Integrated RFID Receiver With Closed-Loop Self-Interference Cancellation
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Solution Overview
Problem
RFID readers are large and expensive due to interference from their own transmitters, increasing the cost and complexity of the receiver, which existing noise reduction methods have not adequately addressed.
Innovation Solution
An integrated noise-canceling RFID receiver with a baseband converter, summer, and quantizer that provides closed-loop noise control, using a delta-sigma modulator for feedback signal modulation and clock cancelation control to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional receiver design is used, then receiver functionality is provided, but self-interference from transmitter creates noise and degrades signal quality
Solution Approach 1:
The patent applies noise cancelation by generating a cancellation signal that is identical to the transmitter signal and subtracting it from the received signal. This converts the harmful self-interference into a beneficial cancellation effect, removing the transmitter's own noise from the received signal to improve signal quality.
Solution Approach 2:
The patent uses feedback through a feedback signal path that monitors the received signal and adjusts the cancellation signal accordingly. The feedback mechanism ensures that the cancellation signal accurately tracks and compensates for the transmitter signal, improving noise reduction effectiveness.
2Reliability
If noise cancelation circuitry is added to reduce self-interference, then signal quality improves, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple functions into the receiver circuitry: the baseband converter performs both mixing and noise cancelation, the summer combines the received signal with the cancellation signal, and the quantizer handles both conversion and feedback processing. This integration reduces the number of separate components while maintaining noise reduction capabilities.
Solution Approach 2:
The receiver circuitry is designed with multi-functionality where the baseband converter serves both as a mixer and noise cancelation device, the summer handles both signal combination and feedback integration, and the quantizer provides both analog-to-digital conversion and feedback signal generation. This universal design reduces overall system complexity.
3Reliability
If advanced noise reduction techniques are implemented, then interference cancelation improves, but power consumption increases
Solution Approach 1:
The patent employs periodic sampling and quantization operations that process signals at discrete intervals rather than continuously. The feedback signal is generated and applied periodically to adjust the cancellation signal, reducing power consumption compared to continuous processing while maintaining effective interference cancelation.
Solution Approach 2:
The patent changes operating parameters dynamically through feedback control, adjusting the cancellation signal based on the received signal conditions. This parameter adaptation allows the system to maintain effective noise reduction while optimizing power consumption by avoiding unnecessary processing when interference is minimal.
Data Source
AI summary
Aspects and features of this disclosure include an RFID reader with an integrated noise-canceling RFID receiver. The receiver includes a baseband converter configured to receive an RFID signal and a cancelation signal. The baseband converter acts as a received signal mixer and also provides noise cancelation using the cancelation signal. A modulated feedback signal completes closed-loop signal path that automatically provides noise control, both noise shaping and noise filtering, improving the receiving performance by efficiently reducing or eliminating noise that would otherwise be produced by the transmitter of the RFID reader.