Terminal Random Access Timing for Pending SR and TA Expiry

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Solution Overview

Problem

In communication systems, when a scheduling request (SR) remains pending due to an invalid timing advance (TA) value, the terminal device's behavior is unclear, leading to unnecessary waiting and reduced communication efficiency.

Innovation Solution

The terminal device initiates a random access procedure at or before the time when the TA value becomes invalid, within a configured time window where the network device does not receive uplink signals, to avoid unnecessary waiting and reduce latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the terminal device waits until the TA value becomes invalid before initiating random access, then the SR configuration and counter can be retained, but data transmission latency increases due to unnecessary waiting

Engineering Contradiction:
Improvedata transmission latencyVSAvoidSR pending state handling reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The terminal device initiates the random access procedure at or before the first time when the TA value becomes invalid, rather than waiting until after it becomes invalid. This preliminary action eliminates unnecessary waiting time and reduces data transmission latency while ensuring reliable handling of the SR pending state.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the terminal device initiates random access after the TA value becomes invalid, then the procedure is simpler to implement, but communication efficiency decreases due to prolonged waiting times

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidterminal device behavior complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The terminal device determines the first time when the TA value becomes invalid and initiates random access at or before this time point. This approach improves communication efficiency by reducing waiting time while maintaining clear implementation criteria based on the TA value invalidation timing.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If the terminal device pauses SR sending during the first time window, then network energy saving is achieved, but SR transmission is delayed until the window ends

Engineering Contradiction:
Improvenetwork energy consumptionVSAvoidSR transmission delay
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The terminal device initiates random access at or before the first time when the TA value becomes invalid (which occurs during the first time window when the network does not receive uplink signals). This allows the random access procedure to start while the network is in energy-saving mode, avoiding SR transmission delays while still achieving network energy saving.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4712622A1Communication method and terminal device
Publication Date: 2026.03.18 QUECTEL WIRELESS SOLUTIONS CO LTD
  • EP4712622A1 patent drawingFigure 1~3
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  • EP4712622A1 patent drawingFigure 6~7

AI summary

A method for communication and a terminal device are provided. The method includes: triggering, by a terminal device, a random access procedure at or before a first time when a timing advance (TA) value becomes invalid, if the first time is within a first time window and a scheduling request, SR, in a pending state exists. The first time window is a time window during which a network device does not receive uplink signals. If the terminal device initiates, in response to the invalidation of the TA value, the random access procedure until it is about to send the SR after the first time window, it will result in unnecessary waiting by the terminal device. However, in the present disclosure, the terminal device initiates the random access procedure at or before the first time when the TA value becomes invalid. Therefore, the time for initiating the random access procedure in the present disclosure is earlier, which can avoid unnecessary waiting by the terminal device, thereby reducing data transmission latency and improving communication efficiency.