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    Wyświetlanie 1-14 z 14
    Tytuł:
    Shallow Water Experiment of OFDM Underwater Acoustic Communications
    Autorzy:
    Kochańska, Iwona
    Schmidt, Jan H.
    Marszal, Jacek
    Powiązania:
    https://bibliotekanauki.pl/articles/177592.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    underwater acoustic communications
    UAC
    orthogonal frequency-division multiplexing
    OFDM
    Opis:
    The large variability of communication properties of underwater acoustic channels, and especially the strongly varying instantaneous conditions in shallow waters, is a challenge for the designers of underwater acoustic communication (UAC) systems. The use of phase modulated signals does not allow reliable data transmission through such a tough communication channel. However, orthogonal frequency-division multiplexing (OFDM), being a multi-carrier amplitude and phase modulation technique applied successfully in the latest standards of wireless communications, gives the chance of reliable communication with an acceptable error rate. This paper describes communication tests conducted with the use of a laboratory model of an OFDM data transmission system in a shallow water environment in Wdzydze Lake.
    Źródło:
    Archives of Acoustics; 2020, 45, 1; 11-18
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spectrum Allocation Policy in Elastic Optical Networks
    Autorzy:
    Olszewski, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/227011.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    routing and spectrum allocation problem (RSA)
    spectrum fragmentation
    orthogonal frequency-division multiplexing (OFDM)
    Opis:
    The considered problem covers routing and spectrum allocation problem (RSA problem) in Elastic Optical Networks while maintaining the spectrum continuity constraints, non-overlapping spectra constraints for adjacent connections on individual links of the network and spectrum contiguity constraints of the connection. In this article the modified version of the First Fit spectrum slot allocation policy for Fixed Alternate Routing in flexible optical networks has been proposed. The Fixed Alternate Routing with proposed spectrum allocation policy rejects fewer requests, provides less bandwidth blocking probability and less spectrum fragmentation than Fixed Alternate Routing with well-known First Fit and Exact Fit spectrum allocation policies. However, the cost of improving these parameters is a higher computational complexity of the proposed allocation policy.
    Źródło:
    International Journal of Electronics and Telecommunications; 2017, 63, 4; 423-429
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    OFDM Performance of Ultra Wideband in Wireless Body Area Network Channel
    Autorzy:
    Karan, Y.
    Şaylı, O.
    Kahveci, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1031485.pdf
    Data publikacji:
    2017-09
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    wireless body area network channel
    orthogonal frequency-division multiplexing
    least square channel estimation
    interpolation
    Opis:
    Data transfer for health monitoring can be highly critical because of life dependency transmitted data. IEEE 802.15.6 is a standard for wireless body area network published in 2012 to satisfy the reliability which is required by health monitoring systems. Ultra wideband is one of proposed physical layer technologies specified in the wireless body area network standard which offers high bandwidth, low power, and low interference with other devices. Orthogonal frequency-division multiplexing is commonly used to transmit the data in many wireless communication standards due to its high spectral efficiency and immunity to the inter symbol interference. In this study, bit-error rate performance for orthogonal frequency-division multiplexing with different interpolation based least square channel estimation is given for wireless body area network channel model. OFDM symbol length and pilot length used in OFDM symbol is investigated in bit error rate - signal to noise ratio graphs.
