Temat: OFDM - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

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

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