User Plane Bearer Switching for Low-Latency Cell Handover
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Solution Overview
Problem
In mobile communication systems, cell handover processes cause delays in data forwarding from a source access network device to a target access network device, leading to invalid data at the terminal device and affecting service experience.
Innovation Solution
The proposed method involves the source central unit initiating the switching of the user plane bearer earlier based on a notification message, reducing or eliminating the need for data forwarding by directly sending service data to the target central unit, and optimizing the association relationships and identifiers to minimize signaling overheads and delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data forwarding from source access network device to target access network device is performed during handover, then data transmission continuity is maintained, but data forwarding delay increases causing data invalidity
Solution Approach 1:
The source CU initiates user plane bearer switching to the target CU before the handover is completed, based on receiving a notification message indicating the terminal device is to be handed over to the target cell. This preliminary action allows the target CU to prepare for data reception in advance, eliminating the need for data forwarding after handover and reducing data forwarding delay.
2Reliability
If user plane bearer switching is initiated after terminal successfully accesses target cell, then handover completion is ensured, but data forwarding delay occurs affecting service experience
Solution Approach 1:
The source CU switches the user plane bearer to the target CU in advance based on a notification message about impending handover, rather than waiting until after the terminal successfully accesses the target cell. This preliminary switching enables the target CU to immediately receive and forward data to the terminal, reducing delay and improving service experience while ensuring handover completion.
3Reliability
If data forwarding process is implemented during handover, then data transmission is maintained, but invalid data is generated at terminal device
Solution Approach 1:
The source CU initiates user plane bearer switching to the target CU before handover completion based on receiving a notification message. This preliminary action ensures that the target CU is ready to receive data immediately, eliminating the need for data forwarding from the source CU. Consequently, all data transmitted to the terminal is valid and current, preventing invalid data generation.
4Loss of time
If early user plane bearer switching is performed based on notification message, then data forwarding delay is reduced, but signaling overhead increases
Solution Approach 1:
The source CU switches the user plane bearer to the target CU in advance based on a notification message about impending handover. This preliminary switching eliminates the need for subsequent data forwarding procedures, reducing data forwarding delay. The signaling overhead is minimized by triggering the switching action early based on existing handover notification messages rather than requiring additional separate signaling exchanges.
Data Source
AI summary
This application provides a handover method and a communication apparatus. Switching of a user plane bearer of a terminal device may be initiated based on a notification message indicating a target cell to which the terminal device is to be handed over. In other words, the switching of the user plane bearer of the terminal device may be triggered by the notification message. The switching of the user plane bearer of the terminal device can be performed earlier than switching of the user plane bearer of the terminal device that is initiated after an indication indicating that the terminal device successfully accesses the target cell is received.