D2D Synchronization Source Selection Using Signal Power Thresholds

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Solution Overview

Problem

Device-to-device (D2D) synchronization in wireless communication systems faces challenges such as timing misalignment and confusion when multiple synchronization sources are present, particularly for UEs outside the network coverage, leading to unreliable network timing and potential communication disruptions.

Innovation Solution

A D2D synchronization method that involves detecting synchronization signals from multiple sources, selecting a synchronization source based on power thresholds and relative distance, and determining whether to forward timing information or act as an independent synchronization source, ensuring reliable network timing alignment and minimizing timing confusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a D2D device receives multiple synchronization signals simultaneously, then the device can potentially synchronize with different sources, but timing misalignment and confusion occur when the wrong device is selected

Engineering Contradiction:
Improvesynchronization source selection flexibilityVSAvoidtiming alignment reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the parameter of synchronization signal power level to determine the selection criterion. The UE compares the power levels of received synchronization signals from different sources and selects the source with the highest power, thereby resolving the timing alignment reliability issue while maintaining selection flexibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different selection criteria based on the local situation - whether the UE is in network coverage or out of coverage. When in coverage, the UE prioritizes network synchronization signals; when out of coverage, it selects from peer device signals, thus resolving the contradiction between adaptability and reliability

Inventive Principle:
Principle #3Local quality

2Ease of operation

If a D2D device blindly searches for another device in asynchronous communication, then device autonomy is improved, but timing confusion increases due to lack of network coordination

Engineering Contradiction:
Improvedevice autonomyVSAvoidtiming reference consistency
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary action by having the UE perform power level comparison and synchronization source selection before establishing D2D communication. This preliminary evaluation ensures that the device autonomously selects the most reliable timing reference, maintaining both device autonomy and timing reference consistency

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If D2D UEs outside network coverage select peer devices as synchronization sources, then communication range is extended, but timing confusion increases due to multiple different timing references

Engineering Contradiction:
Improvecommunication coverage areaVSAvoidtiming reference reliability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent uses power level as a selection parameter to choose the best peer device synchronization source. By selecting the peer device with the strongest signal, the UE extends communication range to out-of-coverage areas while minimizing timing confusion through consistent selection criteria

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback mechanisms where UEs monitor the quality and consistency of received synchronization signals. This feedback allows the system to adaptively maintain timing reference reliability even when operating outside network coverage with multiple potential sources

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2900022B1Device to device synchronization method applicable to user equipment and user equipment using the same
Publication Date: 2018.12.19 IND TECH RES INST
  • EP2900022B1 patent drawingFigure 1
  • EP2900022B1 patent drawingFigure 2
  • EP2900022B1 patent drawingFigure 3A

AI summary

The present disclosure provides a device to device (D2D) synchronization method that is applicable to a user equipment and a user equipment (UE) using the same method. In one of the exemplary embodiments, the D2D synchronization method includes receiving detected signals from a receiver, obtaining from the detected signals a first signal having a first timing information and a second signal having a second timing information, determining whether to forward the first timing information or the second timing information based on an upper bound power restriction of the first signal and the second signal and a power difference between the first signal and the second signal, and determining whether to transmit a third timing information that is inherent of the UE based on whether the first signal and the second signal are below power thresholds.