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Wyszukujesz frazę "Abdullah, N." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Implementation of Selected Spectrum Sensing Systems for Cognitive Radio Networks using FPGA Platform
Autorzy:
Abdullah, H. N.
Abed, H. S.
Powiązania:
https://bibliotekanauki.pl/articles/958080.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
cognitive radio
energy consumption
energy detection
FPGA
Opis:
The energy efficient spectrum sensing method is very important in cognitive radio (CR), since high power drain may limit its implementation in mobile applications. The spectrum sensing feature consumes more energy than other functional blocks, as it depends on continuous detection of the presence or absence of the primary user (PU). In this paper, we proposed two methods to reduce energy consumption of the spectrum sensing feature. The first is of a single stage variety with a reduced number of sensed samples. The other uses two stages. The first stage performs coarse sensing for many subchannels, and the best subchannel is forwarded for fine sensing in the second stage. The performance of the proposed methods is evaluated in AWGN channel and compared with the existing approach. The proposed methods are simulated using Matlab and ModelSim and are then hardware implemented using the Altera Cyclone II FPGA board. Simulation results show that the proposed methods offer an improvement in energy consumption with an acceptable reduction in the probability of detection. At Eb/N0 Eb/N0 Eb/N0 of 0 dB, the energy consumption is reduced by 50% and 72% in the first and second proposed method, respectively, compared to the traditional method (100% sensing).
Źródło:
Journal of Telecommunications and Information Technology; 2018, 4; 81-87
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design Low Complexity SCMA Codebook Using Arnold’s Cat Map
Autorzy:
Mohamed, Sura S.
Abdullah, Hikmat N.
Powiązania:
https://bibliotekanauki.pl/articles/2174447.pdf
Data publikacji:
2022
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
chaotic interleaving
codebook design
dimension rotation
Euclidean distance
sparse code multiple access
Opis:
In 5G wireless communications, sparse code multiple access (SCMA) – a multi-dimensional codebook based on a specific category of the non-orthogonal multiple access (NOMA) technique - enables many users to share non-orthogonal resource components with a low level of detection complexity. The multi-dimensional SCMA (MD-SCMA) codebook design presented in this study is based on the constellation rotation and interleaving method. Initially, a subset of the lattice Z 2 is used to form the mother constellation’s initial dimension. The first dimension is then rotated to produce other dimensions. Additionally, interleaving is employed for even dimensions to enhance fading channel performance. Arnold’s chaotic cat map is proposed as the interleaving method to reduce computational complexity. Performance of the SCMA codebook based on interleaving is evaluated by comparing it with selected codebooks for SCMA multiplexing. The metrics used for performance evaluation purposes include bit error rate (BER), peak to average power ratio (PAPR), and minimum Euclidean distance (MED), as well as complexity. The results demonstrate that the suggested codebook with chaotic interleaving offers performance that is equivalent to that of the conventional codebook based on interleaving. It is characterized by lower MED and higher BER compared to computer-generated and 16-star QAM codebook design approaches, but its complexity is lower than that of the conventional codebook based on interleaving.
Źródło:
Journal of Telecommunications and Information Technology; 2022, 4; 13--20
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CG-SCMA Codebook Design Based on Maximized Euclidian Distance
Autorzy:
Mohamed, Sura S.
Abdullah, Hikmat N.
Powiązania:
https://bibliotekanauki.pl/articles/2200958.pdf
Data publikacji:
2023
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
codebook
Euclidian distance
MPA
multiple access
sparse code
Opis:
Sparse code multiple access (SCMA) is a multi-dimensional codebook based on a class of non-orthogonal multiple access (NOMA) technologies enabling the delivery of non-orthogonal resource elements to numerous users in 5G wireless communications without increasing complexity. This paper proposes a computer-generated sparse code multiple access (CG-SCMA) technique, where the minimum Euclidian distance (MED) of a star 16-point quadrature amplitude modulation is maximized by CG-SCMA, thus creating a complex SCMA codebook based on optimizing the difference between the first and other radiuses over rotated constellations. To specify the most suitable values for this constellation, it is divided into four sub-constellations using trellis coded modulation (TCM) in an effort to optimize MED. The new codebook has four sub-constellations with MED values of 3.85, 2.26, 2.26, and 3.85, respectively. Application of the message passing algorithm (MPA) ensures low complexity of the decoding process
Źródło:
Journal of Telecommunications and Information Technology; 2023, 1; 18--24
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
    Wyświetlanie 1-5 z 5

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