    Źródło:
    Acta Physica Polonica A; 2017, 132, 3; 574-576
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Damped Zero-Pseudorandom Noise OFDM Systems
    Autorzy:
    Esmaiel, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/225983.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    time reversal
    TR
    channel estimation
    CE
    compressed sensing
    CS
    orthogonal frequency division multiplexing
    OFDM
    Opis:
    This paper proposed a new OFDM scheme called damped zero-pseudorandom noise orthogonal frequency division multiplexing (DZPN-OFDM) scheme. In the proposed scheme, ZPN-OFDM non-zero part is damped to reduce its energy, thus the mutual interference power in-between the data and training blocks with conservative the pseudo-noise conventional properties required for channel estimation or synchronization. The motivation of this paper is the OFDM long guard interval working in wide dispersion channels, whereas a significant energy is wasted when the conventional ZPN-OFDM is used as well as the BER performance is also degraded. Moreover, the proposed scheme doesn’t duplicate the guard interval to solve the ZPN-OFDM spectrum efficiency loss problem. Both detailed performance analysis and simulation results show that the proposed DZPNOFDM scheme can, indeed, offer significant bit error rate, spectrum efficiency and energy efficiency improvement.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 4; 433-438
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Impulse Noise Suppression Based on Power Iterative ICA in Power Line Communication
    Autorzy:
    Zhang, Wei
    Luo, Zhongqiang
    Xiong, Xingzhong
    Powiązania:
    https://bibliotekanauki.pl/articles/226439.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    power line communication(PLC)
    orthogonal frequency division multiplexing(OFDM) signal
    independent component analysis(ICA)
    impulse noise
    Opis:
    To overcome the detrimental influence of impulse noise in power line communication and the trap of scarce prior information in traditional noise suppression schemes , a power iteration based fast independent component analysis (PowerICA) based noise suppression scheme is designed in this paper. Firstly, the pseudo-observation signal is constructed by weighted processing so that single-channel blind separation model is transformed into the multi-channel observed model. Then the proposed blind separation algorithm is used to separate noise and source signals. Finally, the effectiveness of the proposed algorithm is verified by experiment simulation. Experiment results show that the proposed algorithm has better separation effect, more stable separation and less implementation time than that of FastICA algorithm, which also improves the real-time performance of communication signal processing.
    Źródło:
    International Journal of Electronics and Telecommunications; 2019, 65, 4; 651-656
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modulation-Mode Assignment in SVD-Aided Downlink Multiuser MIMO-OFDM Systems
    Autorzy:
    Aust, S.
    Ahrens, A.
    Benavente-Peces, C.
    Powiązania:
    https://bibliotekanauki.pl/articles/227057.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    multiple-input multiple-output system
    orthogonal frequency division multiplexing
    singular value decomposition
    bit allocation
    wireless transmission
    Opis:
    Multicarrier transmission such as OFDM (orthogonal frequency division multiplexing) is an established technique for radio transmission systems and it can be considered as a promising approach for next generation wireless systems. However, in order to comply with the demand on increasing available data rates in particular in wireless technologies, systems with multiple transmit and receive antennas, also called MIMO (multiple-input multiple-output) systems, have become indispensable for future generations of wireless systems. Due to the strongly increasing demand in high-data rate transmission systems, frequency non-selective MIMO links have reached a state of maturity and frequency selective MIMO links are in the focus of interest. In this field, the combination of MIMO transmission and OFDM can be considered as an essential part of fulfilling the requirements of future generations of wireless systems. However, single-user scenarios have reached a state of maturity. By contrast multiple users' scenarios require substantial further research, where in comparison to ZF (zero-forcing) multiuser transmission techniques, the individual user's channel characteristics are taken into consideration in this contribution. The performed joint optimization of the number of activated MIMO layers and the number of transmitted bits per subcarrier shows that not necessarily all user-specific MIMO layers per subcarrier have to be activated in order to minimize the overall BER under the constraint of a given fixed data throughput.
    Źródło:
    International Journal of Electronics and Telecommunications; 2011, 57, 4; 459-464
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance Enhancement of Coherent Optical OFDM System Using LMS Algorithm
    Autorzy:
    Bharti, Manisha
    Powiązania:
    https://bibliotekanauki.pl/articles/308124.pdf
    Data publikacji:
    2020
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    coherent optical-orthogonal frequency division multiplexing (CO-OFDM)
    common phase error
    east means quare (LMS)
    chase noise
    Opis:
    Instability of the local oscillator causes phase noise – a phenomenon that is a disadvantage and is considered to be a major obstacle in the functioning of coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. An attempt has been made in this paper to reduce the effects of common phase errors generated by phase noise. In this paper, a least mean square (LMS) based algorithm is proposed for estimation of phase noise. Using this proposed algorithm, the major problem of phase ambiguity caused by cycle slip is avoided and the bit error rate is greatly improved. Further, there is no requirement for modifying the frame structure of OFDM using this algorithm. A CO-OFDM system with the 8-PSK technique is used to implement the algorithm concerned. Furthermore, the algorithm, using the 8-PSK modulation technique, is analyzed and compared with the existing QPSK technique and with other algorithms. The investigations reveal that 8-PSK outperforms existing LMS algorithms using other techniques and significantly reduces the bit error rate.
