Uplink Timing Advance Control During Inter-Cell Switching
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Solution Overview
Problem
In future radio communication systems, the control of uplink transmission timing advance during inter-cell mobility is unclear, leading to potential degradation of communication quality when switching between serving and candidate cells.
Innovation Solution
A terminal equipped with a receiving section for Medium Access Control Control Elements (MAC CE) to judge timing advance for uplink transmission based on information within the MAC CE, which includes fields related to cell switching and timing advance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inter-cell mobility is performed by switching between serving cell and candidate cell, then communication flexibility and mobility support are improved, but timing advance control becomes unclear and communication quality may degrade
Solution Approach 1:
The MAC CE is segmented into distinct functional fields: cell switching fields (first field) and timing advance fields (second field). This segmentation allows the terminal to separately process cell switching commands and timing advance adjustments, ensuring that timing advance control is explicitly maintained during inter-cell mobility transitions, thereby preventing communication quality degradation.
Solution Approach 2:
The timing advance information is prepared and included in the MAC CE in advance of the actual cell switching execution. By providing timing advance values beforehand within the same MAC CE that carries the cell switching command, the terminal can seamlessly transition between cells without timing synchronization issues, maintaining communication quality throughout the mobility process.
2Device complexity
If timing advance is not appropriately indicated during cell switching, then device complexity is reduced, but communication quality and reliability deteriorate
Solution Approach 1:
The cell switching command and timing advance indication are merged into a single MAC CE structure. This combination allows the base station to simultaneously convey both the cell switching instruction and the corresponding timing advance value in one signaling message, reducing overall control signaling complexity while ensuring that timing advance is appropriately indicated during cell switching, thereby maintaining communication quality.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A terminal according to one aspect of the present disclosure includes: a receiving section that receives a Medium Access Control Control Element (MAC CE) related to cell switching; and a control section that judges timing advance (TA) to apply to UL transmission, based on information included in the MAC CE. The MAC CE includes at least one of a field related to cell switching and a field related to the TA. According to one aspect of the present disclosure, even when inter-cell mobility is performed, communication can be appropriately controlled.