Frequency-Domain PRS Search Windows for NTN Doppler Shifts
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately determining the location of non-terrestrial transmission-reception points (NT-TRPs) due to Doppler frequency shifts, which affect the precision of positioning reference signals (PRS) in non-terrestrial networks (NTNs).
Innovation Solution
The method involves determining a frequency domain search window based on expected Doppler frequency shift offset and uncertainty for PRS resources associated with NT-TRPs, allowing for precise measurement of these signals during positioning sessions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler frequency shift compensation is applied for NTN positioning, then positioning accuracy is improved, but system complexity increases due to the need to determine and search frequency domain windows
Solution Approach 1:
The patent applies preliminary action by pre-determining the frequency domain search window based on expected Doppler frequency shift offsets and uncertainties before actual positioning measurements. The network entity calculates the search window parameters in advance and provides them to the UE, which then uses this pre-configured window for PRS measurements, avoiding real-time complex calculations during positioning sessions
Solution Approach 2:
The patent utilizes parameter changes by adjusting the frequency domain search window parameters (center frequency and bandwidth) according to the expected Doppler shift characteristics of NTN signals. The search window is dynamically configured based on satellite velocity, orbital parameters, and frequency offset uncertainties, allowing the system to adapt to varying Doppler conditions without requiring complex real-time processing
2Reliability
If frequency domain search window is determined based on Doppler uncertainty, then measurement reliability is improved, but information processing requirements increase
Solution Approach 1:
The patent applies the skipping principle by directly determining the frequency domain search window using closed-form calculations based on satellite orbital parameters and expected Doppler shifts. Instead of performing iterative searches or extensive signal processing to estimate Doppler characteristics, the method rapidly calculates the search window parameters using pre-computed satellite ephemeris data and transmits them to the UE for immediate use in PRS measurements
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 the accuracy of positioning in NTN environments by accounting for Doppler effects, improving the precision of location determination in non-terrestrial networks.
Implementation Method 1
determining a frequency domain search window corresponding to an expected Doppler frequency shift offset and an expected Doppler frequency shift offset uncertainty for at least one positioning reference signal (PRS) resource associated with at least one non-terrestrial transmission-reception point (NT-TRP)
Data Source
AI summary
Disclosed are techniques for wireless positioning. In an aspect, a network entity may determine a frequency domain search window corresponding to an expected Doppler frequency shift offset and an expected Doppler frequency shift offset uncertainty for at least one positioning reference signal (PRS) resource associated with at least one non-terrestrial transmission-reception point (NT-TRP) for a positioning session. The network entity may measure the at least one PRS resource in the frequency domain search window during the positioning session.