IAB-Node Migration Configuration Update via SIB and RRC Forwarding

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Solution Overview

Problem

Current systems face challenges in efficiently updating configuration information for IAB nodes during inter-donor migration in 5G NR wireless communication, particularly regarding IAB-node configuration during handovers between different IAB-donors.

Innovation Solution

The method involves updating configuration information for downstream devices of a migrating IAB-node during inter-donor migration by providing updated information in system information blocks other than SIB1, encoding it, and sending it via RRC containers or dedicated RRC messages through F1-AP, ensuring seamless handovers and efficient network performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If configuration information is updated during inter-donor migration, then migration reliability is improved, but system complexity increases

Engineering Contradiction:
Improvemigration reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The source IAB-donor CU proactively provides updated configuration information to the migrating IAB-node DU before the actual migration is complete. This preliminary action ensures that the downstream device receives correct configuration data (including new NR PCI) in advance, preventing configuration errors during migration and improving overall migration reliability without requiring complex real-time coordination mechanisms

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary message transfer mechanism where the source IAB-donor CU sends configuration information through the migrating IAB-node DU via F1-AP interface. This intermediary approach allows configuration updates to be propagated reliably through the migration path without requiring direct communication between source and target donors, simplifying the overall system architecture while ensuring accurate configuration delivery

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If configuration information is provided through system information blocks, then configuration accuracy is improved, but information transmission overhead increases

Engineering Contradiction:
Improveconfiguration accuracyVSAvoidinformation transmission overhead
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The configuration information is segmented and embedded within existing system information blocks (SIBs) rather than transmitting as a separate dedicated message. By integrating the configuration data into standard SIB structures that are already part of the system information broadcast, the patent achieves accurate configuration delivery while avoiding additional overhead from separate transmission channels

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes existing system information blocks for multiple purposes: their original function of broadcasting system parameters and the additional function of conveying migration-specific configuration information. This multi-functionality approach allows the same information structure to serve dual purposes, improving configuration accuracy without increasing overall information transmission overhead

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

3Reliability

If dedicated RRC messages are used for configuration update, then configuration delivery reliability is improved, but signaling overhead increases

Engineering Contradiction:
Improveconfiguration delivery reliabilityVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent merges the configuration update function with existing dedicated RRC message structures used for other purposes during migration. By combining multiple functions (migration management and configuration delivery) into a single message exchange, the patent ensures reliable configuration delivery through the established RRC signaling path while minimizing additional overhead from separate dedicated configuration messages

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4104418B1Updating configuration information of downstream devices during inter-donor migration
Publication Date: 2025.11.26 ZTE CORP
  • EP4104418B1 patent drawingFigure 1A
  • EP4104418B1 patent drawingFigure 1B
  • EP4104418B1 patent drawingFigure 2

AI summary

The present disclosure describes methods, systems, and devices for updating configuration information for a downstream device of a migrating integrated access backhaul node (IAB-node) during an inter-donor migration from a source IAB-donor to a target IAB-donor. The method includes providing, by an IAB-donor central unit (CU), updated configuration information into system information which is contained in a system information block (SIB) other than SIB1 carried in a SystemInformation (SI) message, and encoding the system information with the updated configuration information. The method also include sending, by the IAB-donor CU, the system information including the updated configuration information as a radio resource control (RRC) container to a migrating IAB-node distributed unit (DU) via F1-AP. The method further includes the migrating IAB-node DU forwards the system information including the updated configuration information through a dedicated RRC message to the downstream device.