Dual-Connectivity PDCP Anchor Transfer for Shorter Handover Interruptions
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Solution Overview
Problem
Existing wireless communication systems face challenges in managing mobility, particularly during handovers, leading to interruptions and suboptimal user experience, especially in high-speed scenarios like high-speed trains and aerial use cases.
Innovation Solution
A method involving a central unit (CU) in a first radio access network node establishes dual connectivity with a second RAN node, performs a packet data convergence protocol (PDCP) anchor change, and instructs the first RAN node not to release its distributed unit (DU) during handovers, ensuring simultaneous connectivity with source and target cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional handover procedure is used, then network structure is simple, but handover interruption time increases and user experience deteriorates
Solution Approach 1:
The patent applies preliminary action by establishing dual connectivity between source and target RAN nodes before the actual handover occurs. The target RAN node is prepared in advance with all necessary configuration, and the UE is pre-configured with measurement settings to identify suitable target nodes before handover is needed, thereby reducing handover interruption time.
Solution Approach 2:
The patent segments the handover process into distinct phases: dual connectivity establishment phase, handover decision phase, and execution phase. By segmenting the network functions into source RAN node, target RAN node, and core network entities, the system can manage complexity through modular architecture while reducing handover disruption.
2Reliability
If dual connectivity is established for handover preparation, then handover interruption time is reduced, but network resource consumption increases
Solution Approach 1:
The system performs preliminary actions by pre-establishing dual connectivity and configuring measurement settings before handover is needed. This ensures that when handover occurs, the target node is already ready, improving reliability while the temporary resource allocation is minimized through efficient resource management.
Solution Approach 2:
The patent implements dynamic resource management where network resources are allocated dynamically based on UE mobility conditions. Dual connectivity is established only when necessary, and resources are released after handover completion, optimizing the balance between reliability and resource consumption.
3Stability of the object's composition
If PDCP anchor change is performed during handover, then connectivity is maintained, but data transmission interruption may occur
Solution Approach 1:
The patent applies preliminary action by pre-establishing dual connectivity and configuring the target RAN node before handover. The PDCP anchor is changed in advance during dual connectivity setup, so that when handover executes, the data path is already prepared, maintaining connectivity stability while minimizing data transmission interruption.
Data Source
AI summary
A method performed by a central unit (CU) in a first radio access network (RAN) node comprises: establishing a dual connectivity (DC) of the first RAN node and a second RAN node for a wireless device; providing a service to the wireless device in the DC based on a distributed unit (DU) of the first and second RAN nodes; receiving, from a CU of the second RAN node in the DC, handover information for a handover of the wireless device from the second RAN node to the first RAN node; performing a packet data convergence protocol (PDCP) anchor change from the CU of the second RAN node to the CU of the first RAN node based on the handover information; and transmitting, to the DU of the first RAN node, a message comprising information instructing not to release the DU of the first RAN node after the PDCP anchor change.