Rank Estimation in Mobile Signal Processing via Eigenvalue Discriminant

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Solution Overview

Problem

The calculation of matrix rank in signal processing for mobile telecommunication systems is computationally complex, particularly in mobile stations with limited resources, due to the need for iterative methods and complex square root operations in solving characteristic equations.

Innovation Solution

A method that approximates the eigenvalue ratio of a channel matrix representation by avoiding the square root operation, using a test function based on the sum and difference of squared elements to determine the number of independent spatially parallel communication streams, thereby reducing computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If iterative methods are used to calculate the rank of the channel matrix, then the rank estimation accuracy is improved, but the computational complexity increases significantly

Engineering Contradiction:
Improverank estimation accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a simplified test function based approach that requires only basic arithmetic operations (addition, multiplication, comparison) instead of complex iterative algorithms. This disposable calculation method provides sufficient accuracy for rank estimation without requiring computationally expensive iterative procedures, making it suitable for mobile stations with limited processing resources.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If the characteristic equation method is used to calculate the rank, then the theoretical accuracy is improved, but the implementation complexity increases due to square root operations

Engineering Contradiction:
Improverank calculation accuracyVSAvoidimplementation complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the problematic square root operation from the characteristic equation method. By formulating a test function that uses only the coefficients of the characteristic equation (which can be computed from channel matrix elements) and compares them using basic arithmetic, the solution removes the computationally intensive square root calculation while preserving the essential rank determination capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If complex square root operations are performed to solve the characteristic equation, then the rank determination accuracy is improved, but the processing time increases

Engineering Contradiction:
Improverank determination accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs a computationally inexpensive test function that requires only basic arithmetic operations (addition, multiplication, and comparison) to determine the rank. This disposable calculation method avoids time-consuming square root operations and iterative procedures, providing sufficient accuracy for real-time mobile communication applications with minimal processing time.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS8014727B2Signal processing in electronic apparatus
Publication Date: 2011.09.06 NOKIA TECHNOLOGIES OY
  • US8014727B2 patent drawing
  • US8014727B2 patent drawing
  • US8014727B2 patent drawing

AI summary

A method, apparatus, and computer program for estimating a rank, i.e. the number of uncorrelated spatial channels, of a radio channel are provided. The rank estimation is carried out by examining mutual proportions of a first eigenvalue and a second eigenvalue of a two-by-two channel matrix representation with a test function including elements of a solution of roots of a quadratic characteristic equation of the two-by-two channel matrix representation, wherein the test function comprises a discriminant of the solution of the roots of the quadratic characteristic equation without a square root operation.