Scheduling-Offset Assistance Data for Accurate NTN Positioning
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Solution Overview
Problem
Existing wireless communication systems, particularly 5G NR, face challenges in accurately determining the position of user equipment (UE) in non-terrestrial networks (NTN) due to varying satellite positions and timing uncertainties, which affect the precision of positioning reference signals and angle measurements.
Innovation Solution
The system enhances UE positioning in NTN by providing assistance data (AD) that includes expected RSTD values, compensation factors, uncertainty values, and angle measurements associated with scheduling offsets, allowing the UE to adjust communication parameters based on time and satellite positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If assistance data is provided without scheduling offset adjustments, then the system complexity is reduced, but timing precision and positioning accuracy deteriorate due to satellite motion and timing uncertainties
Solution Approach 1:
The patent applies preliminary action by pre-calculating and providing scheduling offset adjustments in the assistance data before the actual positioning measurement takes place. The location server computes expected RSTD values, compensation factors, and uncertainty values that account for satellite motion and timing uncertainties in advance, allowing the UE to apply these corrections during positioning without real-time computation complexity.
Solution Approach 2:
The patent uses an intermediary approach by introducing compensation factors and scheduling offset adjustments as intermediate parameters that mediate between the raw assistance data and the final positioning measurement. These intermediate values bridge the gap between the moving satellite positions and the timing-critical positioning measurements, enabling accurate positioning without direct real-time tracking complexity at the UE.
2Measurement precision
If assistance data includes multiple sets of parameters for different time durations, then positioning accuracy is improved, but the size and complexity of assistance data increases
Solution Approach 1:
The patent applies segmentation by dividing the assistance data into multiple parameter sets, each corresponding to a specific time duration or satellite orbital segment. Instead of providing one large continuous dataset, the assistance data is segmented into manageable chunks that can be independently processed and applied based on the current satellite position and time, reducing the overall data burden while maintaining continuous positioning accuracy.
3Measurement precision
If the system uses traditional positioning methods without scheduling offset considerations, then the implementation is simpler, but positioning accuracy deteriorates due to timing uncertainties from satellite motion
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting timing-related parameters (RSTD expectations, compensation factors, uncertainty values) based on satellite orbital parameters and scheduling offsets. Instead of using fixed positioning parameters, the system changes these parameters according to the satellite's motion state and the specific timing of the positioning measurement, thereby maintaining high accuracy without requiring complex real-time tracking algorithms at the UE.
Data Source
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AI summary
Aspects presented herein may enable a network entity to associate one or more positioning related parameters between a UE and an NTN base station with a scheduling offset, a position of the NTN base station, and/or a time. In one aspect, a network entity identifies a scheduling offset that is associated with an NTN base station. The network entity transmits, to a UE communicating with the NTN base station, one or more of: a set of expected RSTD values associated with the NTN base station, a set of compensation factors associated with the set of expected RSTD values, a set of uncertainty values associated with the set of expected RSTD values, a set of expected DL-AoD value s/uncertainties associated with the NTN base station, or a set of expected AoA value s/uncertainties associated with the NTN base station, where one or more of these parameters are derived based on the scheduling offset.