Wireless Positioning Using Delay Spread Extraction
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Solution Overview
Problem
Current wireless position determining technologies, such as GPS, face challenges in non-line-of-sight environments and indoors due to signal interference, near-far problems, and precision issues with methods like AOA, RSSI, TOA, and TDOA, which degrade performance and accuracy.
Innovation Solution
A method and apparatus that measure propagation delay taps of signals, extract delay spread information, and calculate distances between transmission and reception ends to improve position determination precision using delay spread data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS signal reception is used for position determination, then high precision position information can be obtained, but it cannot be received in areas not visible from satellites (indoor environments, urban canyons)
Solution Approach 1:
The patent introduces wireless communication base stations as intermediary nodes to relay position determination information. Instead of directly receiving satellite signals, terminals receive position data from base stations that have previously determined their positions using GPS, thereby enabling position determination in environments where direct satellite reception is blocked.
Solution Approach 2:
The patent uses base stations to copy and transmit position determination results to terminals. Rather than requiring each terminal to independently receive and process satellite signals, the base stations capture position information and replicate it to multiple terminals in their coverage area, enabling GPS-denied environments to obtain position data.
2Adaptability or versatility
If AOA method is used for position determination, then position can be determined without direct satellite visibility, but precision significantly degrades when there is no line-of-sight
Solution Approach 1:
The patent merges multiple position determination methods and data sources. Base stations use TOA/TDOA methods to determine terminal positions, while terminals can also use AOA methods. The system combines results from multiple base stations and multiple measurement techniques to achieve accurate position determination in non-LOS environments without relying solely on AOA's angle measurements.
Solution Approach 2:
The patent changes the measurement parameters from angle-based (AOA) to time-based (TOA, TDOA, delay spread). By measuring signal propagation time and delay characteristics rather than arrival angles, the system achieves better precision in non-LOS environments where angle measurements become unreliable due to multipath effects.
3Ease of operation
If RSSI method is used for position determination, then position can be estimated from signal strength, but large errors occur due to radio wave shadowing and fast fading
Solution Approach 1:
The patent changes the measurement parameter from signal strength (RSSI) to signal propagation time (TOA, TDOA, delay spread). Time-based measurements are less susceptible to radio wave shadowing and fast fading effects that plague RSSI-based methods, as timing information is preserved even when signal amplitude fluctuates due to multipath interference.
Solution Approach 2:
The patent replaces the intensity-based measurement system (RSSI) with a time-based measurement system (TOA, TDOA). This substitution transforms the measurement from detecting signal amplitude (analogous to mechanical intensity detection) to detecting signal arrival time, which is more robust against environmental interference.
4Productivity
If TOA and TDOA methods are used for position determination, then relatively frequent use is achieved, but precision degrades because delay tap selection becomes ambiguous when spread time delay taps have random sizes
Solution Approach 1:
The patent changes from selecting individual delay taps to measuring the overall delay spread distribution. Instead of trying to identify a single dominant delay tap (which is ambiguous when multiple taps have similar magnitudes), the system measures the spread of delays across multiple taps, providing a more robust and precise position determination metric.
Solution Approach 2:
The patent transitions from one-dimensional delay tap magnitude selection to two-dimensional delay spread analysis. By considering the distribution and spread of delays across multiple taps rather than selecting a single tap based on magnitude, the system adds a dimensional aspect to the measurement that resolves the ambiguity of tap selection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of wireless position determination, enabling more precise location services even in environments where traditional GPS is ineffective, thereby activating various position-based services.
Implementation Method 1
measuring a propagation delay tap of a signal received from a transmitting end through a channel
Implementation Method 2
extracting delay spread information having various forms based on the propagation delay tap; obtaining a distance between transmission and reception ends based on the delay spread information
Data Source
AI summary
Provided is a wireless position determining method and apparatus. The wireless position determining includes: a measuring unit that measures a propagation delay tap of a signal received from a transmitting end through a channel; and extractor that extracts delay spread information having various forms based on the propagation delay tap; and an obtaining and calculating unit that obtains a distance between transmission and reception ends based on the delay spread information and calculates a position of a receiving end based on the obtained distance between the transmission and reception ends.