Conditional Handover Data Forwarding With Target Node Feedback
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Solution Overview
Problem
In conditional handover scenarios, the source cell lacks knowledge about which target cell the UE has attached to, leading to inefficiencies in data forwarding, as multiple potential target cells are prepared, resulting in potential resource wastage and signaling overhead.
Innovation Solution
Implement data forwarding techniques that include the final target node notifying the source, the source performing forwarding to potential nodes, the UE informing the source about the target, or a hybrid approach involving both the UE and the final target node signaling the source, to ensure efficient data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data forwarding is performed to multiple potential target cells, then the UE can successfully attach to a target cell, but resource wastage and signaling overhead increase
Solution Approach 1:
The source cell performs data forwarding to multiple potential target cells in advance before the UE actually attaches to any target cell. This preliminary action ensures that data is already available at the target cell when the UE attaches, preventing data loss and ensuring seamless handover without waiting for the UE to select a target cell first
Solution Approach 2:
The source cell acts as an intermediary by temporarily holding and forwarding data to multiple potential target cells. This intermediary role allows the network to prepare data forwarding paths in advance while the UE performs measurements and selects the best target cell, resolving the timing conflict between data forwarding and UE attachment
2Reliability
If data forwarding is performed to multiple potential target cells, then the UE can successfully attach to a target cell, but signaling overhead increases
Solution Approach 1:
The network performs data forwarding setup in advance by configuring the source cell to forward data to multiple potential target cells before handover execution. This preliminary configuration reduces signaling overhead during the actual handover process, as the forwarding paths are already established and do not require additional signaling when the UE attaches
Solution Approach 2:
The system implements feedback mechanisms where the source cell receives notifications from target cells about UE attachment status. This feedback allows the source cell to stop forwarding data to target cells that are not selected, optimizing resource usage and reducing unnecessary signaling overhead while maintaining reliable handover
3Adaptability or versatility
If the source cell does not know which target cell the UE has attached to, then multiple target cells can be prepared, but data forwarding efficiency decreases
Solution Approach 1:
The source cell is configured to forward data to multiple potential target cells in advance without knowing which one the UE will attach to. This preliminary data preparation ensures that regardless of which target cell the UE selects, the data is already available, maintaining high data forwarding efficiency while preserving adaptability to different handover scenarios
Solution Approach 2:
The source cell acts as an intermediary data forwarding node that distributes data to multiple potential target cells simultaneously. This intermediary approach allows the system to maintain both adaptability (preparing multiple targets) and efficiency (data already available at all potential targets) by decoupling the data forwarding decision from the UE attachment decision
Data Source
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AI summary
Techniques to configure a source base station (SBS) for conditional handover and data forwarding between the SBS and a target base station (TBS) are discussed. A measurement report received from a UE is decoded, the measurement report triggered based on a first threshold associated with a configured measurement event. RRC signaling is encoded for transmission to the UE, the RRC signaling including a conditional handover command for handover from the SBS to the TBS. The conditional handover command indicates a second threshold for the measurement event, the second threshold being higher than the first threshold. At least one notification message from the TBS and/or the UE is decoded, where the at least one notification message indicates successful completion of the handover and attachment of the UE to the TBS. UE uplink data and UE downlink data are encoded for forwarding to the TBS, based on the notification message.