Temat: Chaos - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Chaotic-based Orthogonal Frequency Division Multiplexing with Index Modulation
Autorzy:: Hussien, Sura H.
Abdullah, Hamsa A.
Powiązania:: https://bibliotekanauki.pl/articles/2174449.pdf
Data publikacji:: 2022
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: AWGN
chaos communications
DCSK
index modulation
Opis:: Orthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of the available transmit entities. Thanks to such an approach, it offers a novel method for the transmission of extra data bits. Recent years have seen a great interest in chaos-based communications. The spectrum-spreading signals used in chaotic signal modulation technologies are orthogonal to the existing mixed signals. This paper presents how well a non-coherent differential chaos shift keying communication system performs across an AWGN. Different types of detection methods are simulated, bit error rate and power spectral density are calculated and then compared with standard OFDM with index modulation. The results of simulations concerning the performance of a DCSK system, adding to the security of the proposed solution and offering a comparable bit error rate performance, are presented in the paper as well.
Źródło:: Journal of Telecommunications and Information Technology; 2022, 4; 33--38
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Performance Enhancement of Chaotic Error Correction Coding Using Consecutive Sequences
Autorzy:: Sahar, Asaad H.
Abdullah, Hikmat N.
Saed, Thamir R.
Powiązania:: https://bibliotekanauki.pl/articles/24200739.pdf
Data publikacji:: 2023
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: chaos communication
DCSK modulation
error correction
suboptimal receiver
Opis:: The use of chaotic dynamics for error correction is the subject of extensive research, as the approach allows to avoid the use of redundant data. This work proposes a new technique for non-coherent chaos communications for modifying error-correction depending on chaotic dynamics. In the proposed system, there are two consecutive sequences created from a comparable chaotic map, with the second series being created as the latest value of the initial one. Generation of a sequential chaotic sequence with a comparable chaotic dynamic delivers additional information to the receiver, allowing it to appropriately recover information and, hence, facilitate the receiver’s bit-error performance. For error correction and for detecting the symbol that is transmitted, a suboptimal technique based on the nearest distance between chaotic map trajectories over the n-dimensional sequence received is utilized. Simulation results show that the proposed error correction approach improves Eb/N0 as the dimension of the trajectory map increases, indicating that the method improves overall error correction performance. With the dimension of 4, a gain of 0.8 dB in Eb/N0 is achieved compared with an approach without any error-correcting schemes, at the bit-error probability of 10−3.
Źródło:: Journal of Telecommunications and Information Technology; 2023, 2; 10--16
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:: Channel Identification Using Chaos for an Uplink/Downlink Multicarrier Code Division Multiple Access System
Autorzy:: Frikel, M.
Safi, S.
Targui, B.
M'Saad, M.
Powiązania:: https://bibliotekanauki.pl/articles/308067.pdf
Data publikacji:: 2010
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: channel identification
chaos code
equalization
MC-CDMA system
Opis:: A scheme of chaotic spreading sequence for multicarrier code division multiple access system (MC-CDMA) iproposed to estimate the transmission channel. This systespreads spectrum and identifies the channel, simultaneously. The proposed scheme uses a chaotic sequence generated by a logistic map as a training signal and estimate channel parameters according to dynamics of the chaotic sequence. Encoding data by chaotic sequences is first built and then the orthogonal codes are used to spread the encrypted data for multiusers scheme. At the reception, first the channel parameters are identified using a training chaotic sequence in order to equalize the received data, and then the encrypted information is decoded for the desired user. The studies reveal that the proposed system (chaos plus orthogonal codes) significantly outperforms the Walsh-Hadamard code spreading in MC-CDMA system. The performance of the system is considered in the multiuser case by means of simulation. The simulation result shows that the proposed chaotic code spreading approach for channel identification achieves significant improvement in the channel identification, comparing to using others training sequence or the least square method.
Źródło:: Journal of Telecommunications and Information Technology; 2010, 1; 48-54
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: A study on fractal dimensions and convergence in fuzzy control systems
Autorzy:: Schuster, A.
Blackburn, W.
Prieto, M.S.
Powiązania:: https://bibliotekanauki.pl/articles/309243.pdf
Data publikacji:: 2002
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: fuzzy control systems
chaos theory
convergence
fractal dimension
Opis:: This paper addresses a problem in the area of intelligent, knowledge-based systems, namely the generation of knowledge, by presenting a proposal for the automation of this task. The proposed approach is limited however by focusing on fuzzy control systems (FCSs). Results obtained from different experimental investigations indicate the potential of the approach.
Źródło:: Journal of Telecommunications and Information Technology; 2002, 3; 30-36
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: An Improved M-ary Modulation Scheme Based on Chaotic Dynamics
Autorzy:: Abdullah, Hikmat N.
Sahar, Asaad H.
Saeed, Thamir R.
Powiązania:: https://bibliotekanauki.pl/articles/958105.pdf
Data publikacji:: 2019
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: chaos
M-ary modulation
non-coherent detection
zigzag map
Opis:: This paper proposes an improved chaos-based M-ary modulation system. It reproduces deterministic chaotic dynamics to create M-ary non-coherent modulation. The proposed modulation system transmits data using autonomous chaotic sequences. It separates the chaotic dynamics through the use of interleavers and realigns them through the use deinterleavers. The simulation results show that the improved scheme overperforms its traditional counterpart. The degree of improvement grows as the M-ary order is increased, with a penalty of increased system complexity.
Źródło:: Journal of Telecommunications and Information Technology; 2019, 4; 13-19
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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