IAB Node Inter-Donor Migration Handover
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Solution Overview
Problem
Current integrated access and backhaul (IAB) mobility management procedures face challenges in inter-donor migration, particularly in maintaining session continuity and managing context changes during topology adaptations, which can lead to signaling overload and potential packet loss due to incorrect security key application.
Innovation Solution
A method for inter-donor migration of IAB nodes involves transmitting handover requests and configurations between source and target donors, with processing hardware managing IAB-node configurations and downlink data forwarding to ensure seamless communication and correct security key management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures with messaging between RAN nodes are used, then mobility management is achieved, but latency increases and handover failure probability increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring conditional handover parameters and security context information at the source donor before the actual handover occurs. The target donor is pre-prepared with necessary context, and the UE is provided with conditional execution parameters that include alternative security keys. This advance preparation eliminates the need for extensive messaging during the handover execution phase, thereby reducing latency while maintaining reliability.
2Reliability
If security key changes are managed during IAB-node migration, then service continuity is maintained, but signaling overhead increases
Solution Approach 1:
The patent merges the security key management process with the existing handover signaling流程. Instead of implementing separate key update procedures that would generate additional signaling, the security context information including alternative keys is integrated into the handover request and handover command messages. This combining approach maintains service continuity through proper key management while avoiding the signaling overhead that would result from separate key update procedures.
3Adaptability or versatility
If IAB-node configuration is updated during migration, then topology adaptation is achieved, but packet loss risk increases due to incorrect security key application
Solution Approach 1:
The patent introduces an intermediary mechanism in the form of a UE-side security context manager that acts as a mediator between the network configuration updates and the actual data transmission. The UE maintains multiple security contexts and selectively applies the appropriate key based on the current serving donor, rather than relying solely on network-side key management. This intermediary layer at the UE ensures that even during topology adaptation with configuration updates, the correct security key is applied, preventing packet loss due to key mismatches.
Data Source
AI summary
A source donor supports inter-donor migration of an integrated access backhaul (IAB) node from the source donor to a target donor, where the source donor and the target donor corresponding to respective nodes of a radio access network (RAN), and when a user equipment (UE) is in communication with the RAN via the IAB-node. The source donor transmits, to the target donor, a handover request message related to the IAB-node; receives, from the target donor, a handover request acknowledge message including an IAB-node configuration related to the inter-donor migration of the IAB-node; provides the IAB-node configuration to the IAB-node; and transmits downlink data for the UE to the target donor, for forwarding to the UE via the IAB-node.