Dual Connectivity Data Retransmission via CU/DU Link Switching
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Solution Overview
Problem
In existing 5G network architectures with CU/DU separation, when a downlink data transmission link of a DU experiences quality deterioration, the network side cannot actively adjust to reduce data transmission delay or packet loss.
Innovation Solution
A method and apparatus that enable a source base station to detect link quality degradation, determine and retransmit data unsuccessfully transmitted by the DU through a target base station, using a downlink data frame with a 'retransmission data indication' field to prioritize such data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CU sends data unsuccessfully transmitted by a source DU to a target DU for retransmission, then data transmission reliability is improved, but the target DU cannot identify whether the data is retransmitted data or newly transmitted data and arranges the data at the end of a sending queue, resulting in increased data transmission delay
Solution Approach 1:
The patent introduces a 'retransmission data indication' field in the downlink data frame that acts as a marker or indicator to distinguish retransmitted data from newly transmitted data. This indication field allows the target DU to identify and prioritize retransmitted data, preventing it from being queued at the end and thus reducing transmission delay while maintaining reliability
Solution Approach 2:
The patent introduces an intermediary mechanism (the indication field and associated processing logic) between the CU and target DU to facilitate proper handling of retransmitted data. This intermediary enables the target DU to correctly identify and process retransmitted data packets, resolving the contradiction between reliable retransmission and timely delivery
2Device complexity
If the network side does not actively adjust when a downlink data transmission link experiences quality deterioration, then system complexity is reduced, but data transmission delay increases and packet loss occurs
Solution Approach 1:
The patent implements a feedback mechanism where the source DU monitors link quality and reports to the CU when deterioration is detected. The CU then actively responds by redirecting data transmission to alternative DUs with better link quality. This feedback loop enables proactive adjustment that reduces delay and packet loss without requiring complex centralized control of all transmission decisions
Solution Approach 2:
The patent introduces dynamic adaptation in the network behavior - when link quality deteriorates, the system automatically adjusts by switching data transmission paths from the affected DU to alternative DUs. This dynamic response allows the network to optimize performance in real-time based on actual link conditions, reducing delay and loss without permanent complexity
3Ease of operation
If data is not retransmitted when link quality deteriorates, then system operation is simplified, but packet loss increases
Solution Approach 1:
The patent implements preliminary action by having the source DU monitor link quality in advance and report deterioration to the CU before significant packet loss occurs. The CU then proactively redirects data transmission to alternative DUs, preventing packet loss before it happens. This preliminary detection and response mechanism maintains simplicity while preventing loss
Solution Approach 2:
The patent provides beforehand cushioning by maintaining alternative transmission paths ready and available. When link quality deteriorates, the CU can immediately switch to alternative DUs that have buffered capacity or better link conditions, cushioning against potential packet loss without requiring complex real-time recovery operations
Data Source
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AI summary
Provided are a data transmission method and apparatus. The method includes: detecting, by a source base station, that link quality of a connection with a terminal degrades; sending data unsuccessfully transmitted by a DU via a downlink data frame to a target base station through a CU, and transmitting the data unsuccessfully transmitted to the terminal through the target base station; or receiving, by the target base station, a link quality degradation message of an original base station so as to stop sending offload data to the source base station and transmitting the data unsuccessfully transmitted indicated by a maximum serial number of the data which has been transmitted continuously and successfully in the message to the terminal. A problem that in a base station dual connectivity technology in the related art, when a base station uses a CU/DU separated structure, even if quality of a DU downlink data transmission link is deteriorated, a network side cannot actively take measures to perform relevant adjustments, thereby resulting in an increase in data transmission delay or even packet loss is solved, thereby reducing data transmission delay, reducing packet loss, and improving user experience.