Double Differential Carrier Phase Positioning for UE Location
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Solution Overview
Problem
Current UE-based positioning methods, particularly in NR systems, face challenges in achieving high accuracy due to limitations in carrier phase positioning techniques, such as clock errors and phase coherency issues.
Innovation Solution
The implementation of a double differential operation using single difference carrier phase measurements from a positioning reference unit (PRU) and a target UE, which cancels out clock errors and improves positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If carrier phase measurements are used for UE-based positioning, then positioning accuracy is improved, but clock errors and phase coherency issues worsen the measurement reliability
Solution Approach 1:
The patent introduces positioning reference units (PRUs) as intermediary devices that perform carrier phase measurements on positioning reference signals. These PRUs act as mediators between the target UE and the positioning system, collecting measurements from multiple TRPs and providing them to the LMF for processing. This intermediary approach allows the system to benefit from carrier phase precision while mitigating the impact of clock errors through differential operations performed by the LMF using measurements from multiple reference units.
2Measurement precision
If single difference carrier phase measurements are performed by positioning reference units, then positioning accuracy is enhanced, but the system complexity increases due to double differential operations
Solution Approach 1:
The patent segments the positioning system into distinct functional components: target UEs, positioning reference units (PRUs), transmission reception points (TRPs), and location management function (LMF). Each segment performs specific tasks - PRUs perform single difference carrier phase measurements on signals from multiple TRPs, while the LMF performs double differential operations by comparing measurements from multiple PRUs. This segmentation distributes the computational complexity across multiple entities rather than concentrating it in one device, making the overall system more manageable despite the sophisticated algorithms required.
3Reliability
If multiple positioning reference units are used for double differential operation, then clock errors are mitigated, but the quantity of measurement data increases
Solution Approach 1:
The patent implements a feedback mechanism where the LMF collects carrier phase measurements from multiple positioning reference units, performs double differential operations to eliminate clock errors, and uses these processed measurements to calculate precise location estimates for target UEs. The system feedback loop involves the LMF requesting specific measurements from PRUs based on target UE location requirements, receiving the measurements, processing them through differential operations that cancel out clock errors, and generating location estimates that are fed back to the network for positioning services.
Data Source
AI summary
An apparatus, for example a target UE, may be configured to: request at least one single difference carrier phase measurement of at least one positioning reference signal, wherein the at least one single difference carrier phase measurement is performed with at least one positioning reference unit; transmit an indication of a set of time-stamps for measurement of the at least one positioning reference signal; receive first measurement data for the at least one positioning reference signal, wherein the first measurement data comprises, at least, the at least one single difference carrier phase measurement measured with reference to the set of time-stamps; and determine a location estimation of the apparatus, comprising performing a double differential operation based, at least partially, on the first measurement data and second measurement data.