Channel Echo Estimation Without Demodulation
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Solution Overview
Problem
Existing digital communication systems face challenges in estimating communication channel echoes, especially in poor channel conditions with high noise levels or significant multipath interference, which prevents channel evaluation and demodulation.
Innovation Solution
A method that estimates channel echoes and modulation parameters without demodulating the signal or using pilot signals, employing calculations based on the radio channel's time-domain representation and trigonometric relationships to distinguish between main and secondary beams, allowing for channel response analysis without adaptive filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot signals are inserted into the modulation to evaluate the channel, then channel estimation is possible under normal conditions, but the method fails in poor channel conditions with high noise or multipath interference
Solution Approach 1:
The invention extracts channel echo information directly from the received signal without requiring pilot signals. By analyzing the received signal structure and applying IFFT operations, the method extracts impulse response characteristics that reveal channel echo parameters, eliminating the need for separate pilot signal insertion and demodulation steps.
Solution Approach 2:
Instead of the conventional approach of inserting pilots and demodulating to estimate channels, the invention inverts the process by directly analyzing the received signal's spectral characteristics and applying inverse Fourier transform to obtain channel impulse response, thereby estimating echoes without traditional demodulation.
2Reliability
If adaptive filtering algorithms are used to evaluate channel echoes, then echo cancellation is achieved, but the method still requires signal demodulation and pilot signals
Solution Approach 1:
The invention extracts channel echo information directly from the received signal structure without requiring adaptive filtering or signal demodulation. By analyzing the spectral characteristics and applying IFFT, the method extracts impulse response characteristics that directly reveal channel echo parameters, simplifying the processing chain.
3Loss of information
If signal demodulation is performed to estimate channel parameters, then modulation parameters can be determined, but the process fails when channel conditions prevent successful demodulation
Solution Approach 1:
The invention performs preliminary analysis of the received signal's spectral characteristics before attempting full demodulation. By examining the signal structure and applying IFFT operations on selected spectral portions, the method obtains channel impulse response and modulation parameters in advance, enabling system configuration before actual data transmission begins.
Data Source
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AI summary
The method involves utilizing orthogonal frequency division basis multiplexing, where no signal demodulation takes place, digitizing of signal of interest and processing the digital system. Fourier transformation technique is utilized instead of inverse Fourier transformation, where signal is utilized according to Digital video broadcasting-terrestrialor Digital video broadcasting-second generation terrestrial. An independent claim is also included for system for the execution of echoes estimating method.