Contactless Card Anti-Collision via Byte-Wise Pulse Counting
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Solution Overview
Problem
Conventional anti-collision methods for contactless interface devices, such as contactless IC and RFID cards, require complex arithmetic operations and are time-consuming due to bit unit identification, pseudo unique proximity card identifiers, and unique identification processes, leading to confusion and inefficiency when multiple cards approach a reader.
Innovation Solution
The method involves requesting contactless cards to transmit unique identifiers as fixed-byte positive pulses, allowing for simultaneous reception and comparison to determine the presence of multiple cards, thereby simplifying the identification process without requiring complex card operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional anti-collision methods use bit unit identification or pseudo unique proximity card identifiers, then card identification can be achieved, but the process becomes time-consuming and complex due to required card operations
Solution Approach 1:
The patent segments the unique identifier transmission into fixed-byte units rather than bit-by-bit processing. Each card transmits its unique identifier in fixed-byte segments, allowing the reader to process and compare identifiers more efficiently without requiring complex bit-level operations at the card level, thus reducing identification time while maintaining accuracy
Solution Approach 2:
The patent inverts the conventional approach by having cards transmit fixed-byte positive pulses representing unique identifiers rather than requiring the reader to perform complex slot-based or bit-level anti-collision algorithms. This reversal simplifies card operations significantly while enabling the reader to efficiently detect and resolve collisions through pulse counting
2Measurement precision
If conventional methods require complex arithmetic operations within each card for anti-collision, then card identification can be performed, but device complexity increases
Solution Approach 1:
The patent extracts the complex anti-collision arithmetic operations from the card and relocates them to the reader side. Cards only need to transmit fixed-byte positive pulses of their unique identifiers, while the reader performs the pulse counting and collision detection algorithms, significantly reducing card complexity while maintaining identification accuracy
Solution Approach 2:
The patent implements a self-service mechanism where cards automatically transmit their unique identifiers as fixed-byte positive pulses without requiring complex processing. The transmission is straightforward and self-contained, while the complex anti-collision resolution is handled externally by the reader system
3Reliability
If multiple cards approach the reader simultaneously using conventional methods, then card presence can be detected, but signal confusion occurs due to multiple concurrent signals
Solution Approach 1:
The patent uses periodic pulse transmission where cards transmit their unique identifiers as a series of fixed-byte positive pulses. The reader counts these pulses to determine the number of responding cards, allowing it to manage multiple concurrent signals systematically by processing them in organized transmission cycles rather than as continuous overlapping signals
Solution Approach 2:
The patent uses distinct positive pulse signals as a form of signal differentiation. Each card transmits its unique identifier through distinctive positive pulse patterns, allowing the reader to differentiate between multiple cards through pulse counting and pattern recognition, preventing signal confusion that would occur with conventional modulation methods
Data Source
AI summary
Contactless cards and a corresponding anti-collision coupling method are provided, where the method includes requesting that the cards transmit their unique identifiers that each include a fixed number of bytes, receiving the unique identifiers simultaneously as byte-wise positive pulses, counting the received positive pulses, and determining that more than one card responded if the number of received positive pulses exceeds the fixed number of bytes; and where the contactless cards each include a unique identifier having a number of bytes, a receiver for receiving an anti-collision command indicative of a desired identifier byte, a comparator in signal communication with the receiver for comparing the desired identifier byte with a corresponding byte of the unique identifier, and a transmitter responsive to the comparator for transmitting the unique identifier as byte-wise positive pulses if the desired identifier byte matches the corresponding byte of the unique identifier.