Consolidated Neural Network Modulation Classification

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Solution Overview

Problem

The complexity of modern RF communication systems, driven by the proliferation of legacy and new RF standards and the adoption of Software Defined Radio technology, makes labor-intensive analysis unsustainable due to increased electromagnetic spectrum complexity, particularly in classifying baseband signals with varying modulation types and signal quality.

Innovation Solution

A consolidated neural network system that utilizes multiple data representations of baseband signal samples, including averaged Power Spectral Density, spectrogram, eye diagram, phase, and autocorrelation representations, processed by parallel neural networks to improve modulation classification performance, enabling accurate classification of RF signals with limited input data and handling noise and interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional expert feature analysis methods are used for modulation classification, then the system is easier to implement with simpler processing, but the classification performance deteriorates in complex electromagnetic spectrum environments with multiple RF standards and modulation types

Engineering Contradiction:
Improvemodulation classification performanceVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the modulation classification task by employing multiple parallel neural networks, each specialized in processing different data representations (time-domain, frequency-domain, time-frequency domain). This segmentation allows each network to focus on specific features while collectively achieving comprehensive classification performance, resolving the contradiction between accuracy and complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system merges multiple data representations and parallel neural network outputs into a unified classification decision. By combining results from different processing paths (time-domain analysis, frequency-domain analysis, time-frequency analysis), the system achieves superior classification performance that overcomes the limitations of single-method approaches.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple data representations are processed through parallel neural networks, then modulation classification accuracy improves across varying signal-to-noise ratios, but the computational complexity and processing requirements increase

Engineering Contradiction:
Improveclassification accuracy under varying signal conditionsVSAvoidprocessing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system dynamically adapts to varying signal-to-noise ratio conditions by processing multiple data representations simultaneously through parallel networks. Each network processes specific representations optimized for different SNR conditions, allowing the system to maintain high reliability across varying signal quality without requiring manual reconfiguration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes processing parameters by applying different transformations to the input signal (FFT for frequency domain, STFT for time-frequency, autocorrelation for time domain) before feeding them to specialized neural networks. This parameter diversification enables robust classification across varying SNR conditions while distributing computational load across multiple processing paths.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If hand-crafted expert features with a priori knowledge are used for signal classification, then the system requires less computational resources, but it becomes unsustainable in the face of proliferating RF communication standards and modulation types

Engineering Contradiction:
Improvecomputational resource consumptionVSAvoidadaptability to new RF standards and modulations
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The neural network system performs self-service by automatically learning optimal feature representations from raw signal data across multiple domains. Instead of relying on hand-crafted features requiring expert knowledge updates for each new standard, the system autonomously adapts to new RF standards and modulation types through its multi-domain processing architecture, reducing long-term computational overhead for maintaining classification capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The parallel neural network system achieves universality by processing multiple data representations that capture different aspects of the signal. This multi-functional approach allows the same system architecture to handle diverse RF standards and modulation types without requiring separate specialized processors, balancing computational efficiency with broad adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11586879B2Systems and methods for modulation classification of baseband signals using multiple data representations of signal samples
Publication Date: 2023.02.21 MOTOROLA SOLUTIONS INC
  • US11586879B2 patent drawing
  • US11586879B2 patent drawing
  • US11586879B2 patent drawing

AI summary

Systems and methods for classifying radio frequency signal modulations include receiving, at a consolidated neural network, a complex quadrature vector of interest representative of a baseband signal derived from a radio frequency signal, generating multiple data representations of the vector of interest, providing each data representation to one of multiple parallel neural networks in the consolidated neural network, and receiving, from the consolidated neural network, a classification result for the baseband signal. The consolidated neural network may be trained to classify baseband signals with respect to known modulation types by receiving complex quadrature training vectors, each including samples of a baseband signal derived from a radio frequency signal of known modulation type, comparing a classification result for the training vector to the known modulation type to determine modulation classification performance, and modifying a configuration parameter of the consolidated neural network dependent on the determined modulation classification performance.