IAB Node Inter-CU Recovery for Backhaul Link Failure Handover
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Solution Overview
Problem
Existing wireless communication systems face challenges in improving mobility robustness for integrated access backhaul (IAB) nodes, particularly in scenarios where a radio link failure (RLF) is detected, affecting the efficient recovery of IAB nodes to new parent nodes.
Innovation Solution
The proposed solution involves methods for inter-CU recovery of IAB nodes, including context information retrieval, connection configuration, and F1 procedure management between IAB-donor-CUs and IAB-nodes, along with UE context handling and descendant device management to ensure seamless handover and efficient transmission during RLF recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IAB-node recovery procedures are implemented in existing wireless communication systems, then mobility robustness is improved, but system complexity increases due to additional context retrieval and inter-CU coordination requirements
Solution Approach 1:
The patent applies preliminary action by pre-establishing context information storage mechanisms in IAB-donor-CUs before recovery is needed. When an IAB-node experiences radio link failure, the context is already available at the donor-CU level, enabling rapid recovery without complex real-time coordination. The F1 interface is pre-configured to support context retrieval operations, allowing the system to quickly switch donors without establishing new connection protocols during the recovery process.
2Productivity
If context information retrieval between IAB-donor-CUs is implemented, then IAB-node recovery efficiency is improved, but transmission overhead increases
Solution Approach 1:
The patent extracts only the essential context information needed for recovery (such as UE context, bearer information, and security parameters) from the source IAB-donor-CU and transfers it to the target IAB-donor-CU. This selective extraction avoids transmitting unnecessary data, reducing transmission overhead while ensuring the target donor has sufficient information to resume service for the recovering IAB-node.
3Reliability
If F1 procedure management is implemented for inter-CU recovery, then connection reliability is improved, but procedure complexity increases
Solution Approach 1:
The patent implements a universal F1 procedure framework that handles multiple functions (context retrieval, connection establishment, configuration transfer) through a standardized message exchange mechanism. The same F1 interface and message structures are used whether for initial setup, handover, or recovery scenarios, reducing the need for separate complex procedures for each function while maintaining reliable connections.
Data Source
AI summary
The present disclosure describes methods, systems, and devices for releasing resources for a recovery integrated access backhaul-node (IAB-node) and/or avoiding, from performing radio resource control (RRC) reestablishment procedure, at least one descendant device of a recovery integrated access backhaul-node (IAB-node) from an initial IAB-donor-central unit (CU) to a new IAB-donor-CU. One method includes sending, by the new IAB-donor-CU to the initial IAB-donor-CU, a user equipment (UE) context release information to indicate the resources to be released; and upon receiving the UE context release information, releasing, by the initial IAB-donor-CU, the resources indicated by the UE context release information. Another method includes sending, by the new IAB-donor-CU to the initial IAB-donor-CU, a message. Another method includes sending, by the initial IAB-donor-CU to the at least one descendant device via the new IAB-donor-CU or new IAB-donor-DU, a radio resource control (RRC) message.