LTE Mobile Terminal Positioning via Uplink SRS Measurement
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Solution Overview
Problem
Current positioning technologies in LTE systems, such as A-GPS, OTDOA, and CellId + RTT, require additional devices or network coordination, and often fail to provide accurate location information, especially with CellId + RTT offering positioning accuracy greater than 500 meters, which is insufficient for most users.
Innovation Solution
A method and system that uses SRS measurement by a mobile terminal sent to a serving cell/NodeB and neighboring cells/NodeBs, where resource reservation notifications are sent to reserve measurement resources, allowing the mobile terminal to be accurately positioned without additional devices or network coordination, using received signal strength indicators and timing advances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If A-GPS positioning is used, then positioning accuracy is improved, but the wireless terminal requires additional GPS receiver hardware and must be able to face three satellites simultaneously
Solution Approach 1:
The patent extracts the positioning function from the terminal device and relocates it to the network side. The terminal only needs to send uplink reference signals, while the network side performs the complete positioning calculation process, eliminating the need for GPS receivers and complex terminal capabilities.
Solution Approach 2:
The network side acts as an intermediary between the terminal and the positioning function. Instead of the terminal directly performing positioning operations or requiring GPS hardware, the network side mediates the process by receiving uplink signals and calculating position information.
2Measurement precision
If OTDOA positioning is used, then positioning accuracy is improved, but the wireless terminal must support OTDOA measurement capability
Solution Approach 1:
The patent extracts the positioning measurement and calculation functions from the terminal and relocates them to the network side. The terminal only transmits uplink reference signals, while all positioning measurements and calculations are performed by the network, eliminating the need for OTDOA measurement support in the terminal.
3Measurement precision
If CellId + RTT positioning is used, then positioning accuracy is improved from CellId alone, but the positioning accuracy is still greater than 500 meters which is insufficient for most users
Solution Approach 1:
The patent changes the measurement parameters from downlink-based CellId and RTT measurements to uplink-based SRS signal measurements. By utilizing uplink reference signals and performing measurements at the network side, the system achieves much higher positioning accuracy that satisfies user requirements.
4Ease of operation
If existing positioning methods are used, then positioning service is provided, but additional devices or network coordination are required which increases system complexity
Solution Approach 1:
The network side performs positioning measurements and calculations autonomously using uplink reference signals from the terminal. This self-service approach at the network side eliminates the need for complex coordination with multiple network entities or additional positioning devices, simplifying the overall system while maintaining service availability.
Data Source
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AI summary
Provided is a method for positioning a mobile terminal in an LTE system, wherein the method comprises: a serving cell/base station sends respectively resource reservation notification messages to multiple neighbouring cells/base stations thereof, to notify the neighbouring cells/base stations to reserve measurement resources for SRS measurement of a mobile terminal; the mobile terminal sends SRSs to the serving cell/base station and the neighbouring cells/base stations by using the measurement resources respectively, so that the serving cell/base station and the neighbouring cells/base stations perform SRS measurement; and the serving cell/base station positions the mobile terminal according to results of the SRS measurement. Also provided is a corresponding system. By means of the solution provided in the present invention, the mobile terminal may be accurately positioned without adding any device, without coordination of the network side, and without any additional network device, and the mobile terminal does not need to meet any extra functional requirement.