NTN Neighbor Cell Measurement via Terminal Position Criteria
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Solution Overview
Problem
In non-terrestrial network (NTN) systems, existing methods for neighbor cell measurement face challenges due to the difficulty in configuring appropriate RSRP thresholds and the potential for measurement errors, leading to inappropriate power consumption and increased RRC re-establishment time.
Innovation Solution
A method for neighbor cell measurement in NTN systems, where a terminal initiates measurement based on whether the distance and/or distance variation between the terminal and a serving cell reference point meets a terminal position-based evaluation criterion, configured by the network device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RSRP threshold-based measurement is used in NTN systems, then measurement configuration is simplified, but measurement precision deteriorates due to difficulty in configuring appropriate thresholds and potential measurement errors
Solution Approach 1:
The patent changes the measurement trigger parameter from RSRP (signal strength) to distance-based criteria (terminal position relative to serving cell reference point). This parameter change allows the network to configure distance thresholds instead of RSRP thresholds, which are easier to determine accurately in NTN environments where signal strength varies due to satellite motion and geometry. The distance-based approach directly addresses the measurement precision problem by using geometric relationships that are more stable and predictable than signal strength in satellite communications.
2Extent of automation
If neighbor cell measurement is initiated based on RSRP threshold, then measurement triggering is automated, but power consumption increases due to inappropriate measurement initiation
Solution Approach 1:
The patent changes the triggering parameter from RSRP to distance-based criteria, which enables more accurate prediction of when measurements are actually needed. By monitoring terminal position and comparing it to the serving cell reference point, the system can automatically trigger measurements only when the terminal approaches cell boundaries, rather than continuously or based on signal strength fluctuations. This maintains automation while significantly reducing unnecessary measurements and associated power consumption.
Solution Approach 2:
The system performs preliminary position-based evaluation before initiating measurements. By continuously tracking terminal position relative to the serving cell reference point and evaluating distance criteria in advance, the system prepares measurement triggering conditions without actually performing measurements until necessary. This preliminary action allows the system to automate measurement triggering while avoiding the energy waste of performing measurements when they are not needed.
3Device complexity
If RSRP-based measurement triggering is used, then measurement initiation is simplified, but RRC re-establishment time increases due to measurement errors and inappropriate triggering
Solution Approach 1:
The patent changes the measurement triggering parameter from RSRP to distance-based criteria, which provides more reliable and accurate triggers for neighbor cell measurements. By using terminal position relative to serving cell reference point, the system ensures measurements are triggered at the appropriate moments when cell reselection is actually needed, rather than based on signal strength variations that may not correlate with actual cell boundary crossings. This reduces measurement errors and ensures timely cell reselection, directly reducing RRC re-establishment time.
4Measurement precision
If distance-based evaluation criterion is used, then measurement precision is improved, but device complexity increases due to position tracking requirements
Solution Approach 1:
The patent introduces the serving cell reference point as an intermediary reference for distance-based evaluation. Instead of requiring complex multi-dimensional position tracking and real-time geometric calculations, the system uses the reference point (which could be the cell center or another fixed location) as a mediator. The terminal position is evaluated relative to this reference point, simplifying the calculation to basic distance metrics. This intermediary approach maintains high measurement precision while significantly reducing the computational complexity of position tracking and evaluation.
Data Source
AI summary
Provided is a method for neighbor cell measurement in an NTN. The method is applicable to a terminal. The method includes: initiating measurement of neighbor cells based on whether at least one of a distance or a distance variation between the terminal and a serving cell reference point meets a terminal position-based evaluation criterion.