IAB Backhaul Path Switching for Link Degradation and Failure

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Solution Overview

Problem

The introduction of micro-cellular networks with IAB nodes in 5G systems leads to radio link failures due to obstructions and interference, causing loss of connectivity, and the need for flexible and cost-effective solutions to manage link degradation and failures in integrated access and backhaul networks.

Innovation Solution

Implement methods and network nodes that detect link degradation, broadcast messages for path setup, buffer uplink data, and reconfigure paths to maintain connectivity by utilizing neighbor nodes and multiple communication paths, including attaching to target network nodes and establishing control paths based on channel quality and capacity measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If IAB nodes are deployed to create micro-cellular networks, then network coverage and capacity are improved, but radio link failures occur due to obstructions and interference

Engineering Contradiction:

Improvenetwork coverageVSAvoidradio link stability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The network node proactively detects link degradation before complete failure occurs and pre-establishes a new backhaul path through neighbor nodes. This preliminary action allows the system to switch paths before connectivity is lost, maintaining network reliability while preserving the extended coverage benefits of micro-cellular deployment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically reconfigures backhaul paths by selecting different neighbor nodes based on real-time link quality measurements. When obstructions or interference affect a current path, the system adapts by routing traffic through alternative nodes, thereby maintaining reliable connectivity across the extended network coverage area

Inventive Principle:

Principle #15Dynamics

2Reliability

If cable laying is used to connect micro-base stations, then connection stability is improved, but deployment flexibility and cost increase

Engineering Contradiction:

Improveconnection stabilityVSAvoiddeployment flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical cable-based connection system with a wireless backhaul system using IAB nodes. The wireless system achieves connection stability through dynamic path selection and redundancy mechanisms while restoring deployment flexibility by eliminating the need for physical cable installation to each micro-base station

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If wireless backhaul is used in IAB networks, then deployment flexibility is improved, but link degradation and failures occur due to obstructions and interference

Engineering Contradiction:

Improvedeployment flexibilityVSAvoidlink stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system introduces neighbor nodes as intermediary elements that provide alternative transmission paths. When the direct wireless link between IAB nodes degrades due to obstructions or interference, traffic is routed through intermediate neighbor nodes, maintaining link stability while preserving the deployment flexibility of wireless backhaul

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes operational parameters by dynamically selecting different backhaul paths based on link quality measurements. When link degradation is detected, the system switches to alternative paths with better quality parameters, thereby maintaining reliability while keeping the wireless deployment flexible

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12538204B2Methods, apparatuses, architectures and systems for handling link degradation and/or link failure in an integrated access and backhaul (IAB) network

Publication Date: 2026.01.27 INTERDIGITAL PATENT HOLDINGS INC

AI summary

An Integrated Access and Backhaul, IAB, node determines link degradation in a primary path to a first Distributed Unit, DU, of a gNB, establishes a secondary path with a second DU of a gNB, detects link failure in the primary path, releases the primary path and makes the second primary path as a new primary path. A first IAB donor node receives an indication of link degradation from an IAB node in a network managed by the first IAB donor node, determines that an available IAB node is in a network managed by a second IAB donor node, sends to the second IAB donor node a request to connect the IAB node with the second IAB donor node and, in case the request is accepted, requests the IAB node to connect with the second IAB donor node. An IAB can also measure channel quality for a first path to a first IAB donor node and for a second path to a second IAB donor node and, in case the channel quality of both the first path and the second path is below a threshold, duplicate traffic on both the first path and the second path, in case the channel quality of the first path is below the threshold and the channel quality of the second channel is above the threshold, send traffic only over the second path and, in case the channel quality of the first path is above the threshold, send traffic only over the first path.