Source Base Station SN Determination for Handover Data
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Solution Overview
Problem
During enhanced base station handover, the source base station cannot determine the Sequence Number (SN) of the first data packet received by the target base station that is not associated with the SN, due to the simultaneous connection with both base stations.
Innovation Solution
The source base station sends first information including a data packet group and PDCP SN to the target base station, allowing it to determine the SN of the first received data packet not associated with the PDCP SN by sending second information, such as indication signaling or a preset value, enabling the target base station to number the packets appropriately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the terminal device maintains connection with both source base station and target base station simultaneously during enhanced handover, then handover time delay is reduced, but the source base station cannot determine the SN value of the first data packet received by the target base station that is not associated with SN
Solution Approach 1:
The source base station performs preliminary actions by determining the SN value of the first data packet received by the target base station that is not associated with SN, and sends this determined SN value to the target base station before the target base station needs to use it. This allows the target base station to have the SN information ready in advance, resolving the contradiction between maintaining simultaneous connections (reducing handover delay) and determining SN values (which would otherwise be lost).
Solution Approach 2:
The source base station acts as an intermediary between the data transmission process and the target base station. It receives data packets from the terminal device, determines the SN values for packets not associated with SN, and provides this information to the target base station. This intermediary role resolves the information loss at the target base station while maintaining the enhanced handover connection structure.
2Productivity
If the source base station sends data packets to the target base station during enhanced handover, then data transmission continuity is maintained, but the target base station cannot properly number packets without SN association
Solution Approach 1:
The source base station performs preliminary determination of SN values for data packets before forwarding them to the target base station. By calculating and providing the SN values in advance, the source base station ensures that the target base station receives both the data packets and their corresponding numbering information simultaneously, maintaining both transmission continuity and numbering accuracy.
Solution Approach 2:
The source base station provides feedback information to the target base station regarding the SN values of transmitted data packets. This feedback mechanism ensures that the target base station has accurate numbering information for all received packets, resolving the contradiction between maintaining continuous transmission and ensuring accurate packet numbering.
Data Source
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AI summary
Provided are a wireless communication method and apparatus, and a network device. The method comprises: if a cell handover occurs in a terminal device, a source cell sending first information to a target cell, wherein the first information comprises at least one first PDCP SN and a first data packet group, and the first data packet group comprises at least one first data packet; and the source cell sending second information to the target cell, such that the target cell determines, according to the second information, a second PDCP SN associated with a second data packet, wherein the second data packet is a data packet that is the first, not associated with the first PDCP SN, of the data packets that are received by the target cell. In the method provided in the present application, where a cell handover occurs in a terminal device, a source cell can send second information to a target cell, such that the target cell can determine, according to the second information, a second PDCP SN of a second data packet received by the target cell.