Non-Terrestrial Uplink Phase Rotation for Timing Compensation
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Solution Overview
Problem
Non-terrestrial networks experience significant timing errors due to large round-trip times and satellite movement, leading to performance degradation in wireless communications.
Innovation Solution
A method and apparatus for user equipment (UE) that modulates a symbol stream onto subcarriers, applies phase rotation in the frequency domain, and transforms the signal to the time domain to compensate for timing errors, reducing synchronization issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional uplink transmission is used in non-terrestrial networks, then the system can operate with standard timing procedures, but significant timing errors occur due to large round-trip times and satellite movement
Solution Approach 1:
The patent applies preliminary action by calculating and applying phase rotation to subcarriers before uplink transmission based on predicted satellite position and timing error compensation values. This pre-compensation approach adjusts the uplink signal in advance to account for the large round-trip time, ensuring that timing synchronization accuracy is maintained despite the delayed feedback from the satellite.
2Measurement precision
If timing compensation is applied to maintain synchronization accuracy, then timing synchronization accuracy improves, but the system complexity increases due to additional phase rotation processing
Solution Approach 1:
The patent changes parameters by applying phase rotation to subcarriers in the frequency domain rather than modifying the time-domain signal directly. This parameter transformation allows timing error compensation to be achieved through complex multiplication of subcarrier components, which is computationally more efficient than time-domain interpolation or filtering methods, thus reducing the overall signal processing complexity while maintaining high timing synchronization accuracy.
3Reliability
If phase rotation is applied to compensate for timing errors, then timing synchronization accuracy improves, but the computational requirements increase
Solution Approach 1:
The patent substitutes mechanical time-domain signal processing with frequency-domain complex multiplication. By transforming the timing compensation operation from the time domain to the frequency domain via FFT, the computationally intensive convolution or interpolation operations are replaced with simple complex multiplication of subcarrier values, significantly reducing the computational power required while achieving the same timing synchronization accuracy.
Data Source
AI summary
A method for wireless communication by a user equipment (UE) includes modulating a symbol stream onto at least one subcarrier to generate an uplink signal in a frequency domain for transmitting to a receiver in a non-terrestrial network. The method also includes applying an amount of phase rotation to the at least one subcarrier in the frequency domain. The method further includes transforming the uplink signal from the frequency domain into a time domain uplink signal. The method includes transmitting the time domain uplink signal to the receiver, after applying the phase rotation to the at least one subcarrier.