Sidelink DRX Alignment for Power Saving

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Solution Overview

Problem

Current wireless communication systems do not implement DRX (Discontinuous Reception) on the sidelink for power saving, particularly for UEs in V2X or public safety applications, leading to increased power consumption and reduced battery life.

Innovation Solution

Implementing DRX specifically for sidelink communications in wireless communication systems, allowing battery-based UEs to conserve power by aligning the sidelink DRX cycles with the Uu interface DRX cycles, both in-coverage and out-of-coverage scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If DRX is implemented on the sidelink for battery-based UEs, then power consumption is reduced and battery life is extended, but communication reliability and responsiveness may deteriorate due to discontinuous reception

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

Solution Approach 1:

The patent implements periodic DRX cycles on the sidelink where UEs alternately enter active and inactive states. During active periods, UEs monitor and transmit sidelink signals; during inactive periods, UEs conserve power by suspending reception. This periodic operation reduces average power consumption while maintaining communication capability through scheduled wake-up intervals.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies DRX alignment mechanisms where UEs pre-coordinate their active periods with communication partners and the network. By preliminarily synchronizing DRX cycles through alignment offsets and reference signals, the system ensures that UEs are awake and ready to communicate at predetermined times, preventing data loss while maximizing power-saving opportunities.

Inventive Principle:
Principle #10Preliminary action

2Loss of energy

If sidelink DRX cycles are aligned with Uu interface DRX cycles, then power saving efficiency is improved through coordinated sleep periods, but system complexity increases due to alignment coordination requirements

Engineering Contradiction:
Improvepower saving efficiencyVSAvoidalignment coordination complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the DRX operations of the sidelink and Uu interface by aligning their active and inactive periods. UEs coordinate to synchronize their DRX cycles such that sidelink and downlink receptions occur during the same active periods, allowing the UE to wake up once for both interfaces rather than separately. This consolidation improves power saving efficiency by reducing the number of wake-up events while managing complexity through unified DRX configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback mechanisms where UEs report their DRX configuration and alignment status to the network. The gNB uses this feedback to adjust DRX parameters and alignment offsets, ensuring optimal synchronization between sidelink and Uu interface DRX cycles. This closed-loop control enables dynamic adaptation to changing traffic conditions while maintaining alignment, balancing power saving benefits with coordination complexity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4496426A1DRX alignment for the sidelink
Publication Date: 2025.01.22 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4496426A1 patent drawingFigure 1(a)~1(b)
  • EP4496426A1 patent drawingFigure 2
  • EP4496426A1 patent drawingFigure 3

AI summary

Embodiments provide a transceiver of a wireless communication system, wherein the transceiver is configured to operate in a sidelink in-coverage, out of coverage or partial coverage scenario, in which resources for a sidelink communication over a sidelink are preconfigured by the wireless communication system or allocated or scheduled autonomously by the transceiver, wherein the transceiver is configured to receive, in the sidelink in-coverage, out of coverage or partial coverage scenario, sidelink signals using a discontinuous reception, DRX, mode of operation, wherein at least one parameter of the discontinuous reception, DRX, mode of operation depends on at least one operating parameter of the transceiver.