NFC Signal Delay Compensation for ISO 14443 Compliance
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Solution Overview
Problem
Existing RFID communication systems with NFC devices and smart cards connected via protocol converters face signal delays that violate ISO 14443 timing specifications due to incompatible digital and analog interfaces, leading to non-compliant communication with RFID readers/writers.
Innovation Solution
A device with signal pattern shortening and response delaying means is integrated into the NFC device to detect and adjust signal patterns, allowing for internal signal delays to be compensated, ensuring compliance with ISO 14443 by shortening signal pauses and adjusting response times accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a protocol converter is used to connect NFC device and smart card, then compatibility between digital and analog interfaces is improved, but signal delays occur that violate ISO 14443 timing specifications
Solution Approach 1:
The patent applies preliminary action by measuring the signal delay through test signals before actual communication, storing the measured delay value, and then using this pre-obtained information to compensate for delays during normal operation. The compensation value is calculated in advance and applied to adjust signal timing, ensuring ISO 14443 compliance without requiring real-time complex calculations.
2Adaptability or versatility
If signal conversion is performed in protocol converter, then interface compatibility is achieved, but internal signal delays are introduced that affect communication timing
Solution Approach 1:
The patent implements feedback by sending test signals through the protocol converter, measuring the actual signal delay introduced by the conversion process, and using this measured feedback information to calculate compensation values. This closed-loop approach ensures that the timing precision is maintained by continuously referencing the actual delay characteristics of the specific hardware configuration.
3Productivity
If direct connection between NFC device and antenna is made, then signal transmission efficiency is improved, but smart card connectivity without separate antenna is lost
Solution Approach 1:
The patent applies merging by integrating both NFC device functionality and smart card functionality into a single unified device. The protocol converter enables the smart card interface to share the same antenna resource with the NFC device, allowing one antenna to serve dual purposes - receiving electromagnetic signals for NFC communication while also providing contactless card functionality through the protocol conversion interface.
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
The solution effectively compensates for internal signal delays, enabling standard NFC devices and smart cards to communicate compliantly with RFID readers/writers, adhering to ISO 14443 specifications despite the use of non-compliant protocol converters.
Implementation Method 1
the NFC device is coupled to an antenna to receive electromagnetic signals from an RFID reader/writer and to transmit response signals to the RFID reader/writer by modulating received electromagnetic signals
Data Source
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AI summary
An RFID communication system comprises an NFC device (11) and a smart card (2) with contactless card functionality, wherein the NFC device (11) and the smart card (2) are couplable to each other via a protocol converter (7), wherein the NFC device (11) is coupled to an antenna (3) to receive electromagnetic signals (ES) from an RFID reader/writer and to transmit response signals (RS) to the RFID reader/writer by modulating received electromagnetic signals (ES). The electromagnetic signals (ES) contain first and second characteristic components (FE, RE) which define the begin and the end of a predefined signal pattern (PA), wherein the second characteristic component triggers a predefined response delay time (FDT) at the expiration of which the RFID communication system has to respond to the RFID reader/writer. A device (12) for compensating signal delays is provided that comprises signal pattern shortening means (13).