Two-Step Random Access DRX Timing for Reliable Low-Power Monitoring

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in managing beam management and discontinuous reception (DRX) operations, particularly in 4G and 5G networks, leading to suboptimal power consumption and resource utilization.

Innovation Solution

A method for wireless devices to transmit messages with a preamble and transport block, determine DRX active times, and adjust monitoring of downlink control channels based on DRX operations, allowing for optimized power saving by stopping unnecessary channel monitoring during inactive times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wireless device continuously monitors downlink control channels to ensure reliable reception of responses, then the reliability of communication is improved, but the power consumption increases

Engineering Contradiction:
Improvereliability of response receptionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements discontinuous reception (DRX) where the wireless device alternates between active monitoring periods and sleep periods. The device monitors downlink control channels only during DRX active time and stops monitoring during DRX inactive time, creating a periodic action pattern that reduces power consumption while maintaining communication reliability through scheduled monitoring intervals.

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If the wireless device stops monitoring downlink control channels during DRX inactive time to save power, then the power consumption is reduced, but the response reception may be missed

Engineering Contradiction:
Improvepower consumptionVSAvoidresponse reception reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses feedback mechanisms where the wireless device determines DRX active time based on timing relationships with transmitted messages. The device calculates when to resume monitoring based on expected response timing, creating a feedback loop that ensures monitoring occurs at critical moments while maintaining power savings during non-critical periods.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The wireless device performs preliminary determination of DRX active time before actually monitoring for responses. By pre-calculating monitoring windows based on message transmission timing and configured DRX parameters, the device prepares in advance to monitor at the right moments, ensuring no responses are missed while minimizing unnecessary monitoring.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the wireless device monitors downlink control channels during all time periods to ensure no messages are missed, then the communication reliability is improved, but the battery life decreases

Engineering Contradiction:
Improvemessage reception reliabilityVSAvoidbattery life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent implements discontinuous reception (DRX) where the wireless device alternates between active monitoring periods and sleep periods. The device monitors downlink control channels only during DRX active time and stops monitoring during DRX inactive time, creating a periodic action pattern that reduces power consumption while maintaining communication reliability through scheduled monitoring intervals.

Inventive Principle:
Principle #19Periodic action

4Speed

If the wireless device activates monitoring before the expected response time to ensure early detection, then the response detection speed is improved, but the power consumption increases

Engineering Contradiction:
Improveresponse detection speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The wireless device performs preliminary determination of DRX active time before actually monitoring for responses. By pre-calculating monitoring windows based on message transmission timing and configured DRX parameters, the device prepares in advance to monitor at the right moments, ensuring no responses are missed while minimizing unnecessary monitoring.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4123915B1Discontinuous reception for a two-step random access procedure
Publication Date: 2025.07.02 OFINNO LLC
  • EP4123915B1 patent drawingFigure 1A~1B
  • EP4123915B1 patent drawingFigure 2A~2B
  • EP4123915B1 patent drawingFigure 3

AI summary

A method for a wireless device is described herein. In accordance with one embodiment, the method includes transmitting - by the wireless device - a message comprising a preamble and a transport block. The method further includes determining that a discontinuous reception (DRX) operation of the wireless device is in a DRX active time based on a time window running, wherein the time window starts at a first symbol of a control resource set of the wireless device that is at least one symbol after a transmission occasion of the transport block; receiving, via one or more downlink control channels and based on the determining, a response to the message; and stopping monitoring the one or more downlink control channels based on a determination that the DRX operation is not in the DRX active time in response to receiving the response. Furthermore, a corresponding method for a base station as well as a respective wireless device, a respective base station and related devices and systems are described herein.