Femtocell Synchronization via Intermediary Anchors

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Solution Overview

Problem

Low power base stations, such as femto nodes, often face challenges in synchronizing frequency and timing due to poor signal quality from anchor sources like GPS or macrocell base stations, leading to difficulties in maintaining accurate synchronization for wireless communication.

Innovation Solution

A method and apparatus for a low power base station to receive signals from anchor sources, determine signal quality, and adjust its frequency and timing based on weighted averages from multiple sources, advertising its status as an anchor if within a threshold, to ensure synchronization with other base stations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If low power base stations rely on anchor signals from GPS or macrocell base stations for synchronization, then frequency and timing synchronization can be achieved, but signal quality deteriorates in poor network environments

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidsignal quality
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces intermediary femto nodes that act as local synchronization sources for other femto nodes. These intermediary nodes receive anchor signals when available and maintain synchronization, then broadcast their synchronization status to neighboring femto nodes, enabling indirect synchronization in areas where direct anchor signal reception is poor.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the synchronization network into multiple hierarchical levels: anchor sources (GPS/macrocell), primary femto nodes that directly receive anchors, and secondary femto nodes that synchronize to primary nodes. This segmentation allows the system to maintain synchronization throughout the network even when individual nodes cannot directly access anchor signals.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If low power base stations deploy independently without considering network environment, then deployment flexibility increases, but synchronization reliability decreases

Engineering Contradiction:
Improvedeployment flexibilityVSAvoidsynchronization reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms where femto nodes continuously monitor their synchronization status and signal quality, then adjust their behavior accordingly. Nodes that detect poor anchor signal quality can switch to using neighboring femto nodes as synchronization sources, and the network dynamically routes synchronization requests based on current conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent creates a dynamic synchronization architecture where femto nodes can change their synchronization source based on real-time network conditions. Nodes can switch between anchoring to GPS, macrocell signals, or neighboring femto nodes, allowing the system to adapt to changing environmental conditions and maintain reliability regardless of deployment location.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2754330B1Method and apparatus for distributed synchronization in femtocell networks
Publication Date: 2016.08.03 QUALCOMM INC
  • EP2754330B1 patent drawingFigure 1
  • EP2754330B1 patent drawingFigure 2
  • EP2754330B1 patent drawingFigure 3

AI summary

Aspects disclosed herein relate to facilitating synchronizing frequency and/or timing of a wireless network. In an example, with a femto node configured to receive one or more signals from one or more anchor sources, determine that at least one of the one or more signals are received at least at a threshold signal quality, determine whether a difference in a local frequency and/or a local timing is within a threshold difference to a signal frequency and/or a signal timing determined based on the at least one of the one or more signals, and advertise an anchor status where the difference is within the threshold difference.