RFID Read-Write Station Modulation for Spectrum Mask Compliance

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Solution Overview

Problem

RFID systems face challenges in operating with maximum transmission power while adhering to varying regional radio regulations, as existing methods require significant hardware changes or are not easily adaptable within the tolerance ranges of technical standards.

Innovation Solution

The method involves varying at least one modulation parameter, such as modulation rate, duration, or degree, at defined intervals to distribute peak values across multiple frequencies, ensuring that the averaged transmission frequency spectrum complies with the permissible spectrum mask, allowing for maximum transmission power usage while adhering to regional regulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If transmission power is increased to maximum level, then communication range and reliability are improved, but the transmission frequency spectrum exceeds the permissible spectrum mask

Engineering Contradiction:
Improvetransmission powerVSAvoidfrequency spectrum emission
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by varying modulation parameters at defined time intervals. The modulation rate, duration, or degree is changed periodically within tolerance limits, causing peak values in the frequency spectrum to be distributed across multiple frequencies rather than concentrated at one frequency, thereby complying with the spectrum mask while maintaining maximum transmission power

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting modulation parameters (modulation rate, modulation duration, or modulation degree) within the tolerance ranges specified by technical standards. These parameter variations cause the transmission frequency spectrum to shift and distribute peak values across different frequencies, allowing maximum transmission power to be used without exceeding the spectrum mask

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If hardware modifications are made to comply with spectrum mask, then frequency spectrum emission is controlled, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvefrequency spectrum emissionVSAvoidhardware complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces hardware modifications with software-based control of modulation parameters. Instead of modifying the physical hardware to control frequency spectrum emission, the invention uses software to dynamically adjust modulation parameters (rate, duration, or degree) within standard tolerance ranges, achieving spectrum mask compliance through intelligent parameter variation rather than hardware changes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates multiple copies of the transmission signal with different modulation parameter settings by varying parameters within tolerance limits. These parameter variations generate equivalent communication效果 distributed across different frequency configurations, allowing compliance with spectrum mask without hardware changes

Inventive Principle:
Principle #26Copying

3Reliability

If existing modulation parameters are used, then communication reliability is maintained, but transmission frequency spectrum exceeds spectrum mask

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidfrequency spectrum emission
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent transforms static modulation parameters into dynamic parameters that vary within defined tolerance ranges. By making the modulation rate, duration, or degree variable rather than fixed, the system maintains communication reliability (as variations stay within standard tolerances) while distributing frequency spectrum peak values across multiple frequencies to comply with the spectrum mask

Inventive Principle:
Principle #15Dynamics

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 enables RFID systems to operate with maximum transmission power while staying within the permissible spectrum mask, reducing the need for hardware changes and being easily implementable through software adjustments, thus optimizing the transmission frequency spectrum.

Implementation Method 1

The task of the antenna of an RFID system is to transmit the energy generated by the read/write station to the transponder or transponders and to transmit data signals to the transponder or transponders

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

RFID systems often use what is known as amplitude modulation, also known as 'amplitude shift keying' (ASK), to send data to a transponder. However, phase-modulated and frequency-modulated systems also belong to the state of the art.

Methodology Applied
Scientific EffectAmplitude modulation: Phase Modulation

Implementation Method 3

The modulation of the carrier frequency results in a transmission frequency spectrum with a number of different frequencies, in which the frequencies contained in the spectrum and the extent to which these frequencies are present in the spectrum depend on the type of signal coding. The cause of the transmission frequency spectrum are harmonic oscillations that arise from the modulation.

Methodology Applied
Scientific EffectHarmonic oscillation: Harmonic Oscillator

Data Source

PatentEP2012251B1Method for optimising the transmitting frequency spectrum of an RFID read-write station
Publication Date: 2011.01.05 FEIG ELECTRONIC GMBH
  • EP2012251B1 patent drawingFigure 1
  • EP2012251B1 patent drawingFigure 2~3
  • EP2012251B1 patent drawingFigure 4~5

AI summary

The method involves performing average determination for determining a transmission frequency spectrum, and varying a modulation parameter, influencing the transmission frequency spectrum, in temporal distances. The modulation parameter is varied within tolerance limits of respective technical standard. A modulation frequency and/or modulation period and/or modulation position and/or modulation factor is varied as the modulation parameter. The modulation parameter is adjusted after a time which is larger than a time constant of the average determination.