Dynamic Window Length Adjustment for Correlation Matrix Estimation

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Solution Overview

Problem

Existing correlation matrix estimation methods, such as those used in adaptive beamforming and blind source separation, face challenges in achieving accurate and rapid convergence due to the dependence on window length, leading to errors that are inversely proportional to the window size, especially when estimating uncorrelated signals.

Innovation Solution

A signal processing device that includes a state detection unit, correlation calculation unit, correlation estimation unit, estimated error evaluation unit, and window length adjusting unit, which uses an exponential window with dynamically adjusted length based on an allowable error rate and maximum window length to reduce estimated errors, thereby improving convergence rate and estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed window length is used for correlation matrix estimation, then the calculation is simple, but the estimation accuracy is insufficient due to errors inversely proportional to window size

Engineering Contradiction:
Improvecorrelation matrix estimation accuracyVSAvoidwindow length adjustment mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transitioning from a fixed window length to a dynamically adjustable window length that adapts to signal characteristics. The window length adjustment unit modifies the window length based on signal variance and correlation values, enabling the system to optimize estimation accuracy for different signal conditions rather than using a static parameter.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the window length parameter based on signal properties. The system calculates signal variance and correlation values, then adjusts the window length parameter accordingly - increasing it when estimation accuracy is insufficient and decreasing it when signals change rapidly, thereby optimizing the correlation matrix estimation under varying conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a long window length is used, then the estimation accuracy improves, but the convergence rate decreases and tracking of signal variations becomes slow

Engineering Contradiction:
Improvecorrelation value estimation accuracyVSAvoidconvergence rate and tracking speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The system dynamically adjusts the window length based on real-time signal characteristics. When the signal variance is low and correlation values are stable, a longer window length is used to improve estimation accuracy. When signal variations are detected, the window length is reduced to maintain fast convergence and tracking capability, thus resolving the trade-off between accuracy and speed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the estimated correlation values and signal variance are continuously monitored. Based on this feedback, the window length adjustment unit modifies the window length to optimize performance - extending it when accuracy is needed and shortening it when rapid adaptation is required, creating a closed-loop control system.

Inventive Principle:
Principle #23Feedback

3Speed

If a short window length is used, then the convergence rate is fast, but the estimation accuracy deteriorates due to increased error

Engineering Contradiction:
Improveconvergence rateVSAvoidcorrelation matrix estimation accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The system uses dynamic window length adjustment to overcome the limitations of fixed short windows. By extending the window length when signal conditions permit (low variance, stable correlation), the system achieves high estimation accuracy while maintaining fast convergence through the ability to quickly adjust the window parameter in response to signal changes.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If the window length is increased to reduce estimation error, then the accuracy improves, but the amount of calculation and storage increases

Engineering Contradiction:
Improvecorrelation matrix estimation accuracyVSAvoidcomputational resources and storage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent dynamically adjusts the window length to use computational resources efficiently. Instead of always using a long window that demands high resources, the system extends the window length only when necessary (when signal variance is low and accurate estimation is prioritized), and reduces it when rapid adaptation is needed or resources are constrained, optimizing the balance between accuracy and computational load.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS8799342B2Signal processing device
Publication Date: 2014.08.05 HONDA MOTOR CO LTD
  • US8799342B2 patent drawing
  • US8799342B2 patent drawing
  • US8799342B2 patent drawing

AI summary

A device capable of improving the convergence rate and estimation accuracy in estimating a correlation value. According to a signal processing device, since a window length is adjusted in such a manner to reduce an estimated error of a correlation matrix, the convergence rate and estimation accuracy in estimating the correlation matrix and the correlation value as its off-diagonal element can be improved. Then, in such a high-probability condition that the correlation of plural output signals according to a state is estimated with a high degree of precision, signal processing is performed on the plural signals, so that the state can be estimated with a high degree of precision.