CU-DU Layer 2 Coordination for Bearer Conversion
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Solution Overview
Problem
Current communication technologies, particularly in the 5G network, lack explicit solutions for how the Central Unit (CU) and Distributed Unit (DU) cooperate to perform critical functions such as bearer conversion and security key updates in the CU-DU architecture.
Innovation Solution
A layer 2 processing method is introduced where the CU sends channel reconstruction instruction information to the DU, receives a response message, generates an RRC reconfiguration message, and sends it to the User Equipment (UE), enabling the CU to control the DU's specific layer 2 behaviors for tasks like bearer conversion and security key updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the CU-DU architecture is introduced to increase network capacity and throughput, then system performance is improved, but the complexity of coordination and control between CU and DU increases
Solution Approach 1:
The base station gNB is segmented into two functional units: CU (Central Unit) and DU (Distributed Unit). The CU handles control plane functions including RRC, mobility management, and security, while the DU handles user plane functions including radio bearer management and data transmission. This segmentation allows independent optimization of each unit and reduces overall system complexity.
Solution Approach 2:
A standardized interface is introduced between the CU and DU to mediate their interaction. This interface defines explicit protocols for control messages, user data transmission, and coordination procedures, thereby reducing the complexity of direct coordination and enabling independent development and deployment of each unit.
2Adaptability or versatility
If the CU and DU are separated into different functional units, then system flexibility and deployability are improved, but the complexity of inter-unit communication and coordination increases
Solution Approach 1:
The CU-DU interface is designed with universal protocols that can handle multiple functions including control signaling, user data transmission, and coordination messages. This multi-functional interface reduces the need for separate communication channels and simplifies the overall system architecture.
Solution Approach 2:
The standardized interface acts as an intermediary that abstracts the complexity of inter-unit communication. It provides a uniform method for the CU and DU to exchange information regardless of their specific implementations, thereby improving flexibility and deployability while managing communication complexity.
3Reliability
If explicit cooperation protocols between CU and DU are established, then the reliability of critical functions is improved, but the system complexity increases
Solution Approach 1:
The patent establishes predefined protocols and procedures for critical functions such as bearer conversion and security key updates. These protocols are configured in advance and follow standardized sequences, ensuring reliable execution while reducing the need for complex real-time decision-making and coordination logic.
Solution Approach 2:
The cooperation protocols between CU and DU incorporate feedback mechanisms where each unit confirms receipt and execution of commands. This ensures reliable execution of critical functions while maintaining manageable protocol complexity through structured acknowledgment and error handling procedures.
Data Source
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AI summary
A layer 2 processing method, a CU and a DU are provided. The layer 2 processing method includes: sending channel reconstruction indication information to the DU; receiving a response message sent by the DU; generating an RRC reconfiguration message based on the response message; and sending the RRC reconfiguration message to a UE, and performing, by the UE, a corresponding operation.