CU-DU Mobility Management for 5G Handover Optimization
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Solution Overview
Problem
The current 5G system lacks an effective mobility management solution for handover operations, resulting in increased handover delays due to the need for complex reconfiguration of radio link control and packet data convergence protocol layers in the CU-DU architecture.
Innovation Solution
A mobility management method is introduced that involves a centralized unit selecting a target cell based on measurement reports from terminal devices, sending configuration information, and performing air interface resource reconfiguration, while optionally indicating whether re-establishment of RLC and PDCP layers is necessary, thereby optimizing handover processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device performs complete reconfiguration of RLC and PDCP layers during handover in the CU-DU architecture, then the handover reliability is improved, but the handover delay increases
Solution Approach 1:
The patent applies partial action by selectively reconfiguring only necessary protocol layers during handover. The CU determines whether RLC and PDCP layer reconfiguration is actually needed based on specific conditions, rather than performing complete reconfiguration unconditionally. This partial approach reduces handover delay while maintaining reliability when reconfiguration is truly necessary.
Solution Approach 2:
The patent changes the parameter of reconfiguration necessity by introducing condition-based determination. The CU evaluates specific parameters and conditions to decide whether RLC and PDCP layer reconfiguration should be performed, transforming the fixed reconfiguration process into a dynamic, condition-dependent process that optimizes both reliability and delay.
2Productivity
If the CU performs air interface resource reconfiguration for target cell, then the handover efficiency is improved, but the system complexity increases
Solution Approach 1:
The patent segments the handover control functions by separating the CU's role in determining reconfiguration necessity from the actual reconfiguration execution. The CU focuses on high-level decision-making about whether reconfiguration is needed, while the target cell handles the specific reconfiguration actions. This segmentation improves efficiency by clear division of responsibilities while managing complexity through functional separation.
Solution Approach 2:
The CU acts as an intermediary that coordinates between the source cell and target cell during handover. It determines whether reconfiguration is necessary and communicates this decision to the target cell, which then executes the appropriate actions. This intermediary role streamlines the handover process and improves efficiency while keeping the system architecture manageable.
Data Source
AI summary
According to the present disclosure, a mobility management method, an access network device, and a terminal device are disclosed. A base station system includes a centralized unit and a distributed unit, the centralized unit communicates with the distributed unit, and the distributed unit communicates with a terminal device through an air interface. An example method includes: selecting, by the centralized unit, a target cell as a secondary cell based on a measurement report reported by the terminal device, and sending configuration information of the target cell to the terminal device through the distributed unit; and receiving, by the centralized unit, primary cell change indication information sent by the distributed unit, performing air interface resource reconfiguration for the target cell based on the primary cell change indication information, generating reconfiguration information, and sending, by the centralized unit, the reconfiguration information to the terminal device through the distributed unit.