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Wyświetlanie 1-15 z 26
Tytuł:
Subcarrier Gain Based Power Allocation in Multicarrier Systems
Autorzy:
Abd-Elnaby, M.
Sedhom, G. G.
Messiha, N. W.
Abd El-Samie, F. E.
Zhu, X.
Powiązania:
https://bibliotekanauki.pl/articles/958110.pdf
Data publikacji:
2014
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
GPA
OFDM
QAM
SNR
Opis:
The Orthogonal Frequency Division Multiplexing (OFDM) transmission is the optimum version of the multicarrier transmission scheme, which has the capability to achieve high data rate. The key issue of OFDMsystem is the allocation of bits and power over a number of subcarriers. In this paper, a new power allocation algorithm based on subcarrier gain is proposed to maximize the bit rate. For OFDM systems, the Subcarrier Gain Based Power Allocation (SGPA) algorithm is addressed and compared with the standard Greedy Power Allocation (GPA). The authors demonstrate by analysis and simulation that the proposed algorithm reduces the computational complexity and achieves a near optimal performance in maximizing the bit rate over a number of subcarrier.
Źródło:
Journal of Telecommunications and Information Technology; 2014, 1; 62-67
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved Downlink MC-CDMA System for Effcient Image Transmission
Autorzy:
Bendelhoum, M. S.
Djebbari, A.
Boukli-Hacene, I.
Taleb-Ahmed, A.
Powiązania:
https://bibliotekanauki.pl/articles/308187.pdf
Data publikacji:
2017
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
data compression
MC-CDMA
MSSIM
performance evaluation
PSNR
SNR
SPIHT
Opis:
Image compression is an essential stage of the data archiving and transmitting process, as it reduces the number of bits and the time required to complete the transmission. In this article, a study of image transmission over the Multi-Carrier Code Division Multiple Access (MC-CDMA) downlink system is presented. The solution proposed relies on source coding combined with channel coding. The Discrete Wavelet Transform (DWT) method is used in conjunction with the SPIHT coder to compress the image, then the data generated is transmitted with the MC-CDMA technique over a noisy channel. The results show that image transmissions performed over MC-CDMA using the SPIHT model are better than the traditional approach like MC-CDMA in the AWGN channel.
Źródło:
Journal of Telecommunications and Information Technology; 2017, 4; 5-16
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel
Autorzy:
Bendelhoum, Mohammed Sofiane
Lahcene, Mohamed Rida
Menezla, Fayssal
Elarbi, Abderraouf
Powiązania:
https://bibliotekanauki.pl/articles/1839490.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
BER
MIMO
SNR
STBC
STTC
TCM
TCM-STBC
Opis:
Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different values of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 1-7
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel
Autorzy:
Bendelhoum, Mohammed Sofiane
Lahcene, Mohamed Rida
Menezla, Fayssal
Elarbi, Abderraouf
Powiązania:
https://bibliotekanauki.pl/articles/1839476.pdf
Data publikacji:
2021
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
BER
MIMO
SNR
STBC
STTC
TCM
TCM-STBC
Opis:
Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different values of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5.
Źródło:
Journal of Telecommunications and Information Technology; 2021, 1; 1-7
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Inclusive Performance Analysis of Single-branch Single-relay AF Transmission in a Mixed Rayleigh-Nakagami-m Fading Environment
Autorzy:
Benmahmoud, Slimane
Powiązania:
https://bibliotekanauki.pl/articles/307994.pdf
Data publikacji:
2019
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
amplify-and-forward (AF)
decode-and-forward (DF)
two/dual-hop relaying
outage probability
ergodic capacity
signal-to-noise ratio (SNR)
Opis:
In this paper, the end-to-end performance of a single-branch two-hop amplify-and-forward (AF) relaying network in a mixed Rayleigh-Nakagami-m fading environment, is investigated. Four different fading scenarios and three standard relay configurations for each scenario are considered. Exact analytical expressions for the outage probability and tight upper bounds for the ergodic capacity are derived. Results of Monte Carlo simulations are provided to verify the accuracy of the analytical results.