    Źródło:
    Journal of Telecommunications and Information Technology; 2020, 1; 1-5
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of hybrid PDM-4QAM-OFDM for inter-satellite/mechatronic telecommunication using FSO system
    Autorzy:
    Singh, Shivmanmeet
    Grewal, Narwant Singh
    Kaur, Baljeet
    Powiązania:
    https://bibliotekanauki.pl/articles/27315699.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
    Tematy:
    inter-satellite optical wireless communication
    IsOWC
    mechatronic telecommunication
    polarisation division multiplexing-quadrature amplitude modulation-orthogonal frequency division multiplexing
    PDM-4QAM-OFDM
    Opis:
    In this paper, the designing and simulation of 400 Gbps polarisation division multiplexingquadrature amplitude modulation-orthogonal frequency division multiplexing (PDM- 4QAM-OFDM)-based inter-satellite optical wireless communication (IsOWC)/mechatronic telecommunication system for improving the link information carrying capacity was carried out. With quadrature amplitude modulation (QAM) encoding, the performance of the executed system has been addressed using metrics such as signal to noise ratio (SNR) and total received power (RP). The performance with suggested system has been examined in relation to the effects of various factors such as operating wavelength, transmission power, and receiving pointing error angle. Moreover, a better identification method for improving connection reach between mechatronic devices/satellites has been revealed in this study. A performance comparison of the proposed system with other implemented approaches has been made in the final step.
    Źródło:
    Opto-Electronics Review; 2023, 31, 3; art. no. e147036
    1230-3402
    Pojawia się w:
    Opto-Electronics Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance analysis of DFT-S-OFDM waveform for Li-Fi systems
    Autorzy:
    Hussin, S.
    Shalaby, E. Mansour
    Powiązania:
    https://bibliotekanauki.pl/articles/2063891.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
    Tematy:
    light-fidelity
    visible light communications
    orthogonal frequency division multiplexing
    discrete Fourier transform spread
    peak-to-average power ratio
    Opis:
    In this paper, the effect of an indoor visible light communication channel is studied. Moreover, the analysis of the received power distribution of the photodiode in the line of sight and the first reflection of the channel without line of sight with several parameters is simulated. Two different waveforms are explained in detail. Orthogonal frequency division multiplexing has been widely adopted in radio frequency and optical communication systems. One of the most important disadvantages of the orthogonal frequency division multiplexing signal is the high peak-to-average power ratio. Therefore, it is important to minimize the peak-to-average power ratio in the visible light communication systems more than in radio-frequency wireless applications. In the visible light communication systems, the high peak-to-average power ratio produces a high DC bias which reduces power efficiency of the system. A discrete Fourier transform spread orthogonal frequency division multiplexing is proposed to be used in wireless communication systems; its ability to minimize peak-to-average power ratio has been tested. The analysis of two different subcarrier allocation methods for the discrete Fourier transform-spread subcarriers, as well as the examination of two distinct subcarrier allocation strategies, distributed and localized mapping, are investigated and studied. The effects of an accurate new sub-band mapping for the localized discrete Fourier transform spread orthogonal frequency division multiplexing scheme are presented in this paper. The light-fidelity system performance of the orthogonal frequency division multiplexing and discrete Fourier transform spread orthogonal frequency division multiplexing with different sub-mapping techniques are simulated with Matlab™. A system performance size of bit error rate and peak-to-average power ratio are obtained, as well.
