Sidelink Relay DRX Alignment Through gNB Assistance Signaling

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Solution Overview

Problem

The challenge in wireless communication systems, particularly in sidelink relay operations, is the misalignment of Discontinuous Reception (DRX) configurations between the Uu interface and sidelink interface, which can lead to difficulties in maintaining the quality of service for remote UEs that rely on relay UEs for connection to the base station.

Innovation Solution

A method is proposed where a relay UE reports assistance information for DRX configuration to the gNB, allowing the gNB to configure both Uu DRX and sidelink DRX for the remote UE, ensuring alignment and maintaining QoS, regardless of the relay UE's resource allocation mode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the relay UE autonomously determines SL DRX configuration or operates in mode 2, then the relay UE can independently manage sidelink resources, but the alignment between Uu DRX and SL DRX configurations cannot be ensured

Engineering Contradiction:
Improveautonomous DRX configurationVSAvoidQoS alignment
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The gNB acts as an intermediary that receives assistance information from the relay UE and uses it to determine the SL DRX configuration. This mediator approach ensures that the network has final authority over DRX alignment while still incorporating the relay UE's operational insights, resolving the contradiction between autonomous operation and configuration alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The relay UE provides assistance information (feedback) about its resource allocation mode and operational characteristics to the gNB. This feedback loop enables the gNB to make informed decisions about SL DRX configuration that are aligned with both network requirements and relay UE capabilities, ensuring QoS consistency across Uu and SL interfaces.

Inventive Principle:
Principle #23Feedback

2Reliability

If the gNB configures SL DRX based on relay UE assistance information, then DRX alignment between Uu and SL interfaces is achieved, but additional signaling overhead is introduced

Engineering Contradiction:
ImproveDRX configuration alignmentVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The relay UE prepares and transmits assistance information in advance before the gNB needs to configure SL DRX. This preliminary action allows the gNB to quickly determine the optimal SL DRX configuration without extensive back-and-forth signaling, reducing overall signaling overhead while ensuring accurate DRX alignment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The assistance information contains key parameters about the relay UE's operational mode and resource allocation. By changing and transmitting only these essential parameters rather than complete configuration details, the signaling overhead is minimized while still providing sufficient information for the gNB to achieve DRX alignment.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the relay UE operates in mode 1 with network-controlled resource allocation, then resource allocation is centralized and controlled, but the relay UE cannot independently adapt SL DRX to local conditions

Engineering Contradiction:
Improvecentralized controlVSAvoidlocal adaptation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The solution merges the advantages of both centralized control and local adaptation by combining network-controlled resource allocation (mode 1) with relay UE-provided assistance information about local conditions. This hybrid approach allows the gNB to maintain centralized control while incorporating local adaptation capabilities through the assistance information feedback mechanism.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4250861B1DRX in sidelink communication relay
Publication Date: 2025.07.23 LG ELECTRONICS INC
  • EP4250861B1 patent drawingFigure 1
  • EP4250861B1 patent drawingFigure 2
  • EP4250861B1 patent drawingFigure 3

AI summary

A method of relaying, by a first user equipment (UE), sidelink communication between a base station (BS) and a second UE in a wireless communication system, and an apparatus therefor are disclosed. The first UE receives assistance information for determining a sidelink discontinuous reception (DRX) configuration from the second UE, transmits the assistance information to the BS regardless of a resource allocation mode of the first UE, receives Uu link DRX configuration information and sidelink DRX configuration information from the BS, and transmits the sidelink DRX configuration information to the second UE.