Dual Connectivity Setup Across Split CU Control and User Planes
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Solution Overview
Problem
The current dual-connectivity (DC) method defined for Central Unit (CU) and Distributed Unit (DU) architectures is not applicable to new architectures where the CU is further divided into Control Plane (CP) and User Plane (UP) functional entities.
Innovation Solution
A method and device for establishing dual-connectivity (DC) in architectures where the CU is divided into CP and UP, involving specific message exchanges between the Control Plane functional entity (CP) and User Plane functional entity (UP) of the Secondary Node (SN) and Distributed Unit (DU) to facilitate DC establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the CU is divided into CP and UP functional entities, then network flexibility and adaptability are improved, but the complexity of DC establishment procedures increases
Solution Approach 1:
The CU is segmented into CP and UP functional entities with distinct roles. The CP handles control plane functions including DC establishment signaling, while the UP handles user plane data transmission. This segmentation allows the system to support flexible network architectures while managing complexity through functional separation.
Solution Approach 2:
The CP acts as an intermediary between the MN and the UP entities. It receives DC establishment requests from the MN, processes the control plane signaling, and coordinates with the UP to establish the data bearers. This intermediary role simplifies the overall establishment procedure by providing a clear interface between control and user plane functions.
2Adaptability or versatility
If new message exchange procedures are implemented for DC establishment, then compatibility with new architectures is improved, but the signaling overhead increases
Solution Approach 1:
The message exchange procedures are designed to be universal and applicable to multiple network architectures. The same signaling mechanisms can accommodate both traditional CU-DU architectures and the new CP-UP divided architectures, reducing the need for architecture-specific signaling variants and thereby controlling signaling overhead.
3Reliability
If multiple message exchanges are performed between CP, UP, and DU, then DC establishment reliability is improved, but the establishment time increases
Solution Approach 1:
The CP performs preliminary control plane configuration and coordination with the UP before finalizing the DC establishment with the DU. By preparing the control plane settings and UP resource allocations in advance, the system ensures reliable DC establishment while minimizing the actual establishment time when the DU joins the connection.
Data Source
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AI summary
Embodiments of the present invention provide a dual-connectivity (DC) establishment method and device. A method, performed by a central unit, CU, entity of a secondary node in a wireless communication system for establishing a dual connectivity, DC, comprises: receiving (301, 801), by a control plane functional entity, CP, of the CU from a master node, a secondary node setup request message; transmitting (302, 802), by the CP to a user plane functional entity, UP of the CU, a resource setup request message based on the secondary node setup request message; and receiving (303, 803), by the CP from the UP, a resource setup response message as a response to the resource setup request message; wherein the resource setup request message includes duplication activation information on state of downlink, DL, packet data convergence protocol, PDCP, duplication.