UE Positioning via Multi-Time Reference Signals in NTN
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Solution Overview
Problem
Existing methods for determining a user equipment (UE) position in non-terrestrial networks (NTN) face challenges due to the dynamic nature of satellite positioning, where timing advance (TA) is not accurately configured, leading to inaccuracies in location verification.
Innovation Solution
A method involving the UE receiving and reporting reference signals at multiple time instances, allowing the network to determine and verify the UE's position using time difference of arrival (TDOA) and round trip time (RTT) schemes, enhancing accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single satellite is used for positioning in NTN, then the system complexity is reduced and coverage is improved, but positioning accuracy deteriorates due to higher propagation delay and TA configuration challenges
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple reference signals (DL RSs and UL RSs) at multiple time instances before positioning determination. The network pre-arranges the timing and structure of these reference signals, allowing the UE to measure time differences without real-time complex calculations. This pre-arranged framework enables accurate positioning even with a single satellite by establishing known reference points in time.
Solution Approach 2:
The patent replaces traditional mechanical timing advance adjustment with a signal-processing-based solution. Instead of physically adjusting transmission timing based on UE position, the system uses measured time difference values from reference signals at multiple instances to calculate position. This substitution of physical timing adjustment with measurement-based calculation resolves the TA configuration challenge in single-satellite NTN positioning.
2Device complexity
If timing advance is configured based on common TA only, then device complexity is reduced, but positioning accuracy deteriorates due to lack of UE-specific timing adjustment
Solution Approach 1:
The patent implements feedback by having the UE measure and report time difference values (first value for DL RS reception times, second value for UL RS transmission times) back to the network. The network uses this feedback information, combined with known reference signal timing, to determine the UE's position. This feedback mechanism enables accurate positioning without requiring complex real-time TA adjustments, as the measured time differences directly inform position calculation.
Solution Approach 2:
The patent applies self-service by enabling the UE to autonomously measure time differences of received reference signals and determine its own position based on these measurements. The UE calculates the first value (reception time instances of DL RSs) and second value (transmission time instances of UL RSs) independently and reports them to the network, which then determines position. This self-measurement approach reduces network complexity while maintaining positioning accuracy.
3Measurement precision
If reference signals are transmitted at multiple time instances, then positioning accuracy is improved through TDOA and RTT schemes, but signal transmission time and latency increase
Solution Approach 1:
The patent applies periodic action by transmitting reference signals at multiple discrete time instances in a periodic or semi-periodic manner. The first group of DL RSs and second group of UL RSs are transmitted at predetermined time instances, creating multiple measurement opportunities. This periodic transmission provides sufficient data for accurate TDOA and RTT calculations while maintaining manageable transmission intervals that balance accuracy requirements with latency constraints.
Data Source
AI summary
A method and apparatus for determining UE's position are provided. The method may be performed by a UE. The method includes receiving a first signal indicating at least one of: a first DL RSs at multiple time instances, a second group of UL RSs at multiple time instances, or a third group of UL transmissions at multiple time instances upon receptions of a fourth group of DL transmissions at multiple time instances; receiving a second signal indicating to report at least one of: a first value associated with reception time instances of the first group of DL RSs, a second value associated with transmission time instances of the second group of UL RSs, or a third value associated with transmission time instances of the third group of UL transmissions; and reporting at least one of the first value, the second value, or the third value or determine the uplink transmission time instances for the second set of UL RS or for the third set of UL transmission.