Base Station Time Synchronisation via Mobile Terminal Mediation

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Solution Overview

Problem

In mobile communications networks, especially in indoor environments, small cells often fail to achieve accurate timing phase synchronization due to the limitations of DSL backhaul technology and the lack of overlap between coverage areas, leading to potential interference and instability in handover processes.

Innovation Solution

A method where a mobile terminal receives and stores synchronization data from a first base station and transmits it to a second base station when it moves out of the first base station's coverage area, allowing the second base station to derive a new reference time and synchronize itself, even if the areas do not overlap, with a predetermined fraction of the time difference used to adjust the synchronization data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If base stations rely on DSL backhaul for synchronization, then deployment flexibility and ease of installation are improved, but timing phase synchronization accuracy deteriorates

Engineering Contradiction:
Improvedeployment flexibilityVSAvoidtiming phase synchronization accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces mobile terminals as intermediary carriers to transmit synchronization data between base stations. Instead of relying on the inaccurate DSL backhaul for synchronization, base stations use mobile terminals that have received accurate timing information from GPS or other synchronization sources as mediators to propagate synchronization data across the network, thereby achieving accurate timing phase synchronization while maintaining DSL backhaul deployment flexibility

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary synchronization by having base stations pre-acquire synchronization data from GPS or other external synchronization sources before actual operation. This preliminary action ensures that when base stations communicate with mobile terminals, they already possess accurate timing information, allowing them to maintain precise timing phase synchronization even while using DSL backhaul for data transmission

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If base stations operate in isolated coverage areas without overlap, then network coverage flexibility is improved, but synchronization reliability deteriorates

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

Solution Approach 1:

The patent uses mobile terminals as mediators to bridge synchronization between isolated base stations. When a mobile terminal moves between coverage areas of isolated base stations, it carries synchronization data from one base station to another, enabling synchronization propagation even when base stations have no direct communication path or overlapping coverage, thus maintaining synchronization reliability while allowing isolated coverage deployment

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent ensures continuous synchronization propagation through mobile terminals that continuously carry and update synchronization data as they move between base stations. This continuous action of synchronization data transmission via mobile terminals maintains synchronization reliability across the network even when base stations operate in isolated coverage areas without direct overlap

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If base stations continuously update synchronization data, then synchronization accuracy is improved, but network stability deteriorates due to frequent changes

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidnetwork stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent implements feedback mechanisms where base stations monitor the quality and source of received synchronization data from mobile terminals. Before applying synchronization updates, base stations evaluate whether the incoming data improves upon existing synchronization accuracy. This feedback-based selective updating ensures synchronization accuracy improves only when genuinely better data is received, while rejecting unnecessary or degrading updates, thus maintaining network stability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies partial updating by selectively applying only the necessary portion of synchronization updates from mobile terminals. Rather than blindly accepting all incoming synchronization data, base stations apply updates only when they represent genuine improvements in synchronization accuracy, performing partial actions rather than complete updates, thereby improving accuracy while avoiding excessive changes that would destabilize the network

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3257169B1Base station time synchronisation in a wireless network
Publication Date: 2018.11.28 BRITISH TELECOM PLC
  • EP3257169B1 patent drawingFigure 1
  • EP3257169B1 patent drawingFigure 2
  • EP3257169B1 patent drawingFigure 3

AI summary

The operation of base stations (300a, 300b) in a wireless network whose areas of coverage do not overlap are synchronised by taking timing values from mobile units (400) that travel from one area of coverage to another. A base station (300b) receiving a timing value from a mobile unit entering its area of coverage adapts (10) its timing value and that of any mobile units in its coverage area, including the newly-arrived mobile unit, to a become a value intermediate between its existing timing value and that indicated by the mobile unit. The use of an intermediate value instability in the system that might result from an inability of the base stations to communicate directly with each other in real time.