RFID Tag Silence Code Encoding for Collision Resistance
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Solution Overview
Problem
Prior art RFID technology is inefficient when multiple tags respond simultaneously, leading to signal collisions that delay the identification process due to the inability to decode signals correctly in the presence of collisions.
Innovation Solution
A fast RFID tag identifying method using silence codes that encode bit pairs, allowing for simultaneous decoding of multiple tags' IDs even in the presence of signal collisions, by employing an encoding step, transmitting step, and decoding step to manage superposition of silence codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple tags respond simultaneously in prior art RFID technology, then signal collision occurs, but the reader can still identify tags through further processing, however this delays the identifying process
Solution Approach 1:
The patent applies preliminary action by pre-encoding tag ID bits into silence codes with specific properties before transmission. The encoding is designed in advance so that even when multiple tags transmit simultaneously, the superposition of silence codes can be decoded to recover the original ID bits. This preliminary encoding structure enables collision resistance without requiring additional processing time after collision occurs.
Solution Approach 2:
The patent changes the parameter representation by transforming binary ID bits into silence codes with specific temporal patterns. The silence code encoding changes the signal characteristics such that the superposition of multiple silence codes contains sufficient information to reconstruct the original bit pairs. This parameter transformation allows the system to handle simultaneous transmissions that would otherwise be lost in collision.
2Reliability
If the reader waits for sequential tag responses to avoid signal collision, then identification accuracy is maintained, but the identifying process speed decreases
Solution Approach 1:
The patent converts the harmful effect of signal collision into a beneficial outcome. Instead of treating simultaneous transmissions as errors to be avoided, the silence code encoding transforms the superposition of collided signals into a decodable form. The collision itself becomes useful because the superposition of silence codes retains information about the original bit pairs, allowing the reader to identify multiple tags simultaneously rather than sequentially.
3Measurement precision
If additional processing is performed to resolve signal collisions, then tag identification accuracy is improved, but system complexity and processing time increase
Solution Approach 1:
The complexity is moved to the encoding stage rather than the decoding stage. The silence code encoding is performed in advance by the tags, creating a structure that is inherently resistant to collision losses. At the reader side, the decoding process is simplified because the preliminary encoding has already prepared the signals for reliable recovery even under collision conditions, avoiding the need for complex collision resolution algorithms.
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 the reader to decode tag IDs in real-time without additional processing, significantly accelerating the identification process even when multiple tags respond at the same time, overcoming signal collision issues.
Implementation Method 1
the reader can receive signals from the tag and read the unique tag ID stored in the tag
Implementation Method 2
the superposition of silence codes transmitted by tags and decode it into a set of the ID bit pairs of the tags
Data Source
AI summary
A fast RFID tag identifying method includes an encoding step for encoding a pair of bits to be expressed by an RFID tag into a silence code to be used in a transmitting step for the RFID tag. The silence code is arranged such that the superposition of a plurality of silence codes from a plurality of RFID tags is decoded into a set of pairs of bits to be expressed by the RFID tags.