D2D Frame Number Synchronization for Low-Power UE Communication

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Solution Overview

Problem

Existing Device-to-Device (D2D) communication systems face challenges in synchronizing frame numbers between user equipment (UE) devices, particularly when they are out of cell coverage, leading to increased power consumption and reduced communication efficiency due to simultaneous transmission and reception operations.

Innovation Solution

A method and apparatus for synchronizing frame numbers between D2D UE devices using D2D synchronization signals, allowing half-duplex and full-duplex devices to adjust timing and allocate resources efficiently, with half-duplex devices alternating transmission and reception, and full-duplex devices performing simultaneous operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If D2D terminals communicate without synchronizing frame numbers, then device complexity is reduced, but communication efficiency deteriorates and power consumption increases

Engineering Contradiction:
Improveframe synchronization complexityVSAvoidcommunication efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements self-service by enabling D2D terminals to autonomously synchronize frame numbers through direct peer-to-peer communication. Each terminal independently determines its frame number based on received synchronization signals from other terminals, without requiring network infrastructure or centralized coordination. This self-organizing mechanism resolves the contradiction by providing efficient communication through simple terminal-side operations.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If D2D terminals continuously monitor for synchronization signals, then synchronization accuracy is improved, but power consumption increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by implementing discontinuous reception (DRX) cycles where terminals alternately monitor and sleep. Terminals wake up at predetermined intervals to check for synchronization signals from other D2D devices, then return to sleep mode when no signals are detected. This periodic monitoring maintains synchronization accuracy while dramatically reducing average power consumption compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

3Object-generated harmful factors

If half-duplex terminals alternate between transmission and reception, then interference is reduced, but synchronization complexity increases

Engineering Contradiction:
ImproveinterferenceVSAvoidsynchronization coordination complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by establishing predetermined transmission-reception patterns before D2D communication begins. Terminals are pre-configured with time-division multiplexing schedules that assign specific time slots for transmission and reception. This preliminary coordination reduces interference by ensuring terminals don't transmit and receive simultaneously, while the pre-established patterns minimize the complexity of real-time synchronization decisions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3723300B1Method and device for synchronizing frame numbers between device-to-device communication supported user devices
Publication Date: 2026.05.20 SAMSUNG ELECTRONICS CO LTD
  • EP3723300B1 patent drawingFigure 1
  • EP3723300B1 patent drawingFigure 2
  • EP3723300B1 patent drawingFigure 3

AI summary

A method of synchronizing device-to-device terminals according to an embodiment of the present specification may comprise the steps of: matching timing synchronization with at least one terminal counterpart; and setting a frame number for device-to-device communication after the timing synchronization matching step.