LTE Positioning Using Combined Downlink and Uplink Measurements
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Solution Overview
Problem
Current location determination methods in wireless communication networks, such as UMTS and LTE, face challenges in providing accurate positioning for mobile devices, especially in indoor environments and unsynchronized networks, and are costly due to the need for GPS chipsets and satellite dependence, with methods like OTDOA facing implementation hurdles and impacting network performance.
Innovation Solution
A method that combines downlink and uplink signal measurements, including OTDOA and E-CID techniques, to estimate the location of mobile devices in both synchronous and asynchronous networks, using observed positioning information and propagation delays to determine ranges and geographic locations, without requiring modifications to existing devices or infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS-based positioning is used, then location accuracy is improved, but device cost and manufacturing complexity increase due to GPS chipsets
Solution Approach 1:
The patent replaces GPS satellite-based positioning with a terrestrial wireless network-based positioning system. Instead of using GPS chipsets that communicate with satellites, the system uses base stations to transmit positioning signals and perform trilateration calculations, substituting a mechanical/space-based system with an electromagnetic/network-based system that leverages existing infrastructure.
Solution Approach 2:
The patent creates a terrestrial copy of the GPS positioning concept by implementing a network of base stations that emulate satellite positions and signal transmissions. The base stations transmit positioning signals similar to GPS satellites, allowing the mobile device to perform trilateration using terrestrial signals instead of satellite signals, thereby eliminating the need for GPS chipsets.
2Measurement precision
If OTDOA positioning method is used, then location accuracy is improved, but network performance deteriorates and implementation becomes more complex
Solution Approach 1:
The patent implements a simplified version of OTDOA by having base stations transmit positioning signals only during specific subframes dedicated to positioning, rather than continuous transmission. This partial action approach provides sufficient positioning data while reducing overall network signal overhead and maintaining network performance for other communications.
Solution Approach 2:
The patent segments the positioning function from general communication functions by dedicating specific subframes and resources exclusively to positioning signal transmission. This segmentation allows positioning operations to occur without interfering with regular data and voice traffic, thereby maintaining network performance while enabling accurate positioning.
3Measurement precision
If synchronized network positioning is used, then location accuracy is improved, but adaptability to asynchronous networks deteriorates
Solution Approach 1:
The patent changes the timing parameters of base station transmissions to accommodate both synchronized and asynchronous networks. The system adjusts signal transmission timing and incorporates timing advance calculations that work whether the network is globally synchronized or operates with independent base station clocks, thereby maintaining positioning accuracy across different network synchronization states.
Solution Approach 2:
The patent creates a universal positioning method that functions in both synchronized and asynchronous network environments. The base station positioning signals are designed to be compatible with different network synchronization states, allowing the same positioning infrastructure to serve diverse network types without requiring separate systems for synchronized and asynchronous operations.
4Measurement precision
If additional positioning infrastructure is deployed, then location accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The patent makes existing base stations perform dual functions: regular communication and positioning signal transmission. By enabling base stations to serve both purposes simultaneously, the system achieves accurate positioning without adding dedicated positioning infrastructure, thereby reducing system complexity and deployment costs while maintaining positioning functionality.
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
This approach enhances location accuracy and reduces costs by leveraging existing network infrastructure, improving compliance with regulations like E-911 and providing effective Location-Based Services without relying on satellite networks or additional hardware, while minimizing disruptions to network operations.
Implementation Method 1
a propagation delay determined between a node serving the mobile device and the mobile device as a function of the received uplink positioning information
Implementation Method 2
combines downlink and uplink signal measurements, including OTDOA and E-CID techniques, to estimate the location of mobile devices
Data Source
AI summary
A method of determining the location of a mobile device in a communications network having a plurality of nodes, one of the plural nodes serving the device. Observed positioning measurements for a mobile device may be received from the serving node and uplink enhanced cell identification (E-CID) positioning measurements received from the mobile device. One or more ranges between ones of the plural nodes and the mobile device may then be determined as a function of the received observed positioning measurements and the received uplink E-CID positioning measurements. A geographic location of the mobile device may then be estimated as a function the determined one or more ranges.