GTP-U Sequence Mapping for Complete Multicast Handover Delivery
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Solution Overview
Problem
Data loss occurs during handover of a terminal from a source cell to a target cell in multimedia broadcast and multicast services due to asynchronous data transmission between the two cells, leading to incomplete data reception by the terminal.
Innovation Solution
A data retransmission method involving a target node that obtains a mapping relationship between GTP-U sequence numbers and source PDCP sequence numbers, allowing for data retransmission based on this mapping to ensure complete data delivery to the terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If asynchronous data transmission is used between source cell and target cell during handover, then handover speed is improved, but data completeness deteriorates
Solution Approach 1:
The source cell performs preliminary actions by determining which data packets need to be retransmitted and sends notifications to the target cell before the handover is complete. This allows the target cell to prepare for retransmission in advance, ensuring data completeness while maintaining fast handover speed.
Solution Approach 2:
A notification mechanism acts as an intermediary between the source cell and target cell. The source cell sends retransmission notifications containing packet information to the target cell, which then uses this information to perform accurate retransmission, resolving the data completeness issue without sacrificing handover speed.
2Reliability
If data retransmission is performed after handover, then data completeness is improved, but handover time increases
Solution Approach 1:
The source cell determines the retransmission packet list and sends notifications to the target cell during the handover process itself, rather than after handover completes. This preliminary preparation eliminates additional handover time while ensuring data completeness through subsequent retransmission.
Solution Approach 2:
The retransmission process is integrated into the handover procedure through continuous notification and coordination between source and target cells. This continuous action ensures data completeness is achieved without interrupting or extending the handover time, as the retransmission preparation occurs concurrently with handover execution.
Data Source
AI summary
Data retransmission method is disclosed. The method includes: obtaining a mapping relationship between GTP-U sequence numbers of N data packets sent by a source node and source PDCP sequence numbers assigned to the N data packets by the source node; and performing data retransmission based on the mapping relationship.