Uplink Frequency Control for NTN Doppler Shift Correction
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Solution Overview
Problem
In radio communication systems, particularly in Non-Terrestrial Networks (NTNs) like satellite communications, uplink transmission efficiency is hindered by Doppler shifts caused by satellite movement, especially when non-GNSS terminals and GNSS terminals coexist, leading to difficulties in frequency correction and increased complexity for base station processing.
Innovation Solution
A method where a base station transmits frequency control information to terminals to adjust uplink frequencies, allowing both GNSS and non-GNSS terminals to correct Doppler shifts, with the base station determining frequency adjustment values based on satellite position, direction, and beam center, and terminals adjusting their frequencies accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency control information is transmitted to terminals for Doppler shift correction, then uplink transmission efficiency is improved, but base station processing complexity increases
Solution Approach 1:
The patent introduces frequency control information as an intermediary mechanism that mediates between the base station and terminals. The base station calculates frequency adjustment values based on satellite position and terminal location, then transmits these control information to terminals. This intermediary approach enables automated Doppler shift correction without requiring complex real-time processing at the base station during uplink reception, thus improving transmission efficiency while managing processing complexity.
Solution Approach 2:
The base station performs frequency adjustment calculations in advance based on satellite ephemeris data, terminal position information, and beam center coordinates. By pre-calculating frequency control information before uplink transmission occurs, the system prepares correction values proactively, eliminating the need for complex real-time frequency adjustment during the actual transmission process.
2Measurement precision
If separate frequency correction methods are used for GNSS and non-GNSS terminals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal frequency control mechanism where both GNSS and non-GNSS terminals receive frequency control information from the base station in a unified manner. The base station adapts its control information generation to account for different terminal types, but the terminals themselves follow the same reception and application process. This universal approach maintains measurement precision for both terminal types while avoiding the complexity of implementing separate correction algorithms at each terminal.
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 enables efficient uplink transmission by reducing Doppler shift influence, allowing multiplexing of signals from both types of terminals and reducing processing complexity at the base station, thereby enhancing overall communication efficiency.
Implementation Method 1
uplink transmission efficiency is hindered by Doppler shifts caused by satellite movement
Data Source
AI summary
The present invention improves transmission efficiency in wireless communication. In the present invention, a terminal comprises a reception circuit for receiving control information for adjusting an uplink transmission frequency, and a control circuit for controlling the transmission frequency on the basis of the control information.