Sidelink DRX Resource Reservation for NR V2X HARQ Retransmission

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing resource allocation and retransmission in sidelink (SL) communication, particularly in vehicle-to-everything (V2X) scenarios, due to the overhead caused by increasing data traffic and the need for enhanced mobile broadband communication.

Innovation Solution

A method for performing resource selection and retransmission in SL discontinuous reception (DRX) based on a SL DRX configuration, utilizing hybrid automatic repeat request (HARQ) feedback for efficient resource utilization and retransmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If SL DRX configuration is used to reduce power consumption and overhead, then energy efficiency is improved, but resource allocation complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidresource allocation complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The transmitting UE performs resource selection and reserves resources in advance within the active time window before the receiving UE enters sleep mode. This preliminary resource allocation ensures that retransmissions can occur without requiring the receiving UE to remain active, thereby reducing power consumption while maintaining manageable resource allocation complexity through advance planning

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts resource allocation based on DRX active time windows. The transmitting UE identifies and selects resources that fall within the receiving UE's active time, creating a dynamic resource allocation scheme that adapts to the receiving UE's sleep-wake pattern. This dynamic approach optimizes energy efficiency while keeping resource management tractable through time-window-based constraints

Inventive Principle:
Principle #15Dynamics

2Reliability

If resource selection is performed within active time only, then retransmission reliability is improved, but resource availability decreases

Engineering Contradiction:
Improveretransmission reliabilityVSAvoidresource availability
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system introduces a time dimension constraint by limiting resource selection to active time windows. Instead of selecting from all available resources in time-frequency space, the transmitting UE selects resources that satisfy the additional temporal constraint of falling within the receiving UE's active time. This dimensional constraint ensures retransmission reliability while the system compensates for reduced resource availability by optimizing selection within the constrained space and potentially using multiple DRX cycles

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

3Reliability

If DRX active time is extended to accommodate retransmissions, then retransmission success rate is improved, but latency increases

Engineering Contradiction:
Improveretransmission success rateVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The transmitting UE performs preliminary resource selection within the active time window and reserves these resources in advance. By selecting and reserving retransmission resources before the DRX cycle ends, the system ensures that retransmissions can occur immediately when needed without extending the active time, thereby maintaining low latency while achieving high retransmission success rates

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transmitting UE autonomously identifies suitable retransmission resources within the active time window and performs resource reservation without requiring network intervention or extending the receiving UE's active time. This self-service approach allows the system to achieve reliable retransmissions through intelligent resource selection and reservation, maintaining both low latency and high success rates

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4192173B1Method and device for performing SL DRX operation in NR v2x
Publication Date: 2026.01.07 LG ELECTRONICS INC
  • EP4192173B1 patent drawingFigure 1
  • EP4192173B1 patent drawingFigure 2(a)~2(d)
  • EP4192173B1 patent drawingFigure 3

AI summary

Disclosed is a method for operating a first device (100) in a wireless communication system. The method may comprise the steps in which: resource selection for a resource included in an active time of a sidelink (SL) discontinuous reception (DRX) configuration is performed on the basis of a second device (200) performing SL communication on the basis of the SL DRX configuration; and information related to the resource selected on the basis of the resource selection is transmitted to the second device (200).