NTN Uplink Timing Advance for Stable Beam Switching
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Solution Overview
Problem
In non-terrestrial network (NTN) communication, beam switching causes inaccurate determination of differential timing advance, leading to uplink timing deviation and interruption due to the terminal's inability to learn the accurate differential timing advance after beam switching.
Innovation Solution
A communication method where a network device provides delay compensation parameters to the terminal to determine the differential timing advance for the target beam, allowing the terminal to perform timing advance adjustment and maintain uplink continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam switching is performed in NTN communication, then the terminal can maintain connection with the satellite, but the differential timing advance becomes inaccurate causing uplink timing deviation
Solution Approach 1:
The network device pre-calculates and provides the differential timing advance value to the terminal before beam switching occurs. This allows the terminal to prepare the correct timing advance adjustment in advance, ensuring accurate uplink timing is maintained after beam switching without interruption.
Solution Approach 2:
The network device acts as an intermediary that calculates the differential timing advance based on its knowledge of satellite position and beam configuration, then provides this calculated value to the terminal. This mediator approach allows the terminal to obtain accurate timing advance information without needing to independently calculate it, resolving the measurement precision issue.
2Device complexity
If the terminal independently determines timing advance after beam switching, then device complexity is reduced, but uplink timing accuracy deteriorates
Solution Approach 1:
The network device serves as an intermediary that performs the complex calculation of differential timing advance and provides the result to the terminal. This transfers the computational burden from the terminal to the network device, maintaining timing accuracy while keeping terminal complexity low.
Solution Approach 2:
The network device calculates the differential timing advance parameter based on changes in satellite position and beam configuration, then provides this parameter to the terminal. This approach allows the terminal to simply apply the provided parameter without performing complex calculations, balancing accuracy and complexity.
Data Source
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AI summary
This application provides a communication method and apparatus, to improve stability of an uplink in non-terrestrial network (non-terrestrial network, NTN) communication. In this application, a terminal may obtain, from a currently accessed network device, a delay compensation parameter corresponding to a target beam that is about to be accessed, and the terminal determines, based on a full timing advance and the delay compensation parameter corresponding to the target beam, a differential timing advance corresponding to the target beam, to perform delay compensation and initiate uplink random access on the target beam. Therefore, continuity of an uplink can be maintained before and after beam switching, to improve communication reliability of the uplink.