Uplink Timing Control in Carrier Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In communication systems using carrier aggregation, managing uplink transmission timings across multiple frequencies is inefficient due to the lack of effective methods for reconfiguring transmission timing timers and reference cells, leading to inefficient radio resource usage.
Innovation Solution
The solution involves a method for efficiently controlling uplink transmission timings by reconfiguring transmission timing timers and reference cells within transmission timing groups, allowing for seamless handovers and modifications of serving cells, using RRC signaling to manage these changes and ensure timely alignment of uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission timing timers and reference cells are not reconfigured during cell handovers in carrier aggregation, then device complexity is reduced, but radio resource utilization becomes inefficient
Solution Approach 1:
The patent applies preliminary action by reconfiguring transmission timing timers and reference cells in advance during cell handover procedures. When a handover is initiated, the network device updates the timing advance group configurations, timer values, and reference cell associations before the actual handover completes, ensuring that uplink transmission timing is already optimized when the user equipment switches cells. This prevents timing mismatches and maintains efficient radio resource utilization throughout the handover process.
2Reliability
If transmission timing timers are extended to maintain longer timing alignment, then uplink transmission reliability is improved, but radio resource efficiency deteriorates due to prolonged timing groups
Solution Approach 1:
The patent implements dynamics by making transmission timing timer durations adaptive rather than fixed. The network device dynamically adjusts the timing advance timer values based on current radio conditions, cell characteristics, and user equipment mobility patterns. When channel conditions are stable, longer timers maintain timing alignment with minimal resource overhead. When conditions change or handovers are detected, the network shortens timers and triggers timely reconfiguration, ensuring reliable uplink transmission while optimizing radio resource utilization by avoiding unnecessarily prolonged timing groups.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is a terminal apparatus (1) that is connected to a base-station apparatus (2) by aggregating a plurality of cells. The terminal apparatus groups cells of different frequencies on the basis of a configuration of a transmission timing group which is notified from the base-station apparatus (2), configures a timing reference cell that is used as a reference of an uplink transmission timing of the cells in the group, a group identifier that identifies the group, and a transmission timing timer that indicates available time of the uplink transmission timing of the cells in the group for each group, and releases the configuration of the transmission timing group corresponding to the group in a case where the timing reference cell does not exist in the group due to a modification in a cell on the basis of a modification instruction message which is transmitted from the base-station apparatus (2) and which gives an instruction of changing the cells in the group.