Doppler Shift Correction in Non-Terrestrial 5G Networks
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Solution Overview
Problem
In 5G non-terrestrial networks, existing technologies face challenges in accurately measuring and correcting Doppler shifts between user equipment (UE) and satellites, leading to potential signal frequency mismatches and communication disruptions due to motion-induced frequency shifts.
Innovation Solution
A method involving user equipment (UE) measuring downlink signals, estimating Doppler shifts, and transmitting these measurements to satellites for correction, which then apply the corrections to uplink signals, ensuring synchronized frequency across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Doppler shift measurement and correction methods are implemented in 5G non-terrestrial networks, then communication reliability is improved, but device complexity increases due to additional measurement and correction mechanisms
Solution Approach 1:
The user equipment autonomously performs Doppler shift measurements on downlink signals and generates correction values without requiring complex network-side intervention. The UE self-services by measuring, computing, and applying corrections while exchanging necessary information with the satellite, thereby improving reliability without proportionally increasing overall system complexity
Solution Approach 2:
The system implements a feedback mechanism where the UE measures Doppler shifts, transmits measurement results to the satellite, receives correction values, and applies them to uplink signals. This closed-loop feedback process ensures continuous adaptation to motion-induced frequency shifts, enhancing communication reliability in dynamic satellite environments
2Reliability
If Doppler shift correction is applied to uplink signals, then signal quality is improved, but processing time is increased due to measurement and correction steps
Solution Approach 1:
The user equipment performs Doppler shift measurements on downlink signals in advance before uplink transmission. By computing correction values preliminarily based on downlink measurements and applying them proactively to uplink signals, the system reduces signal quality degradation without requiring extensive real-time processing during critical transmission moments
Solution Approach 2:
The system accelerates the Doppler correction process by efficiently measuring downlink signals and rapidly computing correction values. The UE expediently transmits measurement results and receives corrections in a streamlined manner, minimizing the time overhead introduced by the additional measurement and correction steps while maintaining signal quality
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 enhances communication reliability by accurately accounting for motion-induced frequency shifts, improving signal quality and reducing errors in 5G non-terrestrial networks.
Implementation Method 1
The Doppler shift includes a frequency shift between a first frequency related to the downlink (DL) signal transmitted from the satellite, and a second frequency related to the DL signal received by the user equipment (UE), due to motion of the UE
Data Source
AI summary
Apparatus and methods are provided that perform Doppler shift measurements and correction between a user equipment (UE) and a satellite in a Non-Terrestrial Network (NTN). In one embodiment, the UE performs measurements to compute the Doppler shift, and transmits the Doppler shift to the satellite. In another embodiment, the satellite measures the Doppler shift for each UE, and transmits the Doppler shifts to each UE.