Enhanced MBB Handover Mechanism for Zero-Millisecond Interruption
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Solution Overview
Problem
Current wireless communication systems, such as LTE and NR, face challenges in achieving zero or near-zero milliseconds of data interruption during handover procedures, as existing enhanced Make Before Break (MBB) mechanisms still cause delays due to disconnection from the source base station before accessing the target base station.
Innovation Solution
Implementing an enhanced MBB mechanism that allows user equipment (UE) to maintain data transmission connections with both the source and target base stations during the handover process, enabling simultaneous uplink path switching from the source cell to the target cell through Radio Resource Control (RRC) configuration and uplink path management operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE disconnects from the source base station before accessing the target base station during handover, then the handover procedure can be completed, but data transmission interruption and delay occur
Solution Approach 1:
The UE performs preliminary actions by establishing the uplink path to the target cell before disconnecting from the source cell. The handover command includes RRC configuration information that pre-configures the uplink path parameters (such as uplink grant, physical uplink shared channel resources) for the target cell, allowing the UE to switch uplink transmission to the target cell without interruption or with minimal interruption.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that data transmission continues uninterrupted during handover. The UE keeps the data transmission connection to the source base station active while simultaneously establishing the uplink path to the target base station, allowing seamless switching without breaking the data transmission flow.
2Reliability
If the UE maintains connection to both source and target base stations simultaneously, then data transmission continuity is improved, but system complexity increases
Solution Approach 1:
The patent segments the connection management by separating downlink and uplink path management. The downlink path continues to use the source cell during handover, while the uplink path is switched to the target cell. This segmentation allows the UE to maintain data transmission continuity without managing full dual-connection complexity, as only the uplink path needs to be reconfigured while the downlink remains stable.
3Speed
If the UE switches uplink path to target cell during random access procedure, then handover speed is improved, but access reliability may deteriorate
Solution Approach 1:
The UE performs preliminary configuration of the uplink path to the target cell by receiving RRC configuration information in the handover command before actually switching. This pre-configuration includes setting up uplink grant parameters and physical uplink shared channel resources, so that when the UE needs to switch during random access, the path is already prepared and can be activated immediately without compromising access reliability.
Data Source
AI summary
Provided in the present invention are a cell handover method and user equipment. The cell handover method comprises: the UE receiving a handover command for instructing the UE to perform an enhanced handover mechanism; performing, on the basis of a Radio Resource Control (RRC) configuration included in the handover command, RRC configuration operations corresponding to communication between the UE and a source cell and communication between the UE and a target cell; the UE performing access to the target base station while maintaining a data transmission connection to the source base station; and the UE performing an uplink path switching operation on a data radio bearer (DRB) configured with the enhanced handover mechanism, and switching an uplink transmission path from the source cell to the target cell for the DRB.