Receiver Frequency Response Estimation via Spectral Comparison
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Solution Overview
Problem
In broadband satellite communications, inconsistent frequency response due to varied or inconsistent frequency response at the transmitter and channel leads to significant tilt, ripple, and group delay issues, affecting the quality of received signals, necessitating a method to estimate and compensate for these effects.
Innovation Solution
The method involves performing a first spectral estimation on an initial version of a wireless signal and a second spectral estimation on the received signal, comparing the two to estimate the frequency response, and pre-distorting subsequent signals to compensate for the estimated frequency response, using a subscriber terminal and gateway device in a satellite communications system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spectral estimation is performed on both initial and received signals to estimate frequency response, then signal quality is improved, but device complexity increases
Solution Approach 1:
The system performs spectral estimation on the initial transmitted signal before transmission to establish a reference frequency response. This preliminary action allows the receiver to compare the received signal's spectral characteristics against the known initial signal, enabling frequency response estimation without requiring complex adaptive algorithms at the receiver.
2Reliability
If frequency response estimation is performed to compensate for tilt and ripple, then communication reliability is improved, but processing time increases
Solution Approach 1:
The patent replaces complex iterative frequency response estimation algorithms with a direct spectral comparison method. By comparing the spectral estimates of the initial and received signals, the system directly calculates the frequency response without requiring multiple iterations or complex optimization, significantly reducing processing time while maintaining accuracy in compensating for tilt and ripple effects.
3Stability of the object's composition
If pre-distortion is applied to compensate for frequency response, then signal consistency is improved, but transmitter complexity increases
Solution Approach 1:
The system uses spectral estimation results as an intermediary to determine pre-distortion parameters. Instead of directly implementing complex pre-distortion filtering, the transmitter applies simple amplitude and phase adjustments based on the spectral comparison data, achieving signal consistency through this intermediate spectral analysis step rather than through complex direct filtering.
Data Source
AI summary
Methods, systems, and devices are described for estimating a frequency response using a received signal. A first spectral estimation is performed on a digitized representation of an initial version of a wireless signal. A second spectral estimation is performed on the digitized representation of the wireless signal as received from the transmitter. The first spectral estimation is compared with the second spectral estimation to estimate a frequency response. A later signal transmitted from the transmitter may be pre-distorted to compensate for the estimated frequency response. The disclosed frequency response estimation techniques may be used in a satellite communications system.