Quartz Error Compensation in Smart Meter Radio Links

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Solution Overview

Problem

Intelligent consumption meters face challenges in data transmission due to interference, precise time synchronization issues, and quartz errors leading to poor transmission quality between consumption meters and data collectors, especially in environments with frequent device usage and building-specific features.

Innovation Solution

The method involves estimating and correcting quartz errors in communication modules using software-based computational models, adjusting parameters like data rate, frequency, and modulation index to synchronize communication, thereby optimizing transmission quality and reducing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If radio transmission is used in ISM or SRD frequency ranges, then general approval for frequency management is obtained, but interference occurs due to frequent use by various technical devices

Engineering Contradiction:
Improvefrequency management approvalVSAvoidinterference
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The data collector measures at least one parameter (bandwidth, data rate, data rate offset, temperature, Δfrequency, modulation index, or reception time) from the received data packet and uses this feedback to determine the quartz error of the second frequency reference device, then adjusts parameters to compensate for the error and improve transmission quality

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes communication parameters (data rate, data rate offset, modulation index) based on the determined quartz error to optimize transmission quality and compensate for frequency reference device inaccuracies

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If simple crystals with low power consumption are used as frequency reference devices, then power consumption is reduced, but crystal defects of 10-100 ppm occur due to manufacturing tolerances, temperature behavior and aging

Engineering Contradiction:
Improvepower consumptionVSAvoidtime synchronization
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system continuously measures transmission parameters and determines the quartz error of the frequency reference device, using this feedback to dynamically adjust communication parameters and compensate for crystal drift over time and temperature

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis by measuring its own transmission parameters and automatically compensates for frequency reference device errors through parameter adjustment, eliminating the need for external calibration

Inventive Principle:
Principle #25Self-service

3Productivity

If data packets are transmitted during very short reference periods, then legal requirements for consumption evaluation are met, but transmission quality is poor due to interference between multiple transmitters and building-specific features

Engineering Contradiction:
Improvemeter reading frequencyVSAvoiddata packet reception
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system adjusts communication parameters (data rate, modulation index) based on the determined quartz error to optimize transmission quality within the constrained reference period, improving the probability of correct reception

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system determines the quartz error and adjusts parameters in advance before critical transmission periods, preparing the communication system to handle the constrained reference period transmissions more effectively

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3549351B1Method for improving the transmission quality between a data collector and a plurality of autonomous measuring units, and communication system
Publication Date: 2021.03.31 DIEHL METERING SYSTEMS GMBH
  • EP3549351B1 patent drawingFigure 1
  • EP3549351B1 patent drawingFigure 2
  • EP3549351B1 patent drawingFigure 3

AI summary

The invention relates to a method for improving the transmission quality between a data collector (3) and a plurality of measuring units, in particular consumption measuring devices (2), in a communication system (1) with preferably bidirectional radio transmission with a first communication module (10), wherein the first communication module (10) is associated with the data collector (3), and two or more second communication modules (17), wherein each second communication module (17) is associated with one measuring unit, wherein the second communication module (17) is provided for sending data to the first communication module (10) by means of radio signals, preferably in the form of at least one radio telegram (4) preferably comprising a plurality of data packet(s), wherein the first communication module (10) is provided for receiving the data from the second communication module (17), wherein the first communication module (10) comprises a first frequency reference device (11), wherein the second communication module (17) comprises a second frequency reference device (18), wherein the radio signals transferred from the second communication module (17) to the first communication module (10) in the data transmission are dependent on the second frequency reference device (18), wherein at least one parameter of the radio signal sent out by the second communication module (17) and received by the first communication module (10), from the parameter group comprising bandwidth, data rate, data rate offset, temperature from the data packet, Δfrequency, modulation index, and/or reception time by the first communication module (10), is measured, an error of the second frequency reference device (18) is estimated on the basis of the parameter measurement values or values derived therefrom, and the frequency of the first frequency reference device (11) and/or at least one parameter in the first communication module (10) from the group comprising data rate, data rate offset, modulation index and frequency shift is adjusted in such a way that the error of the second frequency reference device (18) or the parameter error dependent thereon is reduced or eliminated.