Base Station Frequency Synchronization via Backhaul Accuracy Exchange

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Solution Overview

Problem

In 5G and LTE systems, existing synchronization schemes using GPS signals face challenges in maintaining frequency accuracy due to increased capital and operational costs, and instability in receiving GPS signals indoors, leading to issues with frequency synchronization accuracy.

Innovation Solution

A base station notifies a second base station of its frequency accuracy information, allowing the second base station to synchronize with an adjacent base station having higher frequency accuracy using network listening, thereby ensuring guaranteed frequency accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS synchronization is used, then frequency accuracy is improved, but capital expenditure and operation and maintenance costs increase

Engineering Contradiction:

Improvefrequency accuracyVSAvoidcapital expenditure and operation and maintenance costs

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a backhaul communication network as an intermediary to transmit frequency accuracy information between base stations. Instead of directly using GPS signals at each base station, the system uses a centralized backhaul network to distribute synchronization information, thereby reducing the need for expensive GPS equipment and cable wiring at each site while maintaining frequency accuracy through network-based information exchange.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If GPS signals are received indoors, then synchronization is achieved, but signal stability deteriorates

Engineering Contradiction:

Improvesynchronization achievementVSAvoidsignal stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The backhaul network acts as a mediator that relays frequency accuracy information from base stations with stable GPS reception to base stations located indoors or in GPS-denied environments. This allows indoor base stations to achieve synchronization without directly receiving unstable GPS signals, as they obtain synchronized timing information through the more stable backhaul network infrastructure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If multi-hop synchronization is used, then network adaptability is improved, but frequency accuracy guarantee deteriorates

Engineering Contradiction:

Improvenetwork adaptabilityVSAvoidfrequency accuracy guarantee

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where base stations notify each other of their frequency accuracy information through the backhaul network. In multi-hop synchronization scenarios, base stations can evaluate the frequency accuracy of potential synchronization sources based on this feedback information, allowing them to select the most accurate base station for synchronization even across multiple hops, thereby maintaining frequency accuracy guarantees while preserving network adaptability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12335882B2Base station, communication system, communication method, and non-transitory computer-readable medium

Publication Date: 2025.06.17 NEC CORP

AI summary

A first base station (131) is configured to notify a second base station (132) of frequency accuracy information indicating frequency accuracy of the first base station (131) in a wireless manner or via a backhaul.