RF-ID Tag EOS Detection via Sliding Window Variance Analysis
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Solution Overview
Problem
RF-ID systems face challenges in detecting the end of response signals from RF-ID tags within a short time, especially when response signals have different bit lengths, leading to communication failures and repeated attempts due to inability to determine the End Of Signal (EOS) within predetermined fixed times.
Innovation Solution
A method and apparatus that utilize a sliding window to measure variance values of response signals, compare them to a threshold obtained from continuous wave sections without response signals, and determine the EOS by counting instances where the variance value is below the threshold, enabling accurate detection and timely transmission of next command signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the reader waits for a fixed time to detect EOS of response signals, then communication timing is simplified, but detection accuracy deteriorates when response signals have different bit lengths
Solution Approach 1:
The patent changes the detection parameter from fixed time-based to variable time-based by adapting the detection window length according to the actual response signal duration. The reader dynamically adjusts the observation period to match the actual EOS position, thereby maintaining both operational simplicity and detection accuracy across different signal lengths.
Solution Approach 2:
The patent introduces dynamic adaptation in the EOS detection process by continuously monitoring signal characteristics and adjusting the detection parameters in real-time. This allows the system to transition from static fixed-time detection to dynamic adaptive detection that responds to varying response signal lengths.
2Device complexity
If the reader uses a fixed detection time window, then system complexity is reduced, but communication reliability deteriorates due to missed EOS detection
Solution Approach 1:
The patent implements feedback mechanisms where the detection result influences subsequent detection parameters. By using the detected signal characteristics to adjust the detection window and threshold settings for subsequent signals, the system improves reliability while maintaining manageable complexity through adaptive learning.
Solution Approach 2:
The patent performs preliminary analysis of response signal characteristics before final EOS determination. By pre-processing the signal to identify key features and predict appropriate detection parameters, the system prepares optimal detection settings in advance, improving reliability without significantly increasing overall system complexity.
3Measurement precision
If the reader extends the detection time to accommodate variable signal lengths, then EOS detection accuracy improves, but communication efficiency deteriorates due to increased idle time
Solution Approach 1:
The patent segments the detection process into multiple phases with different detection strategies. By dividing the response signal into segments and applying appropriate detection methods to each segment based on its characteristics, the system achieves accurate EOS detection for variable-length signals while minimizing the total detection time and maintaining communication efficiency.
Data Source
AI summary
When a reader of a Radio Frequency Identification (RF-ID) system sends out a command signal to the RF-ID tag and receives a response signal from the RF-ID tag, an End of Signal (EOS) of the received response signal is detected such that the next command signal can be transmitted within a time. Accordingly, response signal can be detected even under the environment of poor signal to noise ratio performance, and the EOS of the response signal from the RF-ID tag can be recognized with ease and speed.