Electronic Price Label Interference Mitigation via Time-Division Multiplexing
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Solution Overview
Problem
Electronic price label systems and electronic article surveillance systems often interfere with each other when operating in the same frequency band, leading to unreliable operations and potential conflicts in retail environments.
Innovation Solution
The electronic price label system is configured to start transmitting only when the electronic article surveillance system's detection means are in a deactivated state, using passive backscatter radio communication and integrating with the article surveillance system to coordinate transmission states, ensuring no interference occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electronic price label system and electronic article surveillance system operate in the same frequency band simultaneously, then both systems can be deployed in the same retail environment, but interference occurs between the two systems leading to unreliable operations
Solution Approach 1:
The system implements periodic time-division multiplexing where the electronic article surveillance detection means operate during specific time intervals and the electronic price label base station transmits during other intervals. This periodic switching allows both systems to share the same frequency band without simultaneous operation, eliminating interference while maintaining adaptability.
Solution Approach 2:
The system dynamically adjusts the operational state of the detection means based on the transmission state of the base station. When the base station is transmitting, the detection means are switched off; when the base station is not transmitting, the detection means are switched on. This dynamic coordination allows both systems to function reliably in the same frequency band.
2Reliability
If the detection means are kept continuously activated to ensure reliable tag detection, then theft prevention is effective, but interference with price label transmissions occurs
Solution Approach 1:
The detection means operate periodically rather than continuously, being activated only during time intervals when the base station is not transmitting. This periodic operation maintains effective theft prevention coverage while eliminating continuous interference with price label communications.
Solution Approach 2:
The harmful interference effect is extracted and eliminated by switching off the detection means during base station transmission intervals. This removes the conflicting signal source while preserving the detection function during safe time windows.
3Reliability
If the base station transmits continuously to ensure accurate price updates, then price information reliability is maintained, but interference with article surveillance detection occurs
Solution Approach 1:
The base station transmits periodically in time-division slots rather than continuously, updating price information at regular intervals. This periodic transmission maintains price accuracy while creating interference-free windows for surveillance detection operations.
Solution Approach 2:
The base station dynamically adjusts its transmission schedule to coordinate with the surveillance system's detection intervals, transmitting only when detection means are inactive. This dynamic time coordination ensures both price update reliability and surveillance effectiveness without mutual interference.
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 solution allows both systems to operate reliably in the same environment without causing interference, even when using the same frequency band, by synchronizing transmissions with the state of the electronic article surveillance system, thus preventing conflicts and ensuring accurate price updates and tag detection.
Implementation Method 1
the price display unit only reflects the radio transmission of the base station at a given moment of time and in a given way. The price display unit can change the reflectance of its own antenna
Implementation Method 2
The electronic price label system is configured to start transmitting transmissions only when detection means of the electronic article surveillance system are in deactivated state
Data Source
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AI summary
An arrangement, system and method for reducing the effect of interference at radio frequencies in an electronic price label system. The arrangement comprises an electronic price label system, which comprises a base station (102) equipped with at least a radio transmitter and a radio receiver as well as a set of electronic price labels (100, 300) that receive and reflect back radio signals from the base station (102). The electronic price label system is connected to an electronic article surveillance system (110) which comprises detection means (112) which are able to detect electronic article surveillance tags, and which electronic article surveillance system further comprises activation means (114) for changing a state of the detection means (112) between an activated-state and a deactivated state. The electronic price label system is configured to start transmitting transmissions from base stations (102) and/or electronic labels (100, 300) only when the detection means (112) of the electronic article surveillance system are in the deactivated state.