Sensor Node Sensing Threshold Determination via Signal Strength
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Solution Overview
Problem
Conventional methods for determining sensing thresholds in cognitive radio systems are inadequate, leading to incorrect detection probabilities and increased false alarms due to reliance on general channel models that do not account for specific geographic environments, and lack of information about primary user transmitters, resulting in either too low or too high sensing thresholds.
Innovation Solution
A method and device for determining a proper sensing threshold by measuring the received signal strength of used frequencies and calculating the path loss difference and transmit power difference between used and unused frequencies, allowing for adaptive threshold setting without prior knowledge of primary user transmitter information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional general channel models are used to determine sensing threshold, then the method is simple to implement, but the sensing threshold does not conform to actual environment leading to incorrect detection probability and increased false alarms
Solution Approach 1:
The patent changes the parameter determination approach from using fixed general channel models to dynamically determining path loss parameters based on actual received signal strength measurements. The sensing threshold is adjusted by calculating path loss difference between used and unused frequencies using real measurement data, transforming static model-based parameters into dynamic measurement-based parameters that adapt to actual environmental conditions.
2Measurement precision
If prior information about primary user transmitter is required for threshold determination, then the sensing threshold can be accurate, but the method cannot be applied universally to various transmitters
Solution Approach 1:
The patent enables the sensor node to determine its own sensing threshold autonomously by measuring received signal strength at used frequencies and calculating path loss characteristics itself. The node performs self-calibration by measuring actual signal conditions and deriving path loss difference parameters without requiring external database lookups or prior transmitter information, making the method universally applicable while maintaining accuracy.
3Reliability
If a uniform low sensing threshold is adopted to ensure detection, then false alarm probability increases and sensing overhead increases, but detection probability improves
Solution Approach 1:
The patent applies local quality by setting different sensing thresholds for different frequency bands based on their specific path loss characteristics. Instead of using a uniform threshold, the system calculates frequency-specific thresholds by determining path loss difference between used and unused frequencies, allowing each frequency to have an optimized threshold that matches its local propagation conditions, thereby reducing false alarms while maintaining detection probability.
Data Source
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AI summary
Embodiments of the present invention provide a sensing threshold determining method and a sensor node device. The sensing threshold determining method includes: measuring, by a sensor node, a target frequency band and determining used frequencies in the target frequency band and received signal strength of the sensor node at the used frequencies, where the used frequencies in the target frequency band include frequencies being used or having been used by a primary user transmitter in the target frequency band; and determining, by the sensor node, a sensing threshold for unused frequencies in the target frequency band according to the received signal strength at the used frequencies, where the unused frequencies include frequencies that are not used by the primary user transmitter in the target frequency band. With the embodiments of the present invention, a sensor node can determine a proper sensing threshold for unused frequencies.