CU-DU Communication Coordination for Dual-Connectivity Negotiation
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Solution Overview
Problem
In dual connectivity (DC) communication systems, there is no solution for inter-node negotiation between a master node (MN) and a secondary node (SN) when the MN uses a CU-DU architecture, which is necessary to prevent joint configurations from exceeding the terminal device's capabilities.
Innovation Solution
A communication method where a DU determines and provides lower layer configuration information to assist the SN in negotiating with the MN, using request and response messages to facilitate inter-node negotiation, including information such as DRX cycles, power headroom, and band combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the MN uses a CU-DU architecture to reduce deployment costs, then deployment cost is reduced, but inter-node negotiation between MN and SN cannot be completed
Solution Approach 1:
The MN is segmented into CU and DU parts, where the CU handles RRC message generation and the DU handles lower layer configuration. This segmentation allows the CU-DU architecture to be implemented while maintaining negotiation capability through clear functional division and message passing between CU and DU.
Solution Approach 2:
The CU acts as an intermediary between the DU and the SN. The CU receives negotiation requests from the SN, formulates appropriate RRC messages by incorporating DU's configuration capabilities, and sends them to the SN, thereby enabling negotiation completion despite the architectural split.
2Reliability
If the MN and SN perform inter-node negotiation to prevent capability exceedance, then terminal device capability compliance is ensured, but the complexity of the negotiation process increases
Solution Approach 1:
The CU is designed to handle multiple functions: it manages both the RRC protocol stack and the inter-node negotiation process, and it coordinates with the DU for configuration generation. This multi-functionality reduces the need for separate dedicated components, thereby managing complexity while ensuring capability compliance.
Solution Approach 2:
The DU pre-determines its configuration capabilities and provides them to the CU before actual negotiation with the SN. This preliminary preparation allows the CU to efficiently construct negotiation messages without real-time complex calculations, reducing negotiation process complexity while ensuring capability compliance.
3Ease of operation
If the CU handles RRC functions to manage configuration, then configuration management is improved, but the DU cannot directly participate in inter-node negotiation
Solution Approach 1:
The CU merges the RRC configuration management function with the inter-node negotiation function. By integrating these functions in the CU and establishing a formal interface with the DU, the system ensures that lower layer configuration information from the DU is properly incorporated into RRC messages during negotiation, preventing information loss while maintaining ease of operation.
Solution Approach 2:
The CU requests lower layer configuration information from the DU through a defined interface during the negotiation process. This feedback mechanism ensures that the CU has access to necessary DU capabilities when constructing negotiation messages, preventing information loss while maintaining centralized configuration management.
Data Source
Figure 1(a)~1(d)
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AI summary
Embodiments of this application provide a communication method and apparatus, and relate to the communication field, so that an inter-node negotiation process between an MN and an SN can be completed when the MN uses a CU-DU architecture in DC communication. The method includes: A DU receives a first request message from a CU, where the first request message is used to request the DU to determine configuration information of an MN, and the configuration information of the MN is used to assist an SN in determining configuration information used for a terminal device; and the DU sends a first response message to the CU, where the first response message includes the configuration information of the MN. Embodiments of this application are applied to a DC scenario.