Frequency Offset Compensation in Non-Terrestrial Satellite Networks
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Solution Overview
Problem
Existing frequency offset compensation processes in terrestrial communication systems are ineffective in non-terrestrial networks, particularly for communication satellites moving at high speeds, leading to interference and reduced receiving performance due to rapid Doppler frequency shifts.
Innovation Solution
A method involving a terminal and network device collaboration, where the terminal compensates or precompensates frequencies based on downlink frequency offsets and receives uplink residual frequency offsets from the network device to calibrate compensation frequencies, effectively tracking and compensating for Doppler frequency shifts in satellite communication links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing frequency offset compensation process is used in non-terrestrial networks, then the process simplicity is maintained, but the receiving performance deteriorates due to ineffective tracking of rapid Doppler frequency shifts
Solution Approach 1:
The network device performs preliminary estimation of the uplink residual frequency offset and proactively sends this information to the terminal before the terminal needs to compensate for the frequency offset. This preliminary action allows the terminal to use the pre-estimated offset information, improving receiving performance without requiring the terminal to perform complex estimation calculations
Solution Approach 2:
The network device acts as an intermediary that estimates the uplink residual frequency offset and communicates it to the terminal. This intermediary approach allows the terminal to benefit from accurate frequency offset information without performing the estimation itself, resolving the contradiction between maintaining process simplicity and improving receiving performance
2Measurement precision
If terminal performs local estimation and compensation for Doppler frequency shift, then the processing speed is maintained, but the compensation accuracy deteriorates in non-terrestrial networks due to rapid frequency changes
Solution Approach 1:
The network device estimates the uplink residual frequency offset based on received uplink signals and sends this information back to the terminal as feedback. The terminal then uses this feedback information to calibrate its frequency compensation. This feedback mechanism ensures high estimation accuracy while reducing the time required for the terminal to perform independent estimation, as the network device's continuous monitoring and feedback provide real-time accurate offset information
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 improves communication quality by accurately compensating for frequency offsets in non-terrestrial networks, reducing interference and enhancing usability.
Implementation Method 1
When a mobile station moves in a direction at a constant speed, phase and frequency of a signal sent and/or received by the mobile station will change due to difference in a propagation path, and the change is generally called Doppler frequency shift. In a non-terrestrial network (NTN), communication satellites move at a high speed, which will generate a large Doppler frequency shift
Implementation Method 2
determining an uplink residual frequency offset corresponding to an uplink signal in response to detecting the uplink signal sent by a terminal
Data Source
AI summary
A method for compensating for and calibrating a frequency offset is performed by a terminal, and includes: compensating or precompensating a target frequency according to a downlink frequency offset; obtaining an uplink residual frequency offset sent by a network device, the uplink residual frequency offset corresponding to an uplink signal sent by the terminal; and calibrating a compensation frequency or a precompensation frequency for the target frequency according to the uplink residual frequency offset.