Efficient Convolutional Networks for Robust Automatic Modulation Classification in OFDM-Based Wireless Systems

Thien Huynh‐The

doi:10.1109/JSYST.2022.3207377

2023-03-01

PRE

Thien Huynh‐The

Toan-Van Nguyen

Quoc‐Viet Pham

Daniel Benevides da Costa

Gi-Hyeob Kwon *

Dong‐Seong Kim

DOI：10.1109/JSYST.2022.3207377

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摘要

En 中文

Orthogonal frequency-division multiplexing (OFDM) is commonly deployed in Internet of Things (IoT) systems to achieve high data rates with reasonable complexity, where noncooperative protocols encode signals with different modulations for multiple users. However, conventional modulation recognition is limited to single-carrier communication systems, and there is an urgent need to design an effective method to blindly identify the unknown modulation format of received signals. In this article, we propose an automatic modulation classification method for the OFDM systems with the presence of channel deterioration. Our method first leverages a data reconstruction mechanism to arrange signals into high-dimensional data arrays and then exploits an efficient convolutional network, namely OFDMsym-Net, to learn underlying radio characteristics. OFDMsym-Net is designed by two kinds of processing modules, which manipulate one-dimensional asymmetric convolution filters to extract the intracorrelation within an OFDM symbol and the intercorrelation between different symbols. Moreover, a sophisticated structure with addition and concatenation layers is developed inside every module to improve learning efficiency. Based on simulation results achieved on a synthetic dataset of OFDM signals, our proposed method shows the classification robustness under various channel impairments. It reveals to have an overall accuracy of 95.41% at 10-dB signal-to-noise ratio, being superior to several state-of-the-art approaches.

Keyword:

OFDM

Modulation

Symbols

Convolution

Feature extraction

Internet of Things

Signal to noise ratio

Automatic modulation classification (AMC)

convolutional neural networks (CNNs)

frequency-selective multipath Rayleigh fading

orthogonal frequency-division multiplexing (OFDM)