User Equipment Timing Advance Timer Drop for Random Access Recovery
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Solution Overview
Problem
In the 3GPP LTE communication system, when a user equipment (UE) fails to successfully request uplink resources due to poor signal quality, the retransmission of scheduling requests (SR) leads to the time alignment timer remaining active, causing the TA command in the random access response message to be ignored, resulting in potential random access contention resolution failures and prolonged connection recovery times.
Innovation Solution
A mechanism where the user equipment drops the time alignment timer after the maximum number of SR transmissions is reached, ensuring the new TA value can be applied during the random access procedure, preventing the TA command from being ignored and facilitating timely connection recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the time alignment timer is kept running after maximum SR transmissions are reached, then the UE maintains timing alignment status, but the TA command in random access response message is ignored causing connection recovery delay
Solution Approach 1:
The patent applies preliminary action by detecting whether the time alignment timer is running before executing the random access procedure, and proactively stopping the timer if it is running. This preliminary intervention prevents the TA command from being ignored during subsequent random access, thereby resolving the contradiction between maintaining timing alignment status and enabling timely connection recovery.
2Stability of the object's composition
If the TA command is ignored during random access procedure, then the UE maintains its current TA value, but the uplink transmission uses obsolete TA value causing random access failure
Solution Approach 1:
The patent implements feedback by monitoring the state of the time alignment timer and using this information to control the execution of random access procedure. When the timer is detected to be running, the UE stops the timer and proceeds with random access, ensuring that the TA command will be applied and received, thereby improving random access success rate while maintaining TA value stability through controlled updates.
3Productivity
If the UE continuously retransmits SR in poor signal conditions, then the UE attempts to maintain uplink resource allocation, but the time alignment timer remains active preventing TA value update
Solution Approach 1:
The patent applies dynamics by making the time alignment timer state conditional and changeable based on the execution context. Instead of continuously running the timer during SR retransmissions, the system dynamically stops the timer when transitioning to random access procedure, allowing the TA value to adapt to current network conditions while maintaining productivity through persistent SR retransmission attempts.
Data Source
AI summary
A user equipment and a timing advance value updating method thereof are provided. The UE determines that a scheduling request transmission counter reaches a maximum number of SR transmission and determines whether a time alignment timer is still running after the scheduling request transmission counter reaches the maximum number of SR transmission. If the time alignment timer is still running, the UE drops the time alignment timer.