RSTD Measurement Offset Compensation for NTN Positioning
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Solution Overview
Problem
Current techniques for providing assistance data and reporting reference signal time difference (RSTD) measurements in Non-Terrestrial Network (NTN) positioning are inadequate, failing to account for signal delays and uncertainties, which hinders accurate positioning of user equipment (UE).
Innovation Solution
The method involves modifying RSTD reporting to include an offset or subframe duration compensation in RSTD measurement information, allowing the location server to determine the UE's position more accurately by accounting for signal delays in NTN scenarios, using enhanced definitions and signaling for Expected RSTD and RSTD uncertainty, and modified reporting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current RSTD measurement techniques are used in NTN positioning, then the positioning process is simple, but positioning accuracy deteriorates due to unaccounted signal delays
Solution Approach 1:
The patent applies preliminary action by providing assistance data containing expected RSTD values and uncertainty parameters to the UE before the actual RSTD measurement is performed. This allows the UE to pre-compensate for known signal delays and propagation effects specific to NTN scenarios, improving measurement accuracy without adding complex real-time processing during the positioning measurement itself
Solution Approach 2:
The patent changes the parameters used in RSTD measurements by introducing NTN-specific parameters such as expected RSTD, RSTD uncertainty, and subframe duration offsets. These parameter modifications allow the measurement system to account for the unique characteristics of non-terrestrial networks, including longer propagation delays and timing uncertainties, thereby improving positioning accuracy in NTN environments
2Reliability
If standard RSTD reporting is used, then reporting is straightforward, but it fails to account for NTN-specific delays and uncertainties
Solution Approach 1:
The patent implements feedback by having the UE report not only the measured RSTD value but also associated uncertainty parameters and offset information back to the location server. This feedback mechanism allows the location server to refine positioning estimates by considering both the measured values and their uncertainties, improving the reliability of NTN positioning while preserving critical signal delay information through structured reporting
Solution Approach 2:
The patent uses assistance data as an intermediary that carries NTN-specific timing information, expected RSTD values, and uncertainty parameters from the location server to the UE. This intermediary structure enables the transmission of complex timing compensation information without requiring direct modification of the RSTD measurement process itself, thereby maintaining reporting simplicity while accounting for NTN-specific delays
3Ease of manufacture
If NTN positioning is implemented without modified RSTD reporting, then implementation is simpler, but positioning accuracy deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the positioning system into distinct functional components: the location server that provides assistance data, the UE that performs measurements and reporting, and the network that handles positioning calculations. This segmentation allows each component to be implemented independently with standard interfaces, maintaining ease of implementation while enabling accurate NTN positioning through specialized assistance data and reporting mechanisms
Data Source
AI summary
In some implementations, a location server may, in a positioning session between the location server and a user equipment (UE): receive, from the UE, a report message comprising reference signal time difference (RSTD) measurement information of an RSTD measurement, performed by the UE, of radio frequency (RF) signals, wherein: at least one RF signal of the RF signals is transmitted by an NTN Next Generation Radio Access Network (NG-RAN) node, and the RSTD measurement information comprises an offset to compensate for a delay in the at least one RF signal. The location server may determine a position of the UE based at least in part on the RSTD measurement information.