Passive RFID Transponder Coding for Direct Carrier Modulation
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Solution Overview
Problem
Passive RFID transponders face challenges in achieving high data rates with minimal hardware complexity and energy consumption due to weak coupling with RFID readers, which limits the signal detection and requires complex two-stage modulation.
Innovation Solution
A passive RFID transponder with a coder and modulator that generates a digital coded data stream with an initialization bit sequence, allowing direct amplitude modulation of the carrier signal, eliminating the need for a subcarrier signal and reducing hardware complexity, while ensuring stable synchronization by changing the data value after a predefined number of bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-stage modulation with subcarrier signal is used, then data transmission can be achieved with weak coupling, but hardware complexity and energy consumption increase
Solution Approach 1:
The patent extracts and eliminates the subcarrier signal stage from the traditional two-stage modulation system, implementing direct amplitude modulation of the carrier signal. This removes the unnecessary intermediate modulation layer while maintaining reliable signal detection through optimized direct modulation schemes.
Solution Approach 2:
The patent introduces an initialization bit sequence as an intermediary element that enables the reader to determine maximum data frequency and synchronize with the transponder. This intermediary structure facilitates reliable communication without requiring complex two-stage modulation hardware.
2Reliability
If two-stage modulation with subcarrier signal is used, then data transmission can be achieved, but maximum data rate is limited by subcarrier frequency
Solution Approach 1:
The patent removes the subcarrier signal constraint by implementing direct carrier modulation. This extraction of the limiting subcarrier stage allows the system to achieve maximum data rates determined only by the carrier frequency and signal processing capabilities, not by an intermediate subcarrier frequency.
Solution Approach 2:
The patent changes the modulation parameter from indirect subcarrier modulation to direct carrier amplitude modulation. This parameter change enables the system to operate at higher data rates by eliminating the subcarrier frequency bottleneck while maintaining transmission reliability through optimized direct modulation and synchronization techniques.
3Device complexity
If direct amplitude modulation is used, then hardware complexity and energy consumption are reduced, but synchronization stability may be compromised
Solution Approach 1:
The patent applies preliminary action by incorporating an initialization bit sequence at the beginning of data transmission. This preliminary structure allows the reader to establish synchronization and determine maximum data frequency before the actual data transmission begins, ensuring stable synchronization throughout the communication process.
Solution Approach 2:
The patent implements feedback mechanisms where the reader evaluates the initialization bit sequence to determine maximum data frequency and adjusts synchronization parameters accordingly. This feedback loop ensures stable synchronization is maintained throughout the data transmission process while using simple direct amplitude modulation.
4Use of energy by moving object
If direct amplitude modulation is used, then energy consumption is reduced, but the reader needs to determine maximum data frequency from initialization sequence
Solution Approach 1:
The transponder uses self-service by embedding maximum data frequency information directly in the initialization bit sequence structure. The transponder automatically configures its transmission parameters and the reader automatically extracts the maximum data frequency information, eliminating the need for separate configuration protocols and reducing overall system complexity.
Solution Approach 2:
The patent changes the approach from complex energy optimization algorithms to a simpler parameter-based solution. By encoding maximum data frequency information in the initialization sequence, the system achieves energy efficiency through simpler direct modulation while the reader determines operational parameters through straightforward analysis of the initialization bits.
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
This approach increases data rates by eliminating subcarrier signal limitations, reduces energy consumption, and simplifies hardware, enabling efficient data transmission and synchronization with the RFID reader.
Implementation Method 1
the RFID reader uses inductive coupling to provide the energy needed by the passive RFID transponder
Implementation Method 2
The modulator is configured to modulate an amplitude of a carrier signal with the digital coded data stream to provide an amplitude-modulated coded signal
Data Source
AI summary
A passive RFID transponder includes a coder and a modulator. The coder generates a digital coded data stream based on a digital data stream to be transmitted. The digital coded data stream includes an initialization bit sequence having a maximum data frequency of the digital coded data stream. Furthermore, the digital coded data stream changes its value at the latest after a predefined number of bits. The modulator modulates an amplitude of a carrier signal with the digital coded data stream to provide an amplitude-modulated coded signal.