RFID Tag Validation Using Reference Phase Comparison
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Solution Overview
Problem
Existing communication devices struggle to accurately determine whether a wireless tag is within a predetermined area due to phase changes caused by distance and environmental factors, leading to potential erroneous identification of commodities.
Innovation Solution
A communication device equipped with an antenna, a reception unit, and a determination unit that uses phase differences between signals from a reference tag and a reading target tag to validate the location of the target tag within a predetermined area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If phase-based location determination is used to identify wireless tags within a predetermined area, then the ability to detect tag location is improved, but measurement precision deteriorates due to phase changes caused by distance and environmental factors
Solution Approach 1:
A reference tag is introduced as an intermediary element to mediate the phase measurement process. The reference tag provides a known phase reference that allows the system to distinguish between phase changes due to antenna movement and phase changes due to environmental factors or distance variations. By comparing the phase of signals from the reference tag with signals from target tags, the system can accurately determine tag locations despite phase instability.
Solution Approach 2:
The reference tag serves multiple functions simultaneously: it acts as a phase reference, a location marker, and an environmental compensation element. This multi-functionality allows the system to use a single additional component to resolve multiple sources of phase measurement error, including distance variations and environmental interference.
2Speed
If wireless communication is established with all detected tags, then the speed of commodity identification is improved, but reliability deteriorates due to erroneous identification of tags outside the predetermined area
Solution Approach 1:
The reference tag acts as a mediator that enables accurate spatial filtering. By establishing a known phase relationship with the reference tag, the system can determine whether target tags are within the predetermined area based on their phase difference relative to the reference tag. This allows the system to quickly identify valid tags while excluding invalid ones, maintaining both speed and reliability.
Solution Approach 2:
The system uses the phase information from the reference tag as feedback to validate the location of target tags. This feedback mechanism allows real-time verification of tag positions, enabling the system to accept or reject tag readings based on their spatial validity, thus preventing erroneous identification while maintaining fast processing.
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
Prevents the reading of wireless tags not guaranteed to be within the predetermined area as valid, ensuring accurate identification of commodities and preventing erroneous registration.
Implementation Method 1
uses the antenna to sequentially receive signals wirelessly transmitted from a reference tag whose relative position to the antenna is known and a reading target tag different from the reference tag
Data Source
AI summary
A wireless tag that is not guaranteed to be located within a predetermined area is prevented from being read as a valid wireless tag. A communication device includes: an antenna; a reference tag; a reception unit; and a determination unit. The reception unit uses the antenna to sequentially receive signals wirelessly transmitted from a reference tag whose relative position to the antenna is known and a reading target tag different from the reference tag. The determination unit determines that the signal transmitted from the reading target tag and received by the reception unit is invalid based on a phase of the signal transmitted from the reference tag and received by the reception unit.