Target Cell Timing Advance for Low-Latency Handover
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Solution Overview
Problem
Conventional cell handover technologies result in significant delays due to the terminal device obtaining necessary information after receiving the handover command, which is inadequate for low-latency and high-capacity services like XR and cloud gaming.
Innovation Solution
The method involves the terminal device receiving information on how to obtain timing advance (TA) of a candidate cell before the handover command, allowing it to synchronize with the target cell and perform uplink communication immediately upon handover, using various signaling methods such as RAR, cell handover command, or independent signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the terminal device obtains target cell information after receiving the handover command, then the handover process is simple, but the handover delay increases
Solution Approach 1:
The terminal device performs downlink synchronization, uplink synchronization, beam management, and channel quality measurement on the target cell before receiving the handover command. This preliminary action allows the terminal to have target cell information ready in advance, eliminating the need to perform these operations after handover, thus reducing handover delay while keeping the process manageable
2Loss of time
If the terminal device completes information obtaining before receiving the handover command, then the handover delay is reduced, but the device complexity increases
Solution Approach 1:
The terminal device performs downlink synchronization, uplink synchronization, beam management, and channel quality measurement on the target cell before receiving the handover command. This preliminary action allows the terminal to have target cell information ready in advance, eliminating the need to perform these operations after handover, thus reducing handover delay while keeping the process manageable
3Reliability
If multiple synchronization and measurement operations are performed before handover, then the communication quality is improved, but the device complexity increases
Solution Approach 1:
The terminal device performs downlink synchronization, uplink synchronization, beam management, and channel quality measurement on the target cell before receiving the handover command, ensuring communication quality is established in advance
Solution Approach 2:
The patent introduces dynamic parameters including a validity duration for pre-obtained target cell information and a timer mechanism. The network can configure the terminal to update target cell information periodically or based on specific triggers, making the system adaptable to changing channel conditions while managing complexity through configurable parameters
Data Source
AI summary
This application provides a communication method and a communication apparatus. The method includes: receiving first information, where the first information indicates a manner of obtaining a timing advance (TA) of a first cell; and obtaining the TA of the first cell based on the first information. According to the technical solution provided in this application, the obtaining manner of obtaining the TA of the first cell is configured for the terminal apparatus based on the first information. Therefore, before receiving a cell handover command, the terminal apparatus may obtain the TA of the first cell in the manner indicated by the first information, to complete uplink synchronization with the first cell. Therefore, after the terminal apparatus is handed over to the first cell, it may no longer perform the uplink synchronization process. Therefore, a handover delay of handover to the first cell can be reduced.