Temat: SNR - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: A model of OFDM based maritime VHF communication system for data exchange
Autorzy:: Valčić, S.
Pogány, T.
Mrak, Z.
Powiązania:: https://bibliotekanauki.pl/articles/260386.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: maritime VHF communications
OFDM modulation
AWGN
SNR
BER
Opis:: In the maritime Very High Frequency (VHF) band, there are no systems for transmitting large amounts of data. Therefore, it is necessary to develop new systems that would modernize the Global Maritime Distress and Safety System (GMDSS), significantly relieve the Automatic Identification System’s (AIS) communication channels, and set guidelines for the development of communication infrastructure of the e-Navigation. In line with this, analytical and simulation models of the maritime VHF data transmission communication system using Orthogonal Frequency Division Multiplexing (OFDM) modulation are worked out in this paper. The achieved data rate, the spectral efficiency and the bit error rate (BER) represent validation parameters on which the results of the analytical and simulation models are evaluated. It is concluded that the application of the digital OFDM modulation in the maritime VHF band may improve the GMDSS system by achieving higher data rates compared to the current terrestrial mandatory systems for data exchange, i.e. Digital Selective Calling (DSC) and AIS.
Źródło:: Polish Maritime Research; 2018, 2; 27-36
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
Autorzy:: Ju, Yang
Wei, Zhengxian
Li, Huangfu
Feng, Xiao
Powiązania:: https://bibliotekanauki.pl/articles/259300.pdf
Data publikacji:: 2020
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: acoustic
low SNR
signal classification
feature maintain
dimension reduction
Opis:: The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
Źródło:: Polish Maritime Research; 2020, 2; 187-198
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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