RSS Range Estimation Bias Correction for Limited Sensitivity Receivers
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Solution Overview
Problem
Existing range estimation methods in wireless sensor networks and communication networks are affected by the limited sensitivity of receivers, leading to systematic biases and inaccurate variance indicators in range measurements due to signal truncation, especially in non-ideal receivers.
Innovation Solution
A method that corrects the systematic bias in distance estimators by calculating and accounting for the moments of the distorted probability density function of the distance estimate, using path loss parameters and the detection threshold to adjust the range estimates and variances, thereby providing accurate and unbiased range measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RSS measurement is used for range estimation in wireless networks, then positioning capability is enabled, but systematic bias is introduced due to limited receiver sensitivity
Solution Approach 1:
The patent changes the parameter of the probability density function by introducing a truncation point parameter that accounts for the receiver's detection threshold. This allows the system to model the distorted PDF caused by limited sensitivity and calculate corrected range estimates that compensate for the systematic bias, thereby improving measurement precision without sacrificing reliability
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the received signal strength distribution and adjusts the range estimation process by incorporating the truncated PDF model. The calculated bias is fed back into the estimation algorithm to correct subsequent measurements, ensuring both high precision and reliability in positioning
2Reliability
If signal truncation is applied in receivers with limited sensitivity, then detection capability is maintained, but probability density function distortion occurs
Solution Approach 1:
The patent converts the harmful effect of signal truncation (which distorts the PDF and introduces bias) into a beneficial factor by explicitly modeling the truncation point in the PDF. The known detection threshold becomes a parameter that enables accurate correction of the distortion, transforming the source of error into a tool for improving measurement precision while maintaining detection reliability
3Device complexity
If conventional range estimators are used without bias correction, then computational simplicity is maintained, but positioning accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating the bias correction factor based on the truncated PDF model and the known detection threshold. This correction is prepared in advance and then applied to the range estimation process, adding minimal computational complexity while significantly improving positioning accuracy compared to conventional estimators
Data Source
AI summary
The present invention relates to a method for estimating the range between a radio signal emitter and a receiver. A first range estimate is obtained (330) from the signal strength of the received signal (310), a path loss model with predetermined path loss parameters (320). This range estimate is further corrected (350) with a systematic bias (340) depending upon the actual finite sensitivity of the receiver. Optionally a corrected variance of the range estimate can also be calculated (360).