DU Handover Tunnel Switching for Continuous Downlink Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the CU-CP/CU-UP separated scenario of a base station, the frequent intra-gNB-CU handovers lead to long-term data transmission interruptions due to the CU-UP switching downlink tunnels without immediate connection from the target DU, affecting user experience.
Innovation Solution
A handover method involving CU-CP sending a notification with tunnel switching and holding indication information to CU-UP, allowing continued data transmission through the source downlink tunnel until the target DU connection is established, reducing interruption time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the CU-UP switches the downlink tunnel from source DU to target DU immediately upon handover request, then the handover process is completed faster, but data transmission interruption time increases because the target DU may not be ready to receive data immediately
Solution Approach 1:
The CU-UP performs preliminary actions by continuing to send data through the source downlink tunnel after receiving the handover request, before the target DU is fully ready. This preliminary data transmission through the source tunnel ensures no data loss during the handover transition period, resolving the contradiction between fast handover execution and continuous data transmission.
2Reliability
If the CU-UP continues sending data through the source downlink tunnel during handover, then data transmission continuity is maintained, but the handover efficiency decreases due to delayed tunnel switching
Solution Approach 1:
The patent implements dynamic tunnel switching where the CU-UP flexibly transitions from the source downlink tunnel to the target downlink tunnel based on real-time handover progress. The system dynamically adjusts the data transmission path: initially continuing through the source tunnel for reliability, then switching to the target tunnel once ready, optimizing both continuity and efficiency.
3Adaptability or versatility
If the source DU stops sending data immediately upon handover request, then resources are freed for the target DU, but data transmission interruption occurs until the target DU is ready
Solution Approach 1:
The CU-UP maintains continuous useful action by persisting data transmission through the source downlink tunnel during the handover transition period. This continuous transmission ensures that data flow never stops, bridging the gap between source DU and target DU readiness, thereby eliminating data transmission interruption while maintaining resource allocation flexibility.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed in the present application are a handover method and apparatus, relating to the technical field of communications, and being used for reducing the interruption time of data transmission in a distributed unit DU handover process when the central unit control plane/central unit user plane CU-CP/CU-UP in a base station are separated, enhancing the user experience. In the handover method provided in the embodiments of the present application, a notification sent by the CU-CP to the CU-UP not only carries tunnel switching instruction information, but also comprises maintenance instruction information, the maintenance instruction information instructing the CU-UP to continue sending downlink data by means of the original downlink tunnel, such that downlink data can still be received when the user device is not yet connected to a target DU, thereby reducing the interruption time of data transmission during the DU handover process, and enhancing the user experience.