Time Alignment Timer Relaxation for Lower UE Measurement Overhead
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Solution Overview
Problem
Existing wireless communication systems require UEs to perform frequent and unnecessary measurements to maintain timing alignment, leading to increased power consumption and network overhead.
Innovation Solution
UEs are provided with TAT relaxation criteria based on reference signal measurements, allowing them to request and apply TAT relaxation parameters, reducing the frequency of measurements and reports, thereby conserving power and network resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UEs perform frequent measurements to maintain timing alignment, then timing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of measurement frequency based on UE mobility state. The network determines whether a UE is mobile or stationary and applies different TAT values accordingly - shorter TAT for mobile UEs requiring frequent measurements, and longer TAT for stationary UEs allowing reduced measurement frequency, thus optimizing power consumption while maintaining timing accuracy
Solution Approach 2:
The patent changes the TAT parameter based on UE mobility characteristics. By adjusting the TAT value (timing alignment timer), the system controls how long timing alignment information remains valid. For stationary UEs, a longer TAT reduces measurement frequency and power consumption, while mobile UEs receive shorter TAT values to maintain accuracy
2Reliability
If UEs perform frequent measurements to maintain timing alignment, then timing alignment reliability is improved, but network overhead increases
Solution Approach 1:
The system dynamically adjusts measurement reporting frequency based on UE mobility state. Stationary UEs with long TAT values report measurements less frequently, reducing network overhead, while mobile UEs with short TAT values maintain frequent reporting to ensure timing alignment reliability
Solution Approach 2:
By varying the TAT parameter according to UE mobility, the network controls the validity duration of timing alignment information. This parameter change directly influences measurement and reporting frequency, optimizing the balance between timing alignment reliability and network overhead
3Use of energy by moving object
If UEs with stable timing information reduce measurements, then power consumption is reduced, but timing alignment accuracy may deteriorate
Solution Approach 1:
The patent applies different measurement and TAT configurations to different UE groups based on their mobility characteristics. Stationary UEs receive long TAT values allowing reduced measurements, while mobile UEs receive short TAT values requiring frequent measurements. This localized quality adjustment ensures each UE group maintains appropriate timing accuracy while optimizing power consumption
4Reliability
If the network sends frequent timing advance commands, then timing alignment is maintained, but network power consumption increases
Solution Approach 1:
The network dynamically adjusts the frequency of timing advance commands based on UE mobility state. For stationary UEs with long TAT values, the network sends commands less frequently, reducing network power consumption. For mobile UEs with short TAT values, the network maintains frequent command transmission to ensure timing alignment reliability
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of time alignment timer (TAT) relaxation criteria for one or more time alignment timers at the UE. The UE may transmit a request or a status report for TAT relaxation based on satisfying the time alignment timer relaxation criteria. The UE may receive an indication of TAT relaxation parameters in response to the request or status report. The UE may apply the TAT relaxation parameters to perform fewer measurements and transmit fewer measurement reports for uplink transmission. In some cases, reduced physical downlink control channel (PDCCH) monitoring occasions and extended discontinuous reception (DRX) can be jointly configured with the relaxation of TATs for the UE.