Noise Power Estimation Using Maximum-Likelihood Signal Separation
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Solution Overview
Problem
Conventional power-measuring devices cannot separately determine payload-signal power and noise power from a received signal with superposed noise, making it impossible to calculate the signal-noise ratio.
Innovation Solution
A method using maximum-likelihood estimation to estimate the mean power of an undisturbed periodic signal sequence from the received signal, with a weighting factor to compensate for estimation errors, allowing for the separation of noise and payload-signal powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional power-measuring devices measure the total power of a received signal with superposed noise, then the total power measurement is obtained, but the payload-signal power and noise power cannot be determined separately
Solution Approach 1:
The patent segments the total received signal power into two distinct components: payload-signal power and noise power. By using maximum-likelihood estimation, the device separates the superposed signal and noise components mathematically, allowing independent determination of each component's power without requiring physical separation of the signal components.
Solution Approach 2:
The patent introduces an intermediary estimation process that uses the known periodic structure of the transmitted signal as a mediator. By comparing the received signal against the known signal structure through maximum-likelihood estimation, the system can extract signal power information while isolating noise power, acting as a mathematical intermediary between the mixed received signal and the separate power measurements.
2Measurement precision
If maximum-likelihood estimation is used to estimate the undisturbed periodic transmitted-signal sequence, then the estimated-signal sequence is obtained, but estimation error occurs between the estimated sequence and the actual sequence
Solution Approach 1:
The patent employs feedback by using the estimated-signal sequence to calculate noise power, which then feeds back into the overall power measurement system. The estimation error is compensated for by using the difference between total received power and estimated signal power, creating a feedback mechanism that accounts for and corrects estimation inaccuracies in the final noise power determination.
3Measurement precision
If multiple periods of the transmitted-signal sequence are used in estimation, then the estimation accuracy is improved, but the computational complexity increases
Solution Approach 1:
The patent leverages the periodic nature of the transmitted signal by using multiple periods in the maximum-likelihood estimation process. By exploiting the repeating structure of the signal across periods, the system improves estimation accuracy through averaging and pattern recognition, while the periodic structure itself provides a natural framework that simplifies the computational approach compared to analyzing non-periodic signals.
Data Source
AI summary
A device for determining an estimated value for a mean power of the noise-signal sequence, which is superposed on an undisturbed periodic transmitted-signal sequence, determines a mean power of a received-signal sequence, which corresponds to the undisturbed periodic transmitted-signal sequence with the addition of the superposed noise-signal sequence. It then estimates an estimated-signal sequence for the undisturbed periodic transmitted-signal sequence from the received-signal sequence. Following this, a mean power of the estimated-signal sequence and the estimated value of the mean power of the noise-signal sequence is determined from a difference between the determined mean power of the received-signal sequence and the determined mean power of the estimated-signal sequence.