Base Station Synchronization via Stratum Selection

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Solution Overview

Problem

In wireless communication systems, especially in LTE networks, small base stations like home evolved NodeBs (HeNBs) often lack GPS synchronization, leading to interference and inefficiencies in synchronization processes, as they may not receive GPS signals or have GPS receivers, necessitating alternative methods for stratum information conveyance and synchronization.

Innovation Solution

A method for self-synchronization of base stations, where synchronization information is received from a second base station with the lowest stratum, and synchronization is achieved by adjusting timing to match the synchronizing base station, using coordinated silence periods to improve signal-to-interference noise ratio (SINR), and conveying information through channels like PDCCH and PDSCH in LTE systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If small base stations use GPS for synchronization, then synchronization accuracy is improved, but device complexity and cost increase due to GPS receiver requirements

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidGPS receiver requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary synchronization mechanism where small base stations receive synchronization information from larger base stations or network nodes rather than directly from GPS. This mediator approach allows indirect synchronization through the network infrastructure, eliminating the need for GPS receivers in small base stations while maintaining synchronization accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables small base stations to perform self-synchronization by automatically selecting synchronization sources and adjusting their timing based on received synchronization information. The base stations autonomously determine their stratum level and synchronize without manual configuration or GPS hardware, making the system self-organizing and adaptable.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If multiple base stations transmit synchronization information simultaneously, then synchronization coverage is improved, but interference increases and signal-to-interference noise ratio deteriorates

Engineering Contradiction:
Improvesynchronization coverageVSAvoidinterference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the synchronization transmission process into distinct time slots or periods, where base stations transmit synchronization information sequentially rather than simultaneously. This time-division approach divides the synchronization coverage task among multiple base stations while preventing interference, allowing each station to transmit during its designated slot.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic transmission schedules where base stations transmit synchronization information at predetermined intervals rather than continuously or simultaneously. This periodic action pattern ensures that synchronization coverage is maintained through repeated transmissions at different times, while the time separation prevents harmful interference between multiple transmitters.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2417809B1Conveying synchronization stratum information
Publication Date: 2016.02.17 QUALCOMM INC
  • EP2417809B1 patent drawingFigure 1
  • EP2417809B1 patent drawingFigure 2
  • EP2417809B1 patent drawingFigure 3

AI summary

A method for self synchronization of a first base station is described. Synchronization information is received from a second base station. The first base station then synchronizes with the second base station using the received synchronization information. Synchronization information may be received from one or more base stations. The second base station may be part of the one or more base stations. A stratum may be determined for each of the one or more base stations. The synchronization information may include a stratum. The second base station may be selected as a synchronizing base station. The second base station may have the lowest stratum.