Wireless Node Positioning Using Line-of-Sight Delay Filtering
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Solution Overview
Problem
Existing wireless networks face challenges in accurately estimating the position of terminal nodes due to uncertainties in line of sight conditions, leading to errors in determining time delay values.
Innovation Solution
An apparatus and method that determine time delay values for multiple access nodes, calculate metrics indicative of line of sight conditions, and refine position estimates by distinguishing between high-confidence and low-confidence time delay values using power delay profiles and machine learning techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time delay values are determined for position estimation without filtering, then the positioning process can proceed quickly, but the accuracy of position estimation deteriorates due to incorrect line of sight time delay values
Solution Approach 1:
The patent applies preliminary action by calculating metrics indicative of line of sight conditions before determining the final position estimate. This allows the system to pre-filter time delay values based on line of sight probability metrics, removing incorrect values before they can degrade the position estimation accuracy. The filtering operation is performed in advance as a preparatory step.
Solution Approach 2:
The patent introduces an intermediary element - the line of sight metric calculation - that mediates between the raw time delay values and the final position estimation. This intermediary layer analyzes power delay profiles and determines probabilities of line of sight conditions, acting as a filter that separates correct from incorrect time delay values before position calculation.
2Reliability
If all time delay values are used for position estimation, then more data is available for calculation, but the reliability deteriorates due to inclusion of incorrect line of sight values
Solution Approach 1:
The patent applies the taking out principle by extracting and removing incorrect line of sight time delay values from the dataset before position estimation. The system calculates metrics for each time delay value, identifies those with low probability of line of sight conditions, and excludes them from the final calculation. This extraction process improves reliability by eliminating harmful data points.
Solution Approach 2:
The patent applies local quality by treating each time delay value individually with its own line of sight probability metric, rather than applying a uniform approach to all values. Each time delay value is assessed based on its specific power delay profile characteristics, allowing the system to selectively include or exclude values based on their individual reliability.
3Measurement precision
If line of sight metrics are calculated for all access nodes, then more accurate filtering is achieved, but the energy consumption increases due to additional processing
Solution Approach 1:
The patent applies partial action by calculating line of sight metrics selectively rather than for all access nodes uniformly. The system determines metrics for access nodes based on their relevance to the terminal node's position estimation, performing the energy-intensive metric calculation only where necessary to achieve sufficient accuracy.
Data Source
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.