Wireless Uplink Time Alignment Using Segmented TAG Timers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ambiguity arises in uplink time alignment maintenance operations due to the expiration of multiple timing advance group (TAG) timers, leading to frequent and unreliable UL/DL configuration releases, which affect HARQ-ACK transmission and overall system performance.
Innovation Solution
Implement a method for a user equipment (UE) to manage uplink timing alignment using separate timers for primary and secondary TAGs, with defined operations upon timer expiration, including flushing HARQ buffers, releasing specific channels, and maintaining timing advance values, while allowing limited UL transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single time alignment timer is used for all TAGs, then the system operation is simple, but ambiguity arises in uplink time alignment maintenance operations when multiple TAGs are involved
Solution Approach 1:
The patent divides the single time alignment timer into multiple separate timers, each associated with a specific TAG (Timing Advance Group). This segmentation allows each timer to be independently managed and expired, eliminating the ambiguity of determining which TAG's timer expired when multiple TAGs are involved, while maintaining clear and reliable time alignment maintenance operations.
2Reliability
If all UL configurations are released when a time alignment timer expires, then time alignment is maintained, but HARQ-ACK transmission for DL reception is disabled affecting DL operations
Solution Approach 1:
The patent segments the UL configuration release operation by associating each time alignment timer with a specific TAG. When a timer expires, only the UL configurations related to that specific TAG are released, not all UL configurations system-wide. This segmented approach maintains time alignment for the expired TAG while preserving HARQ-ACK transmission capability for other TAGs, thus preventing disruption to DL operations.
3Measurement precision
If time alignment timer expiration operations are performed frequently, then time alignment is maintained accurately, but signaling overhead increases and system performance decreases
Solution Approach 1:
By segmenting the time alignment maintenance into separate timers for different TAGs, the patent enables more targeted and efficient timer management. Each TAG's timer can be independently controlled and expired based on its specific timing requirements, reducing the frequency of system-wide configuration releases. This segmentation reduces unnecessary signaling overhead and energy consumption while maintaining accurate time alignment for each TAG.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A method performed by means of a terminal, according to one embodiment of the present disclosure, comprises the steps of: receiving configuration information related to a timing advance group (TAG) from a base station; performing an operation related to the maintenance of uplink timing alignment on the basis of a time alignment timer; and transmitting, to the base station, an uplink channel/signal on the basis of uplink transmission timing for the TAG.