UMTS Ranging via Uplink Downlink Timing
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Solution Overview
Problem
Existing wireless communication systems face limitations in accurately determining the location of mobile stations, particularly in urban environments with RF fading, and require significant hardware modifications or upgrades to meet Phase II E-911 requirements, which increases costs and complexity.
Innovation Solution
A method and system that utilize measured downlink timing of a serving cell site combined with measured uplink time of arrival to derive a range estimate, allowing for the calculation of a mobile station's location without the need for three or more separate base stations and minimizing hardware changes, thereby maximizing location-related measurements and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional location methods (GPS, triangulation, TDOA) are used to achieve accurate location determination, then location accuracy is improved, but device complexity and infrastructure requirements increase significantly
Solution Approach 1:
The patent extracts the location determination capability from complex external systems (GPS receivers, multiple base stations) and implements it within the existing UMTS network infrastructure using only the serving base station and mobile station, thereby reducing infrastructure complexity while maintaining location accuracy
Solution Approach 2:
The mobile station performs autonomous location determination by measuring uplink timing and processing downlink timing information from its serving base station, eliminating the need for external GPS infrastructure or coordination with multiple base stations, thus reducing overall system complexity
2Measurement precision
If Phase II E-911 requirements are met using external methods like GPS, then location accuracy is improved, but manufacturing cost increases due to hardware modifications
Solution Approach 1:
The patent makes the existing UMTS uplink and downlink timing measurement mechanisms serve dual purposes: traditional network synchronization and location determination, eliminating the need for separate GPS hardware and reducing manufacturing costs while meeting Phase II E-911 requirements
Solution Approach 2:
The patent uses the existing timing synchronization infrastructure already present in UMTS networks and repurposes it for location determination, creating a cost-effective solution that copies the functionality of expensive GPS hardware using affordable existing network elements
3Measurement precision
If three or more separate base stations are used for triangulation or TDOA methods, then location accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the location determination function into independent timing measurements (uplink timing at mobile station, downlink timing at base station) that can be performed separately and combined, eliminating the need for multiple base stations while maintaining accuracy through mathematical processing of timing differences
Data Source
AI summary
A method and system for determining an approximate range from a location measurement unit to a mobile device. An uplink signal from the mobile device is received by the location measurement unit, and an uplink frame marker is determined from the uplink signal. A downlink signal is received at the location measurement unit from a base station serving the mobile device, and a downlink slot marker is determined from the downlink signal. A round trip propagation delay is determined based upon the uplink frame marker and the downlink slot marker, and an approximate range from the location measurement unit to the mobile device is determined as a function of the round trip propagation delay.