OFDM Data Transmission on Power Lines

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Solution Overview

Problem

Current data transmission methods, particularly in industrial environments, face challenges in ensuring secure and error-resistant data transmission due to amplitude attenuation and interference, especially in powerline transmission systems.

Innovation Solution

The method involves using orthogonal frequency division multiplexing (OFDM) with repeated OFDM symbols and a chirped test signal to determine and adjust the repetition rate based on signal strength, enhancing the signal-to-noise ratio and error resistance by coupling data signals inductively or capacitively through a conductor loop, allowing for simultaneous data and energy transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If OFDM symbols are repeated multiple times to improve signal-to-noise ratio, then data transmission reliability is improved, but transmission time increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies periodic action by repeating OFDM symbols multiple times within a telegram structure. Each symbol is transmitted n times (where n≥2) to accumulate signal energy and improve signal-to-noise ratio through coherent addition at the receiver, while maintaining controlled transmission time through optimized repetition schemes

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the repetition rate parameter dynamically based on signal strength measurements. The receiver determines signal strength and feeds back information to the transmitter, which then adjusts the number of repetitions n accordingly, optimizing the balance between reliability improvement and time consumption

Inventive Principle:
Principle #35Parameter changes

2Reliability

If data transmission security is improved through signal processing, then error resistance is improved, but device complexity increases

Engineering Contradiction:
Improveerror resistanceVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the data transmission process into distinct OFDM symbols that can be independently repeated and processed. Each symbol is treated as a separate unit that can be transmitted multiple times with identical content, allowing for simplified receiver processing through coherent addition without requiring complex joint processing algorithms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where the receiver measures signal strength and communicates this information back to the transmitter. This enables adaptive adjustment of the repetition rate n based on actual channel conditions, optimizing error resistance while avoiding unnecessary complexity from fixed high-repetition schemes

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the same line is used for both data and energy transmission, then resource utilization is improved, but interference increases

Engineering Contradiction:
Improveresource utilizationVSAvoidinterference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses periodic OFDM symbol repetition to create a structured transmission pattern that can be distinguished from irregular power line interference. The periodic nature of repeated symbols allows the receiver to identify and reject impulsive noise that does not follow the same periodic pattern, enabling simultaneous data and energy transmission on the same line

Inventive Principle:
Principle #19Periodic action

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

This approach improves the reliability and security of data transmission by optimizing the repetition rate of OFDM symbols according to transmission medium properties, effectively mitigating interference and ensuring robust communication even in noisy industrial environments.

Implementation Method 1

The coupling device 40, 60 is designed to couple the data signal preferably without contact to the line 3

Methodology Applied
Scientific EffectInductive coupling: Electromagnetic Induction

Implementation Method 2

The coupling device 40, 60 is designed to couple the data signal preferably without contact to the line 3

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2524444B1Method for transmission of data and energy on the same line and corresponding transmission system
Publication Date: 2015.04.01 SEW EURODRIVE GMBH & CO KG
  • EP2524444B1 patent drawingFigure 1
  • EP2524444B1 patent drawingFigure 2

AI summary

The invention relates to a method for data transfer by means of orthogonal frequency multiplexes (OFDM) between a transmitter (10) and a receiver (12) having a data signal, wherein the data signal has a telegram (14) which is constructed from OFDM symbols, wherein the OFDM symbols are transmitted by the transmitter (10) having a repetition rate n times consecutively within the telegram (14) and upon receiving in the receiver (12), the n times consecutively transmitted OFDM symbols are added in phase.