Uplink Path Switching in Dual-Connectivity Mobility
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Solution Overview
Problem
In dual-connectivity mobility procedures, user equipment (UE) often experiences interruptions or delays in sending uplink data due to late path switching from a source cell to a target cell, primarily due to limited capabilities or network complexity.
Innovation Solution
A path switching method and device that allow the UE to switch the sending path of uplink data from a source cell to a target cell based on specific conditions, such as successful switching, successful secondary cell group change, or successful random access, using a target uplink grant managed by the MAC layer, ensuring timely path switching and reducing the likelihood of data interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE waits for traditional switching confirmation before switching the uplink data path, then the switching accuracy is improved, but the switching time is delayed causing data interruption or delay
Solution Approach 1:
The UE switches the uplink data path to the target cell in advance based on the downlink path switching confirmation, before traditional uplink switching confirmation is received. This preliminary action allows the UE to prepare the uplink path ahead of time, reducing switching delay while maintaining accuracy through subsequent confirmation steps.
Solution Approach 2:
The patent introduces a buffer mechanism where the UE maintains both source and target cell connections temporarily, allowing data to be routed through either path during the transition period. This cushioning approach prevents data interruption while the path switching is being finalized.
2Reliability
If the UE maintains connections to both source and target cells simultaneously, then the reliability of data transmission is improved, but the device complexity increases
Solution Approach 1:
The UE dynamically adjusts the number and state of active connections based on the switching phase. During the transition period, both source and target connections are maintained with specific roles (source for ongoing data, target for incoming data). After switching confirmation, the source connection is released. This dynamic connection management maintains reliability during transition while reducing complexity in steady state.
3Productivity
If the UE switches the uplink path earlier based on downlink path switching, then the productivity of data transmission is improved, but the risk of premature switching increases causing data errors
Solution Approach 1:
The patent implements a feedback mechanism where the UE monitors for downlink path switching confirmation from the network before executing uplink path switching. The network provides explicit feedback signals that confirm the appropriate timing for uplink switching, ensuring that premature switching does not occur while still enabling timely path transition to maintain productivity.
Data Source
AI summary
A method includes: switching a sending path of uplink data from a source cell to a target cell based on a first condition or a target uplink grant, where the first condition includes: switching the sending path in a case of successful switching, switching the sending path when a secondary cell group SCG is changed successfully, switching the sending path when random access of the target cell succeeds in a switching process, or switching the sending path when random access of the target cell succeeds in an SCG change process; the target uplink grant is an uplink grant that is used for the target cell and that is used by a MAC layer of the UE when a predetermined condition is met.