SCell TA Timer Control via PCell Sync Dependency
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Solution Overview
Problem
In LTE networks, the existing Time Alignment (TA) timer management for secondary cells (SCells) can lead to inefficiencies and increased complexity when the primary cell (PCell) TA timer expires, causing SCell TA timers to start unnecessarily, resulting in synchronization issues and increased workload for both user equipment and radio base stations.
Innovation Solution
Preventing the TA timer associated with the SCell from starting if the PCell TA timer is not running, thereby aborting ongoing random access procedures and ensuring that the SCell TA timer is only restarted when the PCell TA timer is active, thus maintaining synchronization and reducing workload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the SCell TA timer is allowed to start independently when the PCell TA timer expires, then the SCell can maintain independent timing alignment, but this causes synchronization issues and increased workload for user equipment and radio base stations
Solution Approach 1:
The patent merges the SCell TA timer management with the PCell TA timer by preventing the SCell TA timer from starting when the PCell TA timer is not running. This combines the timing alignment control of primary and secondary cells, reducing the number of independent timers that need to be managed and resolving the contradiction between maintaining timing alignment and reducing device complexity.
2Productivity
If the SCell TA timer starts when the PCell TA timer expires, then the SCell can continue timing alignment procedures, but this results in unnecessary timer activation and reduced downlink scheduling efficiency
Solution Approach 1:
The patent applies preliminary anti-action by preventing the SCell TA timer from starting in advance, before any potential synchronization issues can occur. By checking the PCell TA timer status before allowing SCell TA timer activation, the system avoids unnecessary timer activations that would reduce downlink scheduling efficiency and waste time.
3Reliability
If multiple TA timers are allowed to run independently, then each cell can maintain independent synchronization, but this increases the workload for both user equipment and radio base stations
Solution Approach 1:
The patent merges the operation of PCell and SCell TA timers by establishing a dependency relationship where the SCell TA timer cannot run independently without the PCell TA timer. This reduces the effective number of independent timers from two to one, thereby reducing the workload for both user equipment and base station while maintaining necessary synchronization through the PCell.
Data Source
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AI summary
Embodiments herein relate to a method performed by a user equipment (10) for controlling a time alignment timer associated with at least one secondary cell, SCell, wherein the user equipment (10) being configured with a primary cell, PCell, and the at least one SCell. The user equipment (10) prevents a TA timer associated with the at least one SCell from starting if a TA timer associated with the PCell is not running.