NR V2X Sidelink DRX Scheduling for Power-Efficient Reception

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Solution Overview

Problem

In sidelink (SL) communication, receiving UEs maintain an active state unnecessarily, leading to power consumption and potential missed transmissions due to limitations in resource reservation intervals exceeding 32 slots, which are not supported by conventional NR V2X release 16 technology.

Innovation Solution

The method involves aligning SL discontinuous reception (DRX) configurations between transmitting and receiving UEs based on resource reservation information in SCI, allowing UEs to transition to sleep mode during inactive periods and ensuring timely reception of subsequent transmissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RX UE maintains active state to monitor all reserved transmission resources, then transmission reliability is improved, but power consumption increases

Engineering Contradiction:
Improvetransmission reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The RX UE dynamically adjusts its reception state based on decoded SCI information. When resource reservation information indicates no transmission in certain intervals, the UE transitions to sleep mode for those intervals, making the reception state adaptive rather than static, thus reducing power consumption while maintaining reliability for actual transmissions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The RX UE periodically wakes up at specific intervals to monitor transmissions based on the resource reservation pattern decoded from SCI. Instead of maintaining continuous active state, the UE activates only during periods when transmissions are expected according to the reserved resource pattern, reducing overall power consumption while ensuring reliable reception

Inventive Principle:
Principle #19Periodic action

2Adaptability or versatility

If resource reservation interval exceeds 32 slots, then transmission flexibility is improved, but reception reliability deteriorates

Engineering Contradiction:
Improvetransmission flexibilityVSAvoidreception reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent extends the resource reservation mechanism into a new dimension by allowing reservation information to indicate resources beyond the traditional 32-slot window. This dimensional extension enables long-interval reservations while maintaining reception reliability through the updated DRX alignment mechanism that can handle extended reservation patterns

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If RX UE stays in active state for all reserved resources, then no transmissions are missed, but power savings are reduced

Engineering Contradiction:
Improvetransmission reception reliabilityVSAvoidpower savings
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The RX UE uses feedback from decoding SCI to determine its active/sleep state. When SCI indicates no transmission in certain reserved resource intervals, the UE receives this feedback and accordingly enters sleep mode, eliminating unnecessary power consumption while maintaining reliability through condition-based state transitions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The RX UE autonomously manages its own power state based on the resource reservation information it decodes from SCI. The UE independently determines when to wake up and when to sleep without continuous network control, achieving power savings through self-directed DRX operation aligned with the transmission pattern

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4277410B1Method and device for performing DRX operation based on resource allocation information in NR v2x
Publication Date: 2025.11.12 LG ELECTRONICS INC
  • EP4277410B1 patent drawingFigure 1
  • EP4277410B1 patent drawingFigure 2(a)~2(d)
  • EP4277410B1 patent drawingFigure 3

AI summary

Provided are a method by which a first device performs wireless communication, and a device supporting same. The method may comprise the steps of: obtaining a sidelink (SL) discontinuous reception (DRX) configuration including information related to a timer for an active time and information related to a hybrid automatic repeat request (HARQ) round trip time (RTT) timer; starting a timer for the active time; receiving a physical sidelink shared channel (PSSCH) and first sidelink control information (SCI) for scheduling of a second SCI from a second device through a physical sidelink control channel (PSCCH) on the basis of a first SL resource; and receiving the second SCI and data from the second device through the PSSCH on the basis of the first SL resource. Here, the first device may not monitor retransmission of data from the second device in a time domain between the first SL resource and the second SL resource on the basis of the fact that resource allocation information for the second SL resource is included in the first SCI, and the HARQ RTT timer included in the SL DRX configuration may be started by the first device on the basis of the fact that the resource allocation information for the second SL resource is not included in the first SCI.