DAS Fault Location via Frequency Difference Amplitude Spectrum

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Solution Overview

Problem

Current distributed antenna systems (DAS) lack monitoring capabilities, making it impossible to accurately locate faulty nodes when faults occur, as existing systems cannot detect or analyze issues in real-time.

Innovation Solution

An apparatus and fault location system that generates and analyzes frequency difference and amplitude spectrum graphs by sending detection signals through the DAS, using signal processing and analysis modules to identify node locations and fault sources by superposing and converting echo signals, enabling precise fault location within the DAS.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If no monitoring system is implemented in DAS, then the system structure remains simple and cost-effective, but fault detection capability is lost and faulty nodes cannot be located

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The DAS uses its own transmission lines to transmit both power and detection signals, and utilizes the existing cable infrastructure to carry monitoring information back to the main circuit. The system monitors itself through the same physical medium it uses for normal operation, eliminating the need for separate monitoring hardware and enabling fault detection without adding external complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The transmission lines in the DAS serve multiple functions: they carry power to remote units, transmit data signals, and simultaneously serve as the medium for fault detection by carrying echo signals. This multi-functionality allows the system to gain monitoring capabilities without requiring dedicated monitoring infrastructure, thus improving reliability while maintaining simplicity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If traditional fault detection methods are used in DAS, then some fault detection is possible, but accurate location of faulty nodes cannot be achieved

Engineering Contradiction:
Improvefault location precisionVSAvoidfault detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system uses signal reflection (analogous to vibration echo) to detect faults. When a detection signal encounters a fault or discontinuity in the transmission line, it reflects back as an echo signal. By analyzing the characteristics of this reflected signal, the system can precisely locate the fault position and identify the type of fault without requiring complex measurement equipment.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The system implements a feedback mechanism where echo signals reflected from faults are captured and analyzed to determine fault location and characteristics. This feedback loop enables continuous monitoring and precise fault identification by comparing the reflected signals against expected patterns, allowing accurate measurement of fault positions while maintaining relatively simple detection procedures.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate identification and location of faulty nodes in DAS, improving fault detection and maintenance efficiency by providing a graphical representation of node amplitudes and locations, thus facilitating swift issue resolution.

Implementation Method 1

receive an echo signal returned by the branch circuit, where the echo signal is a signal obtained after the detection signal is reflected by the M coupling nodes on the main circuit and the N antenna nodes and the K coupling nodes on the branch circuit

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3355605B1Apparatus for obtaining frequency difference amplitude spectrogram, fault location system and antenna system
Publication Date: 2021.06.30 HUAWEI TECH CO LTD
  • EP3355605B1 patent drawingFigure 1~2
  • EP3355605B1 patent drawingFigure 3
  • EP3355605B1 patent drawingFigure 4

AI summary

This application relates to the communications field, and provides an apparatus for obtaining a frequency difference and amplitude spectrum graph, a fault location system, and an antenna system, which can be used to locate a faulty node in a DAS, thereby accurately locating a fault source in the DAS. The apparatus includes a signal generation module that generates and sends a detection signal. For each of at least one branch circuit in the DAS, a signal transmission module connected to the signal generation module sends the detection signal to the branch circuit through an input end of the DAS, and sends a signal processing module the received detection signal and an echo signal returned by the branch circuit, where the echo signal is a signal obtained after the detection signal is reflected by nodes that are on a main circuit and the branch circuit in the DAS and through which the detection signal passes in sequence. The signal processing module superposes the received detection signal and echo signal, and sends a superposed signal to a signal analysis module connected to the signal processing module. The signal analysis module performs spectrum conversion on the received superposed signal, to obtain a frequency difference and amplitude spectrum graph, where the frequency difference and amplitude spectrum graph indicates a correspondence between a location of each node on the main circuit and the branch circuit and an amplitude of the echo signal corresponding to the node.