RF Echo Cancellation via Feedback Loop for RFID Transceivers
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Solution Overview
Problem
RFID systems face performance issues due to reflection and coupling in RF transceivers, leading to high voltage standing wave ratio (VSWR) that can cause receiver saturation, particularly in mobile devices where size and power efficiency are concerns.
Innovation Solution
A system and method that utilize a feedback loop to isolate and cancel radio frequency echo signals by demodulating reflection signals into in-phase and quadrature signals, filtering to isolate error components, and combining these with feedback signals to minimize VSWR, employing components like circulators, directional couplers, and digital signal processing to achieve echo cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transceivers are designed to minimize VSWR, then receiver performance is improved, but device size and power consumption increase
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is processed to generate an echo cancellation signal that is fed back to cancel the reflected signal. This feedback loop allows the system to dynamically adjust and minimize VSWR effects without requiring complex hardware designs, thereby improving receiver performance while keeping device size manageable.
Solution Approach 2:
The patent replaces traditional mechanical or hardware-based VSWR minimization techniques with signal processing methods. By using digital signal processing to generate echo cancellation signals rather than relying on complex analog circuitry, the system achieves better receiver performance without proportionally increasing device complexity or size.
2Reliability
If transceivers are designed to minimize VSWR, then receiver performance is improved, but power consumption increases
Solution Approach 1:
The feedback loop processes the received signal to generate cancellation signals that actively compensate for reflected signals. This dynamic feedback mechanism allows the system to maintain optimal receiver performance by continuously adjusting to minimize VSWR effects, achieving better performance without excessive power consumption compared to static hardware solutions.
Solution Approach 2:
The patent substitutes power-intensive hardware-based VSWR minimization circuits with more efficient signal processing techniques. By using digital signal processing algorithms rather than complex analog circuits, the system achieves similar or better receiver performance with reduced power consumption, making it suitable for mobile applications.
3Reliability
If echo cancellation is implemented, then VSWR is reduced, but device complexity increases
Solution Approach 1:
The patent designs the echo cancellation system to serve multiple functions within a unified architecture. The same signal processing components used for echo cancellation also support other receiver functions, reducing the overall number of discrete components needed. This multi-functional approach achieves VSWR reduction while minimizing the increase in device complexity.
Solution Approach 2:
The patent replaces multiple discrete hardware components with integrated signal processing functionality. By using digital signal processing and software-based echo cancellation algorithms, the system achieves VSWR reduction without requiring proportionally more physical components, thereby limiting the increase in device complexity.
Data Source
AI summary
A system comprising a transmitter element creating an interrogation signal and transmitting the interrogation signal and a receiver element receiving a reflection signal of the interrogation signal and combining the reflection signal and a feedback signal to cancel at least a portion of radio frequency echo signals in the reflection signal.