Źródło:
Journal of Telecommunications and Information Technology; 2019, 3; 39-48
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Viability and genetic diversity of Populus nigra population from riparian forest in SNR Gornje Podunavlje
Autorzy:
Čortan, Dijana
Tubić, Bojan
Powiązania:
https://bibliotekanauki.pl/articles/956812.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
black poplar
viability assessment
genetic diversity
ssr markers
snr upper danube
Opis:
Populus nigra L. is one of the rarest and most endangered tree species in Western and Central Europe. Its genetic diversity is of great importance in enabling a native riparian population to survive and reproduce under changing environmental conditions. The aim of this research was assessment of P. nigra viability in one of the best preserved riparian ecosystems in Europe, Special Nature Reserve “Gornje Podunavlje” (Upper Danube), Serbia. Additionally, the analysis of the genetic diversity was made to support the effective conservation in the future. During our study, we have mapped 931 P. nigra trees, which were used for the assessment of present native population. Furthermore, we used 14 microsatellite markers to assess the genetic structure of this this population. Viability assessment showed considerable occurrence of P. nigra in the research area, even though the results show fragmentation. P. nigra occurs mostly individually or in small groups of trees, and has a non-sustainable age structure due to insufficient or lacking regeneration. Despite the limited size of the studied population, the apparent overall genetic diversity was high (He = 0.759) and comparable to other known native populations of P. nigra along the Danube basin. However, the results also confirmed existence of recent bottleneck effect. Significantly positive and quite high Fis value (0.147) was noted, which may be ascribed to the “Wahlund effect” because of the population substructure that was revealed by the STRUCTURE analysis (K=2). Although results say that coverage of native stands is not so promising, most of selected trees within our research assessed showed good viability with potential for natural reproduction However, the problem is that suitable areas for natural seedling establishment are scarce and with that gene flow is probably limited. The fragmentation of the area must be reduced and isolated stands must be interlinked as there is need to create larger non-fragmented areas.
Źródło:
Dendrobiology; 2017, 78; 157-167
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effectiveness of the spatial acceleration modulus for rolling elements bearing fault detection
Autorzy:
Cotogno, M.
Cocconcelli, M.
Rubini, R.
Powiązania:
https://bibliotekanauki.pl/articles/329466.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
rolling element bearing
diagnostic
spatial acceleration modulus
SAM
SNR
spectral Kurtosis
envelope analysis
Opis:
Rolling Elements Bearing (REB) condition monitoring is mainly based on the analysis of acceleration (vibration) signal in the load direction. This is one of the three components of the acceleration vector in 3D space: the main idea of this paper is the recovery of additional fault information from the other two acceleration vector components by combining them to obtain the modulus of the spatial acceleration (SAM) vector. The REB diagnostic performances of the SAM are investigated and compared to the load direction of vibration by means a rough estimator of the “Signal-to-Noise” Ratio and the Spectral Kurtosis. The SAM provides a higher SNR than the single load direction. Finally, Spectral Kurtosis driven Envelope analysis is performed for further comparison of the two signals: its results highlight that demodulation of the SAM isn’t stricly necessary to extract the fault features, which are already available in the raw signal spectrum.
Źródło:
Diagnostyka; 2013, 14, 4; 27-34
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of advanced optical modulation format and estimation of signal-to-noise-ratio based on parallel-twin convolutional neural network
Autorzy:
Dong, Xiaowei
Yu, Zhihui
Powiązania:
https://bibliotekanauki.pl/articles/27310103.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
deep learning
PT-CNN
parallel-twin convolutional neural network
constellation diagram
modulation format identification
SNR estimation
Opis:
In this paper, we design a parallel-twin convolutional neural network (PT-CNN) deep learning model and use the signal constellation diagram to realize the identification of six advanced optical modulation formats (QPSK, 4QAM, 8PSK, 8QAM, 16PSK, 16QAM) and signal-to-noise-ratio (SNR) estimation. The influence of PT-CNN with different layers and kernel sizes is investigated and the optimal network model is chosen. Simulation results demonstrate that the proposed method has the advantages of not requiring manual feature extraction, having the ability to clearly distinguish the six modulation formats with 100% accuracy when SNR of the received signal sequences is higher than 12 dB. In addition, the high-accurate SNR estimation is realized simultaneously without increasing additional system complexity.
