5G Base Station DU-CU Wireless Connection Control
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Solution Overview
Problem
In the 5G system, the separation of base station functions into centralized and distributed units poses challenges in processing the RRC connection establishment process, as existing methods cannot directly handle the interaction between the distributed unit (DU) and the centralized unit (CU) for wireless connection control.
Innovation Solution
A wireless connection control method is introduced where the distributed unit receives a message from a terminal requesting an air interface control plane connection, forwards it to the centralized unit, and receives instructions to establish the connection, enabling efficient communication and processing between the DU and CU for wireless connection control in a 5G system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If base station functions are separated into centralized unit (CU) and distributed unit (DU), then network scalability and cost are improved, but the complexity of processing RRC connection establishment increases due to required interaction between CU and DU
Solution Approach 1:
The base station is segmented into two functional units: a centralized unit (CU) that handles higher-layer protocol processing (RRC, PDCP) and a distributed unit (DU) that handles lower-layer protocol processing (RLC, MAC, physical layer). This segmentation enables network scalability by allowing multiple DUs to share a single CU, while clearly defining the interface and interaction protocols between the two units for connection establishment processing.
2Adaptability or versatility
If RRC connection establishment is processed through interaction between DU and CU, then functional separation is achieved, but processing time and signaling overhead increase
Solution Approach 1:
The distributed unit (DU) performs preliminary actions by receiving the RRC connection establishment request from the terminal and forwarding it to the centralized unit (CU) without waiting for the terminal to complete the entire connection process. The CU prepares connection resources in advance and sends establishment instructions back to the DU, enabling parallel processing and reducing overall connection establishment time.
3Ease of manufacture
If multiple DUs share one CU, then cost is reduced and scalability is improved, but the complexity of managing control plane connections increases
Solution Approach 1:
The centralized unit (CU) acts as an intermediary that manages control plane connections for multiple distributed units (DUs). The CU receives control plane messages from terminals through any connected DU, processes them centrally, and sends appropriate responses back through the same or different DUs. This intermediary approach allows cost-effective sharing of CU resources across multiple DUs while the CU itself manages the complexity of coordinating control plane connections.
Data Source
AI summary
This application provides a wireless connection control method relating to a base station system including a centralized unit and a distributed unit, wherein the centralized unit communicates with the distributed unit, and the distributed unit communicates with a terminal through an air interface. The method includes: first receiving, by the distributed unit, a first message sent by the terminal, where the first message is used to request to establish an air interface control plane connection for the terminal; then sending, by the distributed unit, the first message to the centralized unit; and then receiving, by the distributed unit, a second message sent by the centralized unit, where the second message is used to instruct to establish the air interface control plane connection between the terminal and the distributed unit. The method may implement wireless connection control in a 5G system when functions of a base station are separated.