IAB Donor-CU Migration for Seamless Distributed Unit Handover
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Solution Overview
Problem
Existing technologies lack a method for efficiently migrating a distributed unit (DU) in an integrated access and backhaul (IAB) node, particularly in scenarios involving mobile relays, which affects packet data convergence protocols and radio resource control connections.
Innovation Solution
A method and apparatus for migrating an F1-terminating donor of an IAB-node from a first donor central unit (donor-CU) to a third donor-CU, involving a radio resource control (RRC) terminating donor, with specific processing units controlling the migration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IAB-node uses traditional single-donor architecture, then network structure is simple, but mobility support and connectivity flexibility are limited
Solution Approach 1:
The patent segments the donor-CU function into multiple independent donor-CUs, allowing an IAB-node to connect to different donor-CUs for different purposes (F1-terminating donor for user plane, RRC-terminating donor for control plane). This segmentation enables flexible mobility support while maintaining manageable architecture through functional separation.
Solution Approach 2:
The patent implements multi-functionality by allowing a single IAB-node to simultaneously connect to multiple donor-CUs with different roles (F1-terminating and RRC-terminating). This universal connection capability enables the node to support both traditional single-donor operations and advanced mobility scenarios, enhancing adaptability without requiring separate dedicated architectures.
2Adaptability or versatility
If IAB-node migrates F1-terminating donor from first donor-CU to third donor-CU, then connectivity flexibility improves, but migration complexity and disruption risk increase
Solution Approach 1:
The patent introduces a second donor-CU as an intermediary during the migration process. The F1-terminating donor migrates from the first donor-CU to the third donor-CU while the second donor-CU (which may be identical to either first or third) acts as a mediator to coordinate the migration, ensuring seamless transition and reducing disruption to ongoing communications.
Solution Approach 2:
The patent implements preliminary actions by establishing the relationship between the second donor-CU and either the first or third donor-CU before initiating the migration. This pre-configuration of the intermediary connection enables the migration process to proceed smoothly without requiring complex real-time coordination, thereby reducing migration complexity.
3Reliability
If IAB-node maintains connections to multiple donor-CUs, then service continuity improves, but resource management complexity increases
Solution Approach 1:
The patent segments the resource management function by separating F1-terminating donor connections from RRC-terminating donor connections. Each segment can be managed independently, allowing the network to maintain multiple connections for different services (user plane mobility, control plane connectivity) without creating a single complex management system.
Solution Approach 2:
The patent applies local quality by allowing different donor-CUs to serve different local needs of the IAB-node. The F1-terminating donor-CU provides user plane connectivity optimized for data traffic, while the RRC-terminating donor-CU provides control plane connectivity optimized for signaling, enabling each connection to be optimized for its specific function rather than managing all resources uniformly.
Data Source
AI summary
An apparatus for controlling migration of a distributed unit, applicable to an integrated access and backhaul node (IAB-node), includes: first processor circuitry controlling the node to execute the following: migrating an F1 terminating donor of the node from a first donor central unit (donor-CU) to a third donor-CU, wherein a radio resource control (RRC) terminating donor of the node is a second donor-CU, the second donor-CU being identical to the first donor-CU, or the second donor-CU being identical to the third donor-CU, or the second donor-CU being different from both the first donor-CU and the third donor-CU, and the node has two logical IAB-DUs, wherein the first IAB-DU has F1 connection with a first donor-CU and a second IAB-DU has F1 connection with the third donor-CU.