    Źródło:
    Opto-Electronics Review; 2021, 29, 4; 167--174
    1230-3402
    Pojawia się w:
    Opto-Electronics Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigation of Vehicular S-LSTM NOMA Over Time Selective Nakagami-m Fading with Imperfect CSI
    Autorzy:
    Shankar, Ravi
    Chaudhary, Bhanu Pratap
    Mishra, Ritesh Kumar
    Powiązania:
    https://bibliotekanauki.pl/articles/2174454.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Łączności - Państwowy Instytut Badawczy
    Tematy:
    inter-symbol interference
    MIMO
    NOMA
    orthogonal frequency division multiplexing
    OFDM
    S-LSTM
    zero-mean circularly symmetric complex Gaussian
    ZM-CSCG
    Opis:
    In this paper, the performance of a deep learningbased multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) system is investigated for 5G radio communication networks. We consider independent and identically distributed (i.i.d.) Nakagami-m fading links to prove that when using MIMO with the NOMA system, the outage probability (OP) and end-to-end symbol error rate (SER) improve, even in the presence of imperfect channel state information (CSI) and successive interference cancellation (SIC) errors. Furthermore, the stacked long short-term memory (S-LSTM) algorithm is employed to improve the system’s performance, even under time-selective channel conditions and in the presence of terminal’s mobility. For vehicular NOMA networks, OP, SER, and ergodic sum rate have been formulated. Simulations show that an S-LSTM-based DL-NOMA receiver outperforms least square (LS) and minimum mean square error (MMSE) receivers. Furthermore, it has been discovered that the performance of the end-to-end system degrades with the growing amount of node mobility, or if CSI knowledge remains poor. Simulated curves are in close agreement with the analytical results.
    Źródło:
    Journal of Telecommunications and Information Technology; 2022, 4; 47--59
    1509-4553
    1899-8852
    Pojawia się w:
    Journal of Telecommunications and Information Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of a high-speed hybrid OAM-OFDM-MDM multiplexed coherent FSO system under desert conditions
    Autorzy:
    Sinha, Shivaji
    Kumar, Chakresh
    Powiązania:
    https://bibliotekanauki.pl/articles/27310107.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    atmospheric attenuation
    bit error rate
    BER
    orbital angular momentum
    OAM
    optical signal-to-noise ratio
    OSNR
    orthogonal frequency division multiplexing
    OFDM
    quadrature amplitude modulation
    QAM
    transmission range
    Opis:
    To meet the needs of future wireless optical networks, this paper introduces a high-speed, hybrid multiplexed, coherent free-space optical (FSO) communication system that integrates an orbital angular momentum (OAM) multiplexed signal with an orthogonal frequency division multiplexing (OFDM) technique. Two independent QAM polarized beams, each carrying in-phase and quadrature (I/Q) phase 16-QAM-OFDM modulated data, are combined using mode division multiplexing (MDM) to increase the capacity of the proposed system. The reason of choosing OFDM is its capability to support higher data rate, and mitigating intersymbol interference (ISI). The signal is detected using a coherent detection-based digital signal processing (DSP) algorithm at the receiver end. The proposed hybrid FSO system is evaluated in low and heavy dust environments using bit error rate (BER), link distance, optical signal-to-noise ratio (OSNR), and received optical power performance matrices. The simulation results demonstrate the successful transmission of a 120 Gb/s single carrier over the longest link ranges of 1.5 and 0.40 km, respectively, under low and heavy dust weather environments below the signal degradation threshold value (forward error correction (FEC) limit) of BER 2.2 × 10–3 in strong turbulent conditions.
    Źródło:
    Optica Applicata; 2023, 53, 3; 431--445
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stealthy Information Transmission in the Terrestrial GMDSS Radiotelephone Communication
    Autorzy:
    Shishkin, A. V.
