Clustering Apparatus for Dynamic Master Selection in Timing Synchronization

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Solution Overview

Problem

Existing methods for synchronizing phase and frequency in small cells using network assisted global navigation satellite systems (AGNSS) and timing packets face challenges such as variable signal intensity, packet delay variation, and limited scalability due to fixed master-slave structures, which affect accuracy and synchronization quality, especially in indoor environments with potential line-of-sight issues and network congestion.

Innovation Solution

A clustering apparatus and method that determines a best master with high quality based on a neighbor list provided by a server, allowing for dynamic master-slave relationships and balanced load distribution by applying weights to master and network quality levels, enabling autonomous cluster organization and reducing server load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed master-slave structure is used for synchronization, then the system is simple to implement, but the number of slaves is limited and packet delay variation increases

Engineering Contradiction:
Improvesynchronization system structureVSAvoidnumber of slaves
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic master selection where slaves can switch between different masters based on real-time quality metrics. Instead of a fixed master-slave assignment, the system continuously evaluates master quality and allows slaves to reassign themselves, transforming the static structure into a dynamic one that adapts to changing network conditions and supports unlimited slave connections.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the synchronization system into multiple independent master nodes that can each serve different groups of slaves. By dividing the monolithic master role into multiple specialized masters with different quality characteristics, the system can handle more slaves simultaneously and reduce the packet delay variation that occurs when all slaves converge on a single master.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If multiple slaves converge on one master, then centralization is achieved, but packet delay variation increases due to network congestion

Engineering Contradiction:
Improvecentralized controlVSAvoidphase and frequency synchronization quality
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies local quality by allowing different masters to serve different geographic or network regions with locally optimized synchronization quality. Each master maintains independent synchronization state and serves its local slave population, preventing network congestion from affecting all slaves uniformly. This distributes the synchronization load while maintaining centralized control within each local cluster.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces quality metrics and selection algorithms as intermediaries between slaves and masters. Instead of direct arbitrary assignment, slaves use quality measurements (packet delay variation, signal strength, etc.) as intermediaries to select the most appropriate master, thereby distributing load to masters that can handle them optimally and reducing overall network congestion impact on synchronization quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single master handles all slaves, then system结构简单ity is maintained, but the distance over network increases making synchronization difficult

Engineering Contradiction:
Improvemaster-slave structureVSAvoidnetwork distance
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent adds a spatial dimension to the master-slave architecture by distributing multiple masters across different network locations. Instead of all slaves connecting to a single centralized master, slaves can connect to geographically or network-topologically closer masters, reducing the effective network distance and improving synchronization performance while maintaining overall system structural simplicity.

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

4Adaptability or versatility

If AGNSS signal intensity is low due to environment, then outdoor coverage is achieved, but synchronization accuracy decreases

Engineering Contradiction:
Improvecoverage areaVSAvoidsynchronized time accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent merges AGNSS-based synchronization with timing packet-based synchronization into a hybrid system. When AGNSS signal intensity is low or unavailable (indoor environments), the system automatically falls back to or combines with timing packet synchronization from local masters, thereby maintaining both wide coverage capability and high synchronization accuracy across diverse environments.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic parameter changes by adjusting the weight or priority of different synchronization sources (AGNSS vs. timing packets) based on signal conditions. When AGNSS signal quality deteriorates due to environmental factors, the system changes parameters to rely more heavily on timing packet synchronization, maintaining accuracy while preserving outdoor coverage capability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2710761B1Clustering apparatus and method for controlling timing
Publication Date: 2019.02.27 ERICSSON LG CO LTD
  • EP2710761B1 patent drawingFigure 1
  • EP2710761B1 patent drawingFigure 2
  • EP2710761B1 patent drawingFigure 3

AI summary

A clustering apparatus and method that can be used when synchronizing phase and frequency using a hybrid system of network assisted global navigation satellite system (AGNSS) and timing packet. A clustering apparatus for controlling timing is to determine a best master having a higher master-slave quality level among potential masters that can provide a timing packet based on a neighbor list provided by a server. The clustering apparatus organizes a cluster having linkability between the best master and at least one slave. The clustering apparatus performs synchronization between the best master and said at least one slave for each cluster.