Źródło:
Optica Applicata; 2023, 53, 2; 281--289
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ANSDM converters dynamic range design process
Autorzy:
Golański, Ryszard
Godek, Juliusz
Powiązania:
https://bibliotekanauki.pl/articles/1402376.pdf
Data publikacji:
2020
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
delta modulation
non-uniform sampling
SNR
dynamic range
Lambert W function
sampling interval
Maple
modulacja delta
nierównomierne próbkowanie
zakres dynamiczny
funkcja Lamberta
odstęp próbkowania
Opis:
The results of analytic and simulating works proved that for nonstationary sources, the delta converters with adaptive sampling expose higher coding efficiency than the former proposals, based on uniform sampling methods. The knowledge of the sampling interval range and the algorithm of the Nonuniform Sampling Delta Modulation and Adaptive Nonuniform Sampling Delta Modulation allows finding the necessary number of the sampling intervals and their values that maximizes SNR. The total dynamic range of the ANSDM modulator is the product of the dynamic range both from sampling interval and step size adaptation. Due to the high complexity of the calculations, the ANSDMsoft program was developed to support computing. All computational works were carried out using the Maple environment. Maple allows to solve complex mathematical functions and display their results in a simple way. Most importantly, it supports the LambertW function, used in the computing of NSDM or ANSDM modulators parameters. Graphic illustrations of the NSDM and ANSDM modulator dynamic range as a function of the minimum and maximum sampling frequency are presented.
Źródło:
Science, Technology and Innovation; 2020, 10, 3; 1-7
2544-9125
Pojawia się w:
Science, Technology and Innovation
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Wykorzystanie zmodernizowanej aparatury oblotu technicznego zainstalowanej na samolocie SONEX LL do oblotu stacji naprowadzania rakiet systemu NEWA
Use of modernized flight test equipment onboard of SONEX LL aircraft to fly the Newa Missile Guidance System
Autorzy:
Karczmarz, Dariusz
Mądrzycki, Przemysław
Szkudlarz, Henryk
Grzywiński, Stanisław
Podciechowski, Maciej
Żygadło, Stanisław
Powiązania:
https://bibliotekanauki.pl/articles/38943397.pdf
Data publikacji:
2023
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
aparatura
oblot techniczny
stacja naprowadzania rakiet
kontrola parametrów technicznych
SNR
technical flight
equipment
missile guidance station
control of technical parameters
Opis:
W artykule omówiono modernizację aparatury do przeprowadzania oblotów technicznych Przeciwlotniczego Zestawu Rakietowego NEWA SC (SA-3 Goa – kod NATO) polegającą na zastąpieniu samolotu TS-11 Iskra samolotem SONEX LL oraz przystoso-waniu zestawu aparatury oblotowej montowanej dotychczas na TS-11 Iskra do nowego samolotu-nosiciela. Przeprowadzono badania porównawcze w warunkach poligonowych, które potwierdziły poprawność przyjętych rozwiązań technicznych.
The article discusses the modernization of the Anti-Aircraft Missile System NEWA SC (SA-3 Goa – NATO code) flight test equipment, consisting in replacing the TS-11 Iskra aircraft with the SONEX LL aircraft and adapting the set of flight test equipment previously mounted on the TS-11 Iskra to the new carrier aircraft. Comparative tests were carried out in field conditions, which confirmed the correctness of the adopted technical solutions.
Źródło:
Journal of KONBiN; 2023, 53, 4; 61-78
1895-8281
2083-4608
Pojawia się w:
Journal of KONBiN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hardware Implementation of MISO on Orthogonal Frequency Division Multiplexing Platform with the Help of Alamouti Algorithm
Autorzy:
Kilaru, S.
