Radio Environment Model Construction for Wireless Location
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Solution Overview
Problem
Accurate location of mobile terminals in wireless communication systems is challenging due to dynamic and random changes in the propagation environment, requiring a technique that is low-cost, non-invasive, and based on actual signal strength measurements rather than assumptions.
Innovation Solution
A system that uses passive receivers with directional antennas to measure signal strength and timing information from multiple receivers, combined with a database of terrestrial features to refine location estimates, employing techniques like TOA, TDOA, and ray tracing to determine the location of mobile devices with high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive receivers with directional antennas are used to measure signal strength and timing information, then location precision is improved, but device complexity increases
Solution Approach 1:
The system segments the location determination task by using multiple passive receivers distributed in the environment, each performing simple signal strength and timing measurements. The complex processing is divided among multiple simple devices rather than requiring one complex device, achieving high location precision through distributed measurement.
Solution Approach 2:
The patent introduces an intermediary processing system that receives measurements from multiple passive receivers and performs the complex location calculation using TOA, TDOA, and ray tracing methods. This intermediary handles the computational complexity while the passive receivers remain simple measurement devices.
2Measurement precision
If multiple receivers with directional antennas are deployed, then location accuracy is improved, but the cost and infrastructure requirements increase
Solution Approach 1:
The passive receivers utilize existing wireless communication infrastructure and standard signal processing capabilities to perform location measurements. The system leverages the existing network's signal transmission and reception mechanisms, allowing the infrastructure to serve dual purposes: communication and location measurement, thereby reducing additional cost requirements.
Solution Approach 2:
The patent makes the wireless communication infrastructure universal by enabling it to perform both its primary communication function and the secondary location measurement function. The same receivers and signals used for normal communication operations are also utilized for location determination, eliminating the need for dedicated specialized equipment.
3Reliability
If the system uses actual signal strength measurements from multiple receivers, then reliability of location determination is improved, but the system complexity and processing requirements increase
Solution Approach 1:
The system performs preliminary measurements of signal strength and timing information at multiple receivers before final location determination. These preliminary measurements are collected and stored, then processed using TOA, TDOA, and ray tracing methods to produce reliable location estimates. The preliminary action allows for comprehensive data collection that improves reliability.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously measures signal characteristics, compares them against expected propagation models, and adjusts location calculations accordingly. The ray tracing method provides feedback by modeling signal paths through the environment and comparing predicted versus actual measurements, improving reliability through iterative refinement.
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
The system achieves precise location determination of mobile devices with reduced errors, requiring minimal modification to existing hardware and infrastructure, and is capable of handling dynamic and complex propagation environments.
Implementation Method 1
passive receivers with directional antennas to measure signal strength and timing information from multiple receivers
Implementation Method 2
employing techniques like TOA, TDOA, and ray tracing to determine the location of mobile devices with high precision
Data Source
AI summary
A system and method for constructing a signal propagation model in a wireless communication system such as a cellular system based on at least one received wireless signal correlated to a geographic location.