NTN Terminal Positioning with Redefined Rx-Tx Time Differences
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Solution Overview
Problem
In non-terrestrial networks (NTN), it is challenging to accurately estimate the location of a terminal (UE) due to the difficulty in capturing multiple TRPs, necessitating the use of methods like Multi-RTT, DL-TDOA, and UL-TDOA, which are defined in the same manner as in terrestrial networks, leading to inaccurate UE/gNB Rx-Tx time differences and DL-RSTD, UL-RTOA.
Innovation Solution
A terminal and base station system that receives and processes downlink and uplink reference signals via a non-terrestrial network, employing specific control mechanisms to estimate location information by defining UE/gNB Rx-Tx time differences and DL/UL-RTOA differently from terrestrial networks, using NTN-specific definitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE/gNB Rx-Tx time difference, DL-RSTD, and UL-RTOA are defined in the same manner as in the terrestrial network, then the positioning method can be uniformly applied, but the location information of the terminal cannot be appropriately estimated in NTN due to propagation delays and frame alignment issues
Solution Approach 1:
The patent applies local quality by introducing NTN-specific definitions for time difference parameters (UE Rx-Tx time difference, gNB Rx-Tx time difference, DL-RSTD, UL-RTOA) that differ from terrestrial network definitions. These localized adaptations account for the unique propagation characteristics and frame structures in NTN, allowing accurate positioning while maintaining uniform methodology within the NTN context.
Solution Approach 2:
The patent changes the parameters used for positioning by redefining time difference measurements specifically for NTN. The UE Rx-Tx time difference is defined as the difference between uplink transmission time and downlink reception time at the UE, while the gNB Rx-Tx time difference accounts for satellite relay delays. These parameter changes enable accurate location estimation despite the different propagation environment in NTN.
2Measurement precision
If multiple TRPs are used for positioning as in terrestrial networks, then positioning accuracy can be improved, but it becomes difficult to capture multiple TRPs in NTN due to satellite relay architecture
Solution Approach 1:
The patent applies universality by enabling a single TRP (satellite relay) to perform multiple functions that would normally require multiple TRPs in terrestrial networks. The single TRP in NTN provides both downlink positioning reference signals and uplink reception, and the patent defines measurement parameters that allow accurate positioning using this single multi-functional node, eliminating the need to capture multiple separate TRPs.
3Ease of manufacture
If terrestrial network positioning methods are applied to NTN, then the system can use existing protocols, but the propagation delays and frame alignment issues in NTN lead to inaccurate time difference measurements
Solution Approach 1:
The patent applies preliminary action by pre-defining NTN-specific parameter definitions and measurement procedures before actual positioning operations. The UE and gNB are configured with NTN-appropriate definitions for time difference parameters, and the network provides necessary assistance information in advance, allowing accurate measurements despite the different propagation characteristics of NTN compared to terrestrial networks.
Data Source
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AI summary
A terminal includes: a receiving unit that receives a downlink reference signal from a non-terrestrial network device via a non-terrestrial network; and a control unit that controls a report of a measurement result regarding the downlink reference signal in specific control of estimating location information of the terminal based on the downlink reference signal, wherein the control unit assumes information regarding the location information of the terminal with a definition different from a definition in a terrestrial network.