NTN Positioning Using Uplink-Downlink Subframe Offset Alignment
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Solution Overview
Problem
Existing positioning methods for terminal devices in terrestrial networks are inadequate for non-terrestrial networks (NTN) due to larger coverage areas and propagation delays, necessitating improved location verification and positioning solutions.
Innovation Solution
A method and apparatus that utilize measurements of downlink and uplink positioning reference signals, including offsets and propagation delays, to determine the location of terminal devices in NTN scenarios, enhancing accuracy through frame number and subframe number alignment and reporting mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing positioning methods for terrestrial networks are used in NTN, then device complexity is reduced, but measurement precision deteriorates due to larger coverage areas and propagation delays
Solution Approach 1:
The positioning method is segmented into distinct measurement phases: downlink positioning reference signal measurement by terminal, uplink positioning reference signal measurement by network device, and location determination by location management function. Each segment handles specific aspects of positioning, allowing complex NTN positioning to be broken down into manageable terrestrial-compatible operations while maintaining accuracy through systematic measurement collection and processing
Solution Approach 2:
A location management function is introduced as an intermediary between terminal devices and network devices. This intermediary collects measurement results from both downlink and uplink positioning reference signals, processes the combined information, and determines terminal locations. The intermediary handles the complexity of integrating measurements across large NTN coverage areas, shielding terminal devices from complex positioning calculations while improving measurement precision through centralized processing
2Measurement precision
If frame number and subframe number alignment is implemented, then measurement precision improves, but device complexity increases due to additional offset reporting requirements
Solution Approach 1:
The system performs preliminary timing alignment by pre-defining frame numbers and subframe numbers for downlink and uplink positioning reference signals. Offset values between corresponding downlink and uplink subframes are pre-calculated and included in measurement reports before location determination. This preliminary timing synchronization establishes a consistent reference framework that improves measurement precision without requiring complex real-time calculations during positioning
Solution Approach 2:
The patent reports not only the essential measurement results but also additional timing information including frame numbers, subframe numbers, and offsets between downlink and uplink subframes. This excessive reporting of timing parameters provides redundant synchronization information that enhances measurement precision through multiple reference points, while the location management function processes only the necessary data for location determination, filtering out excess information
Data Source
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AI summary
This application provides a positioning method and a positioning apparatus for an NTN. The method includes: A first device determines a location of a terminal device with reference to a measurement result of an uplink positioning reference signal based on an offset, reported by the terminal device, between a start location of a subframe in which a downlink positioning reference signal is located and a start location of an uplink subframe that has a same frame number and a same subframe number as the subframe and that is closest to the subframe, or based on an offset, reported by the terminal device, between a start location of a subframe in which a downlink positioning reference signal is located and a start location of an uplink subframe in which the uplink positioning reference signal sent by the terminal device is located. Therefore, accuracy of the location of the terminal device is improved.