Powiązania:
https://bibliotekanauki.pl/articles/226220.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
MISO
SISO
FPGA
Xilinx
BER
SNR
Alamouti
LTE
Opis:
Many software based OFDM techniques were proposed from last half decade to improve the performance of the system. This paper tried to implement the same with Hardwar implementation. We created Hardware based MISO platform with OFDM. We implemented Alamouti algorithm on this test bed. The test bed is implemented with the help of Field Programmable Gate Array (FPGA). The test bed is functionalized with the help of FPGA through Xilinx based system generator for DSP. In this paper we considered the 2×1 MISO implementation with Alamouti algorithm. The simulation results showed that BER and SNR are considerably high for MISO than SISO. The results also proved that proposed OFDM based Alamouti implementation for MISO is excellent in all performance criterions.
Źródło:
International Journal of Electronics and Telecommunications; 2017, 63, 2; 137-143
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estymacja współczynnika SNR w sygnale harmonicznym przy pomocy wygładzania wykładniczego
The estimation of SNR in the harmonic signal using the exponential smoothing
Autorzy:
Kowalski, J.
Pęksiński, J.
Mikołajczak, G.
Powiązania:
https://bibliotekanauki.pl/articles/252968.pdf
Data publikacji:
2015
Wydawca:
Instytut Naukowo-Wydawniczy TTS
Tematy:
współczynnik SNR
wygładzanie
filtracja
szum
estymacja
SNR factor
smoothing
filtering
noise
estimation
Opis:
W pracy przedstawiono metodę estymacji współczynnika SNR opartą o wygładzanie wykładnicze i założenie, że w procesie filtracji tłumiony jest tylko szum. Znajomość współczynnika redukcji szumu pozwala wyznaczyć wartość estymowanej wielkości.
The paper presents the SNR estimation method based on exponential smoothing, and the assumption that the filtration process only noise is suppressed. Knowledge of Noise Reduction Coefficient lets you determine the value of the estimated size.
Źródło:
TTS Technika Transportu Szynowego; 2015, 12; 834-836, CD
1232-3829
2543-5728
Pojawia się w:
TTS Technika Transportu Szynowego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sampling Jitter in Audio A/D Converters
Autorzy:
Kulka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/177046.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog-to-digital converter
ADC
successive approximation register (SAR)
sigma-delta ADC
sample-and-hold circuit
DT sigma delta modulator
CT sigma delta modulator
time jitter
aperture jitter
clock jitter
periodic clock jitter
signal-to-noise ratio (SNR)
Opis:
This paper provides an overview of the effects of timing jitter in audio sampling analog-to-digital converters (ADCs), i.e. PCM (conventional or Nyquist sampling) ADCs and sigma-delta (ΣΔ) ADCs. Jitter in a digital audio is often defined as short- term fluctuations of the sampling instants of a digital signal from their ideal positions in time. The influence of the jitter increases particularly with the improvements in both resolution and sampling rate of today’s audio ADCs. At higher frequencies of the input signals the sampling jitter becomes a dominant factor in limiting the ADCs performance in terms of signal-to-noise ratio (SNR) and dynamic range (DR).
Źródło:
Archives of Acoustics; 2011, 36, 4; 831-849
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of Hybrid Sensing Method in Environment with Noise Uncertainty
Autorzy:
Kustra, M.
Kosmowski, K.
Suchański, M.
Powiązania:
https://bibliotekanauki.pl/articles/308868.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
Covariance Absolute Value
Cyclic Autocorrelation Function
hybrid detector
noise uncertainty
OFDM
SNR wall
WiMAX
Opis:
The paper presents a novel hybrid spectrum sensing method used in cognitive radio and presents a hybrid detector (HD) which improves the sensing performance. The proposed HD takes advantage of the energy detection (ED) principle and a method based on Covariance Absolute Value (CAV), as well as on Cyclic Autocorrelation Function (CAF). The paper shows the limitations of using ED, resulting from the uncertainty of spectral density of noise power estimation, known as the SNR wall. The paper describes a system model and presents simulation results for the OFDM signal of a WiMAX-based communications system. The simulation results refer to an ideal environment with well-known parameters, and to an environment with uncertain spectral density of noise power estimation.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 1; 51-57
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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