DU RRC Protocol Termination for 5G Base Station Control Plane Delay
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Solution Overview
Problem
The existing 5G base station separation architecture, where the RRC protocol is processed only on the Centralized Unit (CU), leads to increased control plane delay and performance degradation due to the high number of network signaling interactions between the CU and the Distributed Unit (DU) during UE control plane processing, which is not optimized for future wireless network delay requirements.
Innovation Solution
The proposed solution involves terminating the RRC protocol on the DU, moving UE control management functions and radio resource configuration processing flows to the DU, and reducing network interactions by having the CU manage UE context information and control DU operations, allowing the DU to independently complete RRC connection establishment and radio resource admission processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the RRC protocol is processed only on the CU in a base station separation architecture, then the control plane processing follows a standardized protocol stack, but the control plane delay increases significantly due to multiple network signaling interactions between CU and DU
Solution Approach 1:
The patent segments the base station into CU and DU functional entities, but further segments the control plane processing by allowing the DU to independently handle RRC protocol processing and UE control management. This segmentation eliminates the need for multiple signaling interactions between CU and DU for control plane operations, reducing delay while maintaining the architectural separation benefits.
Solution Approach 2:
The patent introduces a direct control plane processing path at the DU that acts as an intermediary between the radio interface and the CU. The DU can independently process RRC messages and manage UE control functions, serving as a local mediator that eliminates the need for round-trip signaling to the CU for control plane operations.
2Device complexity
If the RRC protocol processing is centralized on the CU, then the protocol stack configuration is uniform and manageable, but the number of network signaling interactions increases to at least 5 times for RRC connection establishment
Solution Approach 1:
The patent enables the DU to perform self-service for control plane operations by independently processing RRC protocols and managing UE control functions. The DU can autonomously handle RRC connection establishment, context setup, and handover processes without requiring continuous configuration commands from the CU, thereby improving processing efficiency while maintaining configuration consistency through initial CU-provided parameters.
3Length of stationary object
If the distance between CU and DU is 100km with fiber transmission, then the base station can cover large areas, but each signaling interaction introduces approximately 0.5ms delay
Solution Approach 1:
The patent implements preliminary action by pre-configuring the DU with necessary control plane processing capabilities and RRC protocol stacks. The DU is prepared in advance to independently handle control plane operations, eliminating the need for real-time signaling interactions with the CU during UE access and mobility events, thus reducing the impact of transmission distance on overall delay.
Data Source
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AI summary
Embodiments of the present application provide a communication method under a wireless base station separation architecture, a functional entity and a wireless base station. The method comprises that: a Distributed Unit (DU) provided with all control panel protocol stacks of an air interface receives a Radio Resource Control (RRC) message sent by User Equipment (UE); the DU decodes and identifies the RRC message, so that the RRC protocol is terminated on the DU. The embodiments of the present application also provide a corresponding functional entity and a wireless base station. By means of the embodiments of the present application, the processing delay of a control plane flow can be reduced.