    Koshevoy, V. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/116053.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    Global Maritime Distress and Safety System (GMDSS) Audio Watermarking (AW)
    Automatic Radio Telephone Identification System (ARTIS) Very High Frequency (VHF)
    Terrestrial GMDSS Radiotelephone Communication Radiocommunication
    Intersymbol Interference (ISI)
    Orthogonal Frequency Division Multiplexing (OFDM)
    Opis:
    Audio watermarking (AW) technology is considered for stealthy information embedding directly into audio signal. Inherent in analog radiotelephone channel interferences against watermarks are analyzed. Robust encoding/decoding algorithms are presented and appropriate project of AW system named as Automatic Radio Telephone Identification System (ARTIS) is proposed. Experimental results for the practical VHF radio channel are presented. Relating on processing complexity the designed system enables imperceptibly transmit data on a rate up to 260 bit/sec in the standard VHF radio channel. ARTIS provides the full compatibility with the existing radio installation, and doesn’t require replacement of standard VHF transceivers and operational procedures. Besides, automatic identification the system may be used in the special applications, for example, under the threat of terrorist attack; generally contributes to navigation safety and information security.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2013, 7, 4; 541-548
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance evaluation of UFMC-based VLC systems using a modified SLM technique
    Autorzy:
    Mansour Shalaby, E.
    Dessouky, M.
    Hussin, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1818194.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
    Tematy:
    universal filtered multi-carrier
    orthogonal frequency division
    multiplexing
    peak-to-average power ratio
    selected-mapping
    discrete Hartley transform precoding
    Opis:
    Universal filtered multi-carrier (UFMC) is being studied as the favourable waveforms supporting the visible light communication broadcasting systems. However, the UFMC system faces a serious performance degradation on the transmitter side due to its high peak-to-average power ratio (PAPR). High PAPR of the signal is an analytical intention parameter for mobile networks, and it is necessary to minimize it as much as possible. This paper focuses on the PAPR reduction of the UFMC scheme. An efficient hybrid method of the PAPR reduction has been proposed and analysed through the Matlab™ simulation. The proposed hybrid scheme consists of a mixture of the selected-mapping method and the discrete Hartley transform precoding for a UFMC system (SLM-DHT-P-UFMC). The simulation results show that the proposed hybrid system has a better PAPR reduction performance compared to traditional SLM-UFMC and DHT-P-UFMC systems. Hence, LM-DHT-P-UFMC is considered to be the suggested scheme in visible light communication broadcasting systems.
    Źródło:
    Opto-Electronics Review; 2021, 29, 3; 85--90
    1230-3402
    Pojawia się w:
    Opto-Electronics Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Performance evaluation of UFMC-based VLC systems using a modified SLM technique
    Autorzy:
    Mansour Shalaby, E.
    Dessouky, M.
    Hussin, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1818201.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
    Tematy:
    universal filtered multi-carrier
    orthogonal frequency division
    multiplexing
    peak-to-average power ratio
    selected-mapping
    discrete Hartley transform precoding
    Opis:
    Universal filtered multi-carrier (UFMC) is being studied as the favourable waveforms supporting the visible light communication broadcasting systems. However, the UFMC system faces a serious performance degradation on the transmitter side due to its high peak-to-average power ratio (PAPR). High PAPR of the signal is an analytical intention parameter for mobile networks, and it is necessary to minimize it as much as possible. This paper focuses on the PAPR reduction of the UFMC scheme. An efficient hybrid method of the PAPR reduction has been proposed and analysed through the Matlab™ simulation. The proposed hybrid scheme consists of a mixture of the selected-mapping method and the discrete Hartley transform precoding for a UFMC system (SLM-DHT-P-UFMC). The simulation results show that the proposed hybrid system has a better PAPR reduction performance compared to traditional SLM-UFMC and DHT-P-UFMC systems. Hence, LM-DHT-P-UFMC is considered to be the suggested scheme in visible light communication broadcasting systems.
    Źródło:
    Opto-Electronics Review; 2021, 29, 3; 85--90
    1230-3402
    Pojawia się w:
    Opto-Electronics Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-14 z 14

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