Wireless Device Subslot Timing for Microwave Interference

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Solution Overview

Problem

Existing wireless communication devices face reduced communication distance and inefficient transmission due to unwanted radiation from microwave ovens, requiring synchronization with the commercial power supply and accurate recognition of the oven's operation state, which is not always feasible.

Innovation Solution

A wireless communication device that segments transmission data into subslots and transmits them during the oscillator stopping time of the microwave oven's magnetron, avoiding interference by aligning data transmission with the zero cross point of the commercial power supply without needing to synchronize with it or accurately recognize the oven's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If countermeasure communication is constantly performed to remain unobstructed, then communication reliability is improved, but effective transmission rate decreases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoideffective transmission rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The wireless communication device dynamically adjusts its communication strategy based on detected microwave oven operation states. When microwave operation is detected, the device switches to countermeasure communication mode; when not detected, it uses normal communication mode. This dynamic adaptation resolves the contradiction by maintaining reliability only when necessary, thereby preserving transmission rate during normal conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The device incorporates a detection unit that continuously monitors for microwave oven operation and provides feedback to the control unit. This feedback mechanism enables the system to intelligently switch between communication modes, ensuring reliability during microwave operation while maintaining high transmission rates during normal operation, thus resolving the contradiction between reliability and transmission rate.

Inventive Principle:
Principle #23Feedback

2Reliability

If zero cross point detection circuit is added to detect microwave operation timing, then communication during microwave operation is improved, but device complexity increases

Engineering Contradiction:
Improvecommunication during microwave operationVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection unit leverages the existing commercial power supply connection that already powers the wireless communication device. By using the same power supply lines for both operation and detection purposes, the system achieves microwave operation detection without adding separate detection circuits, thus improving communication during microwave operation while avoiding increased device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The power supply circuit serves dual functions: providing operational power to the device and enabling detection of microwave oven operation through voltage fluctuation monitoring. This multi-functionality resolves the contradiction by achieving detection capability without adding dedicated detection hardware, maintaining simplicity while improving communication reliability during microwave operation.

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

3Ease of operation

If communication is performed without zero cross point synchronization, then ease of operation is improved, but communication distance is reduced due to unwanted radiation

Engineering Contradiction:
Improveoperation simplicityVSAvoidunwanted radiation interference
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and utilizes the voltage fluctuation signal from the existing power supply connection to detect microwave operation timing. This extracted information enables the system to identify when the magnetron is not operating (zero cross points) without requiring synchronization circuits, thereby maintaining ease of operation while avoiding unwanted radiation interference during data transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detection unit acts as an intermediary that translates power supply voltage fluctuations into actionable information about microwave operation states. This intermediary mechanism enables the system to indirectly detect magnetron operation timing without direct synchronization, maintaining operational simplicity while avoiding communication during periods of unwanted radiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Duration of action of moving object

If data is transmitted during magnetron oscillation periods, then transmission continuity is improved, but communication quality deteriorates due to unwanted radiation

Engineering Contradiction:
Improvetransmission continuityVSAvoidcommunication quality
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The system transmits data in periodic intervals synchronized with the detected microwave operation cycles. By identifying periodic patterns in power supply voltage fluctuations corresponding to magnetron operation, the device transmits data during non-oscillation periods (zero cross points) while remaining silent during oscillation periods, thus maintaining transmission continuity over time while ensuring communication quality during each transmission window.

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

Enables stable and efficient data transmission by avoiding unwanted radiation, maintaining communication integrity even when the oven is in operation, without relying on zero cross point synchronization or power supply recognition.

Implementation Method 1

The magnetron of a microwave oven oscillates in the vicinity of a frequency of 2.45 GHz, and emits unwanted radiant waves to an ambient environment.

Methodology Applied
Scientific EffectMagnetron oscillation:

Implementation Method 2

The voltage of the microwave oven periodically passes through the point of the voltage 0 V (zero cross point), and oscillation of the magnetron is temporarily stopped in the vicinity of the zero cross point.

Methodology Applied
Scientific EffectZero cross point effect:

Data Source

PatentEP3399682B1Wireless communication device
Publication Date: 2019.08.14 PANASONIC HOLDINGS CORP
  • EP3399682B1 patent drawingFigure 1
  • EP3399682B1 patent drawingFigure 2
  • EP3399682B1 patent drawingFigure 3

AI summary

The present invention relates to a wireless communication device (1) for avoiding an influence of an electric oven operating with a commercial power supply, the wireless communication device (1) comprising:a transmission data generator (6) for generating a transmission data; a modulator (3) for generating modulated signal according to the transmission signal, the transmission comprising a plurality of slots generated by the transmission data generator (6); a high frequency processor (2) for converting the modulated signal to a high frequency signal and for converting a received high frequency signal to a modulated signal; demodulator (4) for demodulating the received modulated signal; a data analyzer (7) for analyzing the demodulated signal; a controller (5) for controlling the modulator (3), the demodulator (4) and the data analyzer (7); and an antenna (8) for transmitting and receiving the high frequency signal, the transmission data generator (6) being configured to generate a plurality of slots, each of the plurality of slots including a predetermined number of subslots, after dividing the transmission data into the plurality of subslots, a sequence of the subslots included in each of the plurality of slots is constant, and the time length T2 of each of the plurality of slots is T2=T0/(2 + T1) or T2=T0/(2 - T1), where T1 is a time length of each of the subslots and the T0 is a period of the commercial AC power supply.