Date of Award

3-2005

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Electrical and Computer Engineering

First Advisor

Michael A. Temple, PhD

Abstract

Modulation recognition is important for both military and commercial communication applications, particularly in cases where enhanced situation awareness and/or channel assessment is required to mitigate intentional or collateral interference. Modulation recognition via template matching or statistical analysis is a key aspect of non-cooperative (nonmatched filtering) signal interception, classification, and exploitation. This research concerns the evaluation and modification of a conventional Digitally Modulated Signal Recognition Algorithm (DMRA) to enable multi-carrier, Orthogonal Frequency Division Multiplexing (OFDM), waveform recognition. The original DMRA architecture was developed to classify communication signals for three fundamental data modulations, i.e., Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), and Frequency Shift Keying (FSK). By adding an additional key feature and threshold to the original DMRA architecture, a modified DMRA architecture is developed to enable the reliable recognition of OFDM waveforms. Simulation results for the modified DMRA architecture show a 95.25% success rate for OFDM waveform recognition at a signal-to-noise ratio (SNR) of 11:0 dB. When operated under scenarios where FSK signals are neither present nor considered an alternative, the modified DMRA architecture yields success rates of 100%, 98.25%, and 98.25% for classifying PSK2, PSK4, and OFDM at a SNR of 5.0 dB.

AFIT Designator

AFIT-GE-ENG-05-23

DTIC Accession Number

ADA435255

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