DRX Grant Scheduling Using Retransmission Active Time

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Solution Overview

Problem

The DRX mechanism in existing technologies leads to data transmission delays, particularly for delay-sensitive services like voice services, due to the terminal not listening to the PDCCH during sleep periods, resulting in increased scheduling delays.

Innovation Solution

The method extends the active time in the DRX cycle by utilizing retransmission active times and activation extension times for initial data transmission, allowing for uplink and downlink data transmission even during sleep periods, thereby reducing delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the terminal does not listen to the PDCCH in the sleep period to reduce power consumption, then power saving performance is improved, but data transmission delay increases

Engineering Contradiction:
Improvepower consumptionVSAvoiddata transmission delay
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing initial transmission grant in the retransmission active time window before the terminal would normally go to sleep. This allows data transmission to be initiated in advance during a period when the terminal is still active and listening to PDCCH, thereby reducing transmission delay while maintaining power-saving benefits through subsequent sleep periods.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If the RAN device performs scheduling grant only in the next active period after the sleep period, then power consumption is reduced, but scheduling delay increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidscheduling delay
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The patent applies dynamics by dynamically adjusting the scheduling timing to utilize the retransmission active time window. Instead of rigidly waiting for the next active period, the system dynamically schedules transmissions during the retransmission active time when the terminal is still monitoring PDCCH, thereby reducing scheduling delay while maintaining energy efficiency.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the DRX cycle is configured with separate active and sleep periods, then power saving performance is improved, but data transmission efficiency deteriorates

Engineering Contradiction:
Improvepower saving performanceVSAvoiddata transmission efficiency
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent applies preliminary action by utilizing the retransmission active time window - a period when the terminal is still active after receiving downlink data - to perform additional initial transmissions. This preliminary utilization of the active period improves data transmission efficiency without requiring the terminal to remain active longer, thus preserving power saving performance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies continuity of useful action by extending data transmission opportunities into the retransmission active time window. This allows the system to continuously utilize the terminal's active state for productive data transmission rather than letting the terminal go to sleep immediately after receiving downlink data, thereby improving overall transmission efficiency while maintaining the DRX power-saving structure.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4002926B1Data transmission method, terminal, and ran device
Publication Date: 2025.11.12 HUAWEI TECH CO LTD
  • EP4002926B1 patent drawingFigure 1~2
  • EP4002926B1 patent drawingFigure 3~4
  • EP4002926B1 patent drawingFigure 5

AI summary

The present invention provides a data transmission method, a terminal, and a RAN device to resolve a problem of data transmission delay in a DRX mechanism in the prior art. The method is: sending, by a RAN device to a terminal in a DRX active period, first grant information that is used to perform initial transmission grant for first data; sending, to the terminal in a retransmission active time in which the terminal expects to receive a retransmission grant for the first data, second grant information that is used to perform initial transmission grant for second data; and remaining, by the RAN device and the terminal, in an active state in an activation extension time that is after sending of the second grant information. The initial transmission grant may be uplink initial transmission grant or downlink initial transmission grant. In this way, the RAN device may perform initial transmission by using an uplink retransmission active time or a downlink retransmission active time, so as to extend an active time, which not only ensures use of a DRX technology, but also reduces impact of a delay.