RFID Range Determination via Minimum Detection Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless sensor networks face challenges in determining the location of nodes within communication systems due to severe resource constraints such as energy, bandwidth, and processing power limitations, which affect location accuracy and require a balance between resource usage and performance.
Innovation Solution
A method and apparatus that use the minimum transmission power needed to detect a target node to indicate distance, adjusting transmit power to maintain a desired detection rate, and displaying this information to facilitate node location, which is less sensitive to environmental changes and aids in power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If resource consumption is minimized in wireless sensor networks, then energy efficiency is improved, but location accuracy deteriorates
Solution Approach 1:
The system transmits queries at multiple power levels rather than continuously at maximum power. By using partial action (intermittent transmissions at varying power levels) to measure detection rates, the system achieves location information with reduced energy consumption while maintaining acceptable accuracy through statistical sampling of detection rates at different power levels.
Solution Approach 2:
The system dynamically changes the transmission power parameter to measure detection rates at different power levels. By varying this parameter and observing how detection rate changes with power level, the system derives location information without requiring continuous high-power transmissions, thus balancing energy efficiency with location accuracy.
2Measurement precision
If transmit power is increased to maintain detection rate, then location accuracy is improved, but energy consumption increases
Solution Approach 1:
Instead of continuously transmitting at high power, the system uses partial action by transmitting at multiple power levels intermittently. The detect rate measurement uses a limited number of queries at different power levels to estimate location, avoiding continuous high-power transmission while maintaining sufficient measurement precision through statistical sampling.
Solution Approach 2:
The system uses the natural relationship between transmit power and detection rate to self-determine location information. By measuring how detection rate varies with power level, the system derives range information without requiring external reference systems or additional sensors, achieving location accuracy through self-service measurement.
3Measurement precision
If detection rate is increased for better location estimation, then location accuracy is improved, but bandwidth consumption increases
Solution Approach 1:
The system obtains sufficient location accuracy through partial detection rate measurements at multiple power levels rather than continuous high-rate detection. By using a limited number of queries at different power levels to estimate the detect rate curve, the system achieves adequate location precision with reduced bandwidth consumption compared to continuous high-rate detection.
4Measurement precision
If processing power is increased for more accurate location calculation, then location accuracy is improved, but device complexity increases
Solution Approach 1:
The system extracts location information from the relationship between transmit power and detection rate without requiring complex processing algorithms. By measuring detection rates at a few discrete power levels and using simple interpolation or curve fitting to estimate the power level corresponding to a reference detection rate, the system achieves location accuracy with minimal processing power and device complexity.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and apparatus for determining a range within a wireless communication system is provided herein. The range information can then be used to locate a node (e.g., an asset tag). During operation, the minimum transmission power of a source transceiver (e.g., an RFID reader) that enables a tag to be detected will be used to indicate distance. Changes in transmit power will be used to indicate relative changes in distance to a particular node. The reader will be configured to always operate at a transmission power that will result in a certain percentage (e.g., 50%) detection rate for a target transceiver (e.g., an RFID asset tag). As the reader moves closer to the tag, the minimum detection power will decrease; as it moves farther from the tag, the minimum detection power will increase. This information is displayed to give a general change in range information between the RFID reader and the asset tag (e.g., increasing range or decreasing range). An individual will be able to easily locate the asset tag by using the displayed information.