Wireless Node Positioning Using LOS Delay Re-Evaluation
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Solution Overview
Problem
Existing position estimation methods for terminal nodes in wireless networks suffer from inaccuracies due to incorrect identification of line of sight (LOS) time delay values, particularly when non-line of sight (NLOS) signals are attenuated, leading to errors in determining the position of terminal nodes.
Innovation Solution
A method involving determining time delay values and metrics for access nodes, using power delay profiles and machine learning to identify LOS conditions, and refining position estimates based on high-confidence LOS time delay values, while correcting errors from initially low-confidence LOS identifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position estimation methods are used, then the position of terminal nodes can be determined, but the accuracy is poor due to incorrect identification of LOS time delay values when NLOS signals are attenuated
Solution Approach 1:
The patent implements feedback by using the initially determined position estimate to re-evaluate and correct the LOS time delay value identifications. The system feeds the position estimate back into the analysis of time delay values, using geometric consistency checks to identify and correct incorrect LOS/NLOS classifications, thereby improving measurement precision.
Solution Approach 2:
The patent performs preliminary action by first determining a position estimate using available time delay values before finalizing the LOS identification. This preliminary position estimate is then used to validate and correct the LOS time delay value selections, ensuring that the final position determination is based on accurately identified LOS paths.
2Quantity of substance
If all available time delay values are used for position estimation, then more data is available for calculation, but errors from incorrect LOS identification propagate and reduce accuracy
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the selection of time delay values based on their identified LOS/NLOS status and geometric consistency with the position estimate. Rather than using all available time delay values uniformly, the system selectively weights or excludes values based on their reliability, changing the effective parameter set used in position calculation.
Solution Approach 2:
The patent implements local quality by applying different treatment to different time delay values based on their individual characteristics and geometric consistency. Each time delay value is evaluated locally against the position estimate, and only those that satisfy geometric constraints are used for final position determination, ensuring high-quality inputs for the calculation.
3Illumination intensity
If NLOS signals are attenuated, then LOS signals become more prominent, but this leads to misidentification of NLOS as LOS and causes position estimation errors
Solution Approach 1:
The patent applies preliminary anti-action by proactively checking for geometric inconsistencies between the determined position estimate and the identified LOS time delay values. Before finalizing the position estimate, the system anticipates potential misidentifications and corrects them by verifying that selected LOS paths are geometrically consistent with the position solution, preventing error propagation.
Solution Approach 2:
The system uses feedback by continuously validating LOS time delay value selections against the position estimate. When geometric inconsistencies are detected, the system re-evaluates the LOS/NLOS classification and corrects misidentifications, ensuring that attenuated NLOS signals are not incorrectly treated as LOS signals in the final position calculation.
Data Source
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AI summary
An apparatus comprising at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: determining, for a terminal node, at least one time delay value for a plurality of access nodes; determining at least one metric for the access nodes, the at least one metric indicative of probability of line of sight conditions between the terminal node and the access nodes; determining, based, at least in part, on the at least one metric, a first set of line of sight time delay values having an associated probability of line of sight conditions above a threshold; determining, based, at least in part, on the at least one metric, a second set of time delay values having an associated probability of line of sight conditions below the threshold; determining a position estimate of the terminal node based, at least in part, on the first set of line of sight time delay values; determining, based at least in part on the position estimate of the terminal node, at least one line of sight time delay value of the second set; and determining a new estimate of the position of the terminal node based, at least in part, on the at least one determined line of sight time delay value of the second set.