond to a Type 2 BH RLF indication by providing information about hosted cells and alternative path availability to their parent nodes, preventing unnecessary reestablishment attempts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If descendant nodes attempt reestablishment when backhaul link fails, then network recovery is attempted, but deadlocks occur when no alternative paths exist

Engineering Contradiction:

Improvenetwork recoveryVSAvoiddeadlocks

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The parent node performs preliminary assessment by requesting alternative path information from descendant nodes before allowing reestablishment attempts. This preliminary action prevents deadlocks by ensuring reestablishment only occurs when viable alternative paths exist, eliminating the harmful effect while preserving network recovery capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanism where descendant nodes report their alternative path availability to parent nodes. This feedback loop enables the parent node to make informed decisions about permitting reestablishment, resolving the contradiction by using information flow to prevent deadlocks while maintaining reliable network recovery

Inventive Principle:

Principle #23Feedback

2Productivity

If reestablishment is permitted at all descendant nodes, then network recovery coverage is maximized, but unnecessary reestablishment attempts occur at nodes without alternative paths

Engineering Contradiction:

Improvenetwork recovery coverageVSAvoidunnecessary reestablishment attempts

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Before permitting reestablishment, the parent node performs preliminary verification by checking alternative path availability information from descendant nodes. This preliminary action filters out nodes without viable paths, preventing wasteful reestablishment attempts while maintaining comprehensive recovery coverage at eligible nodes

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies different reestablishment permissions to different descendant nodes based on their individual alternative path availability. Nodes with alternative paths are permitted to reestablish while those without are blocked, creating localized quality differentiation that eliminates unnecessary attempts while preserving productive recovery elsewhere

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12501504B2Preventing reestablishment at descendant nodes with no alternative paths in integrated access backhaul

Publication Date: 2025.12.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method, system and apparatus are disclosed for preventing reestablishment at descendant nodes with no alternative paths in Integrated Access Backhaul (IAB) networks. In one embodiment, a method implemented in a network node configured to communicate with at least one descendant node over a backhaul network includes transmitting an indication to the at least one descendant network node in which the indication is associated with a radio link failure; and receiving at least one message in response to the indication, the at least one message being associated with an alternative path availability of the at least one descendant network node toward a third network node.