RFID Tag Signpost Timing Synchronization
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Solution Overview
Problem
Existing RFID tracking systems are inadequate in accurately transmitting timing information and managing tag signals, leading to unreliable event detection and location tracking due to interference and noise in environments with multiple tags and readers.
Innovation Solution
The system includes a tag that receives wireless signpost signals with timing data, determines event time information, and transmits tag signals with a tag code and time information, using orthogonal LF antennas and UHF signals with slotted aloha protocol to minimize interference, ensuring accurate and synchronized timing across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signpost signals are transmitted with a short transmission range to minimize interference, then signal-to-noise ratio is improved, but tracking coverage area is reduced
Solution Approach 1:
The system divides the tracking area into multiple zones with signposts positioned at strategic locations. Each signpost covers a localized area with short-range signals, and multiple signposts work together to provide comprehensive coverage. This segmentation allows each signpost to maintain short transmission range for high reliability while the collective system achieves broad coverage.
Solution Approach 2:
The tag acts as an intermediary that receives short-range signpost signals and retransmits them as long-range tag signals to readers. This intermediary function allows the system to maintain short transmission ranges for signpost-to-tag communication (ensuring high signal-to-noise ratio) while achieving broad coverage through tag-to-reader communication.
2Area of stationary object
If tags transmit signals with long transmission range to ensure coverage, then tracking coverage area is improved, but signal interference increases
Solution Approach 1:
The system segments the communication function into two parts: signposts transmit short-range signals to nearby tags, and tags transmit long-range signals to readers. This segmentation allows long-range transmission to occur only at the tag-to-reader stage, where interference is managed through the tag's selective reception and retransmission of only relevant signals.
Solution Approach 2:
The tag serves as an intermediary that filters and selectively retransmits signals. It receives short-range signpost signals, processes them to extract relevant information, and then transmits processed signals with longer range to readers. This intermediary function reduces interference by eliminating redundant or irrelevant signal transmissions.
3Measurement precision
If timing data is included in signpost signals to improve event timing accuracy, then measurement precision is improved, but signal complexity increases
Solution Approach 1:
The system embeds timing data as a specific parameter within the signpost signal structure. By allocating dedicated time slots or specific bit positions for timing information, the system achieves precise event timing measurement while maintaining a regular and predictable signal format that doesn't excessively increase complexity.
Data Source
AI summary
A tag receives wireless signpost signals that include timing data, determines time information associated with an event as a function of the timing data, and transmits a wireless tag signal that contains the time information. In a another configuration, a signpost transmits wireless signpost signals having a selected transmission range; a reader proximate to the signpost receives wireless tag signals with a reception range that is approximately the same as the selected transmission range; and a tag movable relative to the signpost and reader responds to receipt of a wireless signpost signal by transmitting a wireless tag signal containing a tag code associated with the tag.