Reader FSK Modulation for Wireless Tag Signal Source Identification
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Solution Overview
Problem
In scenarios where wireless tags are positioned within overlapping communication ranges of multiple readers with the same transmission frequency band, it is challenging to identify which reader's signal a reflected wave from the wireless tag corresponds to, leading to potential erroneous data reception without complicating the wireless tag's configuration.
Innovation Solution
A communication apparatus and method that employs quadrature modulation, transmission, reception, demodulation, and decoding units to prevent erroneous data reception from another reader by using frequency shift keying (FSK) modulation and demodulation, allowing the reader to identify and validate the intended data source without complicating the wireless tag's configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data transmission on the wireless tag side is devised to enable reader identification, then the reader can identify which reader's signal the reflected wave corresponds to, but the function required for the wireless tag advances and the configuration becomes complicated
Solution Approach 1:
Instead of making the wireless tag complicated to identify the reader, the patent inverts the approach by making the reader capable of identifying its own transmitted signal through FSK modulation. The reader embeds identification information in the transmitted signal and verifies it in the received reflected wave, keeping the wireless tag configuration simple while achieving reliable reader identification.
Solution Approach 2:
The patent uses FSK (Frequency Shift Keying) modulation to encode identification information in the transmitted signal by varying the frequency parameter. This allows the reader to distinguish its own signal from others without complicating the wireless tag, as the frequency-modulated signal can be easily generated and detected.
2Area of stationary object
If multiple readers transmit signals in the same frequency band with overlapping ranges, then communication coverage is extended, but it becomes impossible to identify which reader's signal the reflected wave corresponds to
Solution Approach 1:
The patent applies FSK modulation to encode unique identification information for each reader in the transmitted signal's frequency parameter. This allows multiple readers to operate in the same frequency band simultaneously while maintaining the ability to identify which reader's signal is being reflected, preventing information loss about signal source identification.
3Reliability
If FSK modulation is used for signal transmission, then accurate reader identification is achieved, but the processing complexity on the reader side increases
Solution Approach 1:
The patent replaces complex signal processing mechanisms with standard FSK modulation and demodulation techniques. By using well-established FSK methods, the reader can achieve accurate signal identification without requiring complex custom processing circuits, thus balancing reliability with manageable processing complexity.
Data Source
AI summary
A communication apparatus includes a generation unit that generates the first I signal and the first Q signal as signals that allow a carrier wave to undergo frequency shift keying with predetermined modulated data and inputs the first I signal and the first Q signal to a quadrature modulation unit. A first demodulation unit and the first decoding unit demodulate and decode first data that undergoes amplitude shift keying and is transmitted from the wireless tag. A second demodulation unit and the second decoding unit demodulate and decode second data that undergoes frequency shift keying from a wireless signal output from the wireless tag. A comparison unit compares the second data and the modulated data to each other. The processor executes, when matching between the second data and the modulated data is confirmed by the comparison unit, data processing on the first data.