UE TAT Suspend Resume for DTX DRX Sync

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Solution Overview

Problem

In wireless communication networks, particularly in 5G NR systems, the expiration of the Time Alignment Timer (TAT) during cell Discontinuous Transmission (DTX) or Discontinuous Reception (DRX) operations leads to unnecessary burdens on User Equipment (UE) and Base Stations (BS), requiring procedures to handle out-of-sync conditions.

Innovation Solution

The method involves configuring the UE to suspend and resume the TAT based on the cell DTX/DRX operation periods, allowing the UE to consider itself uplink synchronized even after TAT expiration during non-active periods, thereby forgoing procedures for handling out-of-sync conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the TAT is configured to expire during DTX/DRX non-active periods, then the UE can save power by not monitoring during these periods, but the UE and BS incur unnecessary overhead from handling out-of-sync conditions

Engineering Contradiction:

ImproveUE power consumptionVSAvoidOverhead from handling out-of-sync conditions

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the TAT behavior adaptive to the DTX/DRX operational state. The UE dynamically adjusts TAT expiration handling based on whether it is in active or non-active period, suspending TAT during non-active periods and resuming during active periods, thereby optimizing power consumption while avoiding unnecessary overhead

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameter of TAT based on DTX/DRX state. By modifying TAT behavior (suspend/resume) according to the network's transmission/reception state, the system achieves energy efficiency without triggering unnecessary out-of-sync handling procedures

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the UE performs procedures to handle TAT expiration during DTX/DRX operations, then uplink synchronization can be maintained, but device complexity and processing burden increase

Engineering Contradiction:

ImproveUplink synchronizationVSAvoidUE processing procedures

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The UE dynamically adjusts its processing behavior based on the DTX/DRX state. During non-active periods, the UE suspends TAT and avoids complex out-of-sync handling procedures. During active periods, the UE resumes TAT monitoring, thereby maintaining uplink synchronization reliability while reducing device complexity and processing burden during low-activity periods

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If the TAT is suspended during DTX/DRX non-active periods, then overhead and power consumption are reduced, but timing alignment management becomes more complex

Engineering Contradiction:

ImproveOverhead from TAT expiration handlingVSAvoidTAT suspension and resumption management

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements dynamic TAT management by suspending the timer during DTX/DRX non-active periods and resuming it during active periods. This dynamic approach reduces overhead and power consumption associated with TAT expiration handling while the suspension/resumption mechanism itself manages the added complexity of timing alignment

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250056459A1Method and apparatus for handling timing alignment in wireless networks

Publication Date: 2025.02.13 SHARP KK

AI summary

A method performed by a User Equipment (UE) for handling timing alignment is provided. The method receives, from a Base Station (BS), a first Radio Resource Control (RRC) message for configuring a Time Alignment Timer (TAT). The method receives, from the BS, a second RRC message for configuring at least one of a cell Discontinuous Transmission (DTX) operation or a cell Discontinuous Reception (DRX) operation. In a case that at least one of the cell DTX operation or the cell DRX operation is configured and the TAT expires, the method considers the UE to be uplink synchronized with the BS and forgoes performing a procedure for handling an out-of-sync condition related to the expiration of the TAT.