IAB-Node F1 Interface Handover via Transport Network Layer Connectivity
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Solution Overview
Problem
Current 5G wireless communication systems face challenges in maintaining communication and signaling interfaces during network role transitions, particularly in mobile deployment scenarios like buses or trains, where handovers between source and target IAB-Donor base stations are complex and lack defined protocols for integrated access and backhaul node handovers.
Innovation Solution
The implementation of F1 interface application protocol procedures between the Distributed Unit of an IAB-Node and the Central Unit of a Source IAB-Donor to establish an F1 interface with a Target IAB-Donor, enabling handover of the IAB-Node by sending measurement result information to trigger the handover, creating Transport Network Layer connectivity, exchanging application layer configuration data, and setting up a second F1 interface with the Target Central Unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mobile IAB-Node base station handover between IAB-Donors is implemented, then mobility and adaptability are improved, but communication interface stability and signaling reliability deteriorate due to lack of defined protocols
Solution Approach 1:
The patent applies preliminary action by establishing the F1 interface configuration and Transport Network Layer connectivity before the handover is executed. The source IAB-Donor prepares the target IAB-Donor with necessary configuration information, and the F1 interface is set up in advance, ensuring that communication stability is maintained during the mobility transition without protocol gaps.
2Reliability
If F1 interface procedures are established between Distributed Unit and Central Unit for handover, then signaling reliability is improved, but device complexity increases due to additional interface management
Solution Approach 1:
The patent applies universality by making the F1 interface procedures multi-functional: the same F1 interface established between the Distributed Unit and Central Unit serves both normal operation and handover functions. This eliminates the need for separate handover-specific interfaces, reducing overall system complexity while maintaining signaling reliability during handover.
Solution Approach 2:
The source IAB-Donor acts as an intermediary that facilitates the F1 interface establishment between the target IAB-Donor and the Distributed Unit. By managing the configuration and connectivity through the source IAB-Donor, the complexity of direct peer-to-peer interface management is reduced, and signaling reliability is improved through coordinated handover procedures.
3Productivity
If Transport Network Layer connectivity is created and application layer configuration data is exchanged, then data rate and throughput are improved, but loss of time increases during configuration exchange
Solution Approach 1:
The patent applies preliminary action by pre-configuring the Transport Network Layer connectivity and application layer configuration data during the handover preparation phase, before the actual handover execution. This allows the Distributed Unit to have configuration information ready, reducing the time required during the actual handover event while ensuring high data rates are achieved immediately upon handover completion.
Data Source
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AI summary
This document describes methods, devices, systems, procedures, and means of maintaining communication and signaling interfaces during network role transitions, such as a secondary node change or a handover. A source secondary base station holds a source donor Central Unit (Source CU) (810) for its own Distributed Unit (source DU) (822) and for the Distributed Unit(s) of the node base station(s) (node DU) (836). The source secondary base station (123) connects to the node base station (832) via a first F1 interface. The node DU (836) triggers handover of the node base station (832) and connected User Equipment (UE) (110) from the source secondary base station (123) to a target secondary base station (125). The node base station (832) creates Transport Network Layer (TNL) connectivity toward a target donor Central Unit (Target CU) (860) and exchanges application layer configuration data with the Target CU (860) via a wireless backhaul link implemented utilizing the TNL connectivity. The node base station (832) then sets up a second F1 interface with the Target CU (860) and handover of the node base station (832) and connected User Equipment (UE) (110) from the source secondary base station (123) to a target secondary base station (125) is performed.