Terminal Device Doppler Offset Assistance for NTN Frequency Measurement
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Solution Overview
Problem
In Non Terrestrial Network (NTN) systems, the high-speed movement of satellites causes discrepancies between the frequency indicated by the network and the actual frequency needed for UE measurements or downlink synchronization, leading to increased blind search operations and complexity for terminal devices.
Innovation Solution
The method involves a terminal device receiving Doppler shift assistance information from a network device, which is used to determine the actual frequency to be measured or accessed during NR measurements or downlink synchronization, thereby reducing blind search operations and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the terminal device uses the frequency indicated by the network for measurements or downlink synchronization in NTN systems, then the network can provide frequency information to the terminal device, but the actual frequency needed may be different due to satellite high-speed movement, causing the terminal device to perform a large number of blind search operations and increasing terminal device complexity
Solution Approach 1:
The network device performs preliminary calculations to determine the actual frequency offset caused by satellite movement before the terminal device needs to measure or synchronize. The network device sends this pre-calculated frequency offset information to the terminal device, allowing the terminal device to directly apply the correct frequency without performing blind searches, thereby reducing terminal device complexity while maintaining frequency information accuracy
Solution Approach 2:
The network device acts as an intermediary that calculates and provides frequency offset information to the terminal device. Instead of the terminal device independently determining the frequency offset through complex blind searches, the network device intermediates by providing the calculated offset, thereby reducing the computational burden and complexity of the terminal device while ensuring accurate frequency information
2Reliability
If the terminal device performs blind search operations to find the actual frequency, then the terminal device can potentially find the correct frequency, but the number of blind search operations increases significantly, consuming more time and resources
Solution Approach 1:
The network device performs preliminary calculations to determine the actual frequency offset before the terminal device needs to measure or synchronize. By sending this pre-calculated offset information to the terminal device, the terminal device can directly determine the correct frequency without performing multiple blind search operations, thereby maintaining frequency determination reliability while significantly reducing the time and resources consumed
3Ease of operation
If the network device provides frequency information to the terminal device, then the terminal device can perform measurements and synchronization, but the high-speed movement of satellites causes the indicated frequency to differ from the actual frequency needed, reducing measurement and synchronization accuracy
Solution Approach 1:
The network device calculates and provides frequency offset information that accounts for satellite movement parameters. The terminal device applies this offset to the indicated frequency to obtain the actual frequency needed for measurements and synchronization. This parameter adjustment ensures that the terminal device can easily configure frequencies while maintaining measurement precision despite satellite high-speed movement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows the terminal device to accurately determine the necessary frequencies, reducing blind search operations and complexity, and enhancing the efficiency of frequency measurement and synchronization in NTN systems.
Implementation Method 1
the high-speed movement of satellites causes discrepancies between the frequency indicated by the network and the actual frequency needed for UE measurements or downlink synchronization
Data Source
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AI summary
Embodiments of the present application provide methods for determining a frequency point, a terminal device, and a network device. A method includes: a terminal device receives Doppler frequency offset assistance information; and the Doppler frequency offset assistance information is used to determine an actual frequency point to be measured or an actual frequency point of downlink synchronization of a target cell. In the embodiments of the present application, the amount of blind retrieval operations of a terminal device can be reduced, and the complexity of the terminal device is reduced.