Anuar Mat Safar
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Preferred name
Anuar Mat Safar
Official Name
Anuar, Mat Safar
Alternative Name
Mat Safar, Anuar
Main Affiliation
Scopus Author ID
57193311430
Researcher ID
IYF-6674-2023

Research Output

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  • Publication
    A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems
    (De Gruyter, 2023)
    Aymen Abdalmunam Hameed
    ;
    Anuar Mat Safar
    ;
    Montadar Abas
    ;
    Junita Mohd Nordin
    ;
    Norizan Mohamed Nawawi
    In this paper, we propose a new adaptive layered asymmetrically-clipped optical orthogonal frequency division multiplexing (ALACO-OFDM) technique as a method to improve the spectral efficiency of optical system, especially visible light communication (VLC). Particle swarm optimisation (PSO)-based LACO-OFDM method is used for this purpose and the channel capacities are studied. Simulations using variable layers are carried out to validate the theoretical steps. The simulation results indicate that the ALACO-OFDM technique has significantly improve the spectral efficiency compared to previous techniques such as ACO-OFDM. Moreover, it is shown that channel capacities of different layers are significantly improved when electrical power is increased.
      2  25
  • Publication
    Performance enhancement of LACO-OFDM BER and PAPR using a K-means algorithm for a VLC system
    (Optica Publishing Group, 2023)
    Junita Mohd Nordin
    ;
    Aymen Abdalmunam Hameed
    ;
    Anuar Mat Safar
    ;
    Norizan Mohamed Nawawi
    Layered asymmetrical clipped optical-orthogonal frequency division multiplexing (LACO-OFDM) enhances spectral efficiency by mandating the use of a K-means algorithm in LACO-OFDM (KLACO-OFDM), which enables efficiency gains to nearly double by modulating odd and even subcarriers. The traditional receiver is not sufficiently sophisticated enough to exploit the full potential of LACO-OFDM, thereby restricting its performance. In this paper, a K-means algorithm was used to increase the spectral efficiency of LACO-OFDM by integrating machine learning to cluster the inward signal such that the original locations of the received constellations can be retrieved. A K-means algorithm is used for assigning the received constellation points into their clusters of the ordinary quadrature amplitude modulator constellation points. The new mathematical framework in the proposed scheme is structured to analyze the PAPR and BER performance of LACO-OFDM systems that have been derived. The K-means algorithm development in LACO-OFDM (KLACO-OFDM) has also reduced the intersymbol interference, hence improving the spectral efficiency of LACO-OFDM compared with the conventional system in visible light communication (VLC) systems. BER gains were about 1.2–1.6 dB at 10−3 BER value, which rises from 1.4 to 2 dB for a 10−4 BER value because a lower BER facilitates precise estimation.
      1  11
  • Publication
    Implementation of particle swarm optimization based ICF technique to reduce the PAPR of ACO-OFDM
    (Walter de Gruyter GmbH, 2023)
    Aymen Abdalmunam
    ;
    Anuar Mat Safar
    ;
    Junita Mohd Nordin
    ;
    Hussein Sarhan
    ;
    Sara A. Alhashm
    ;
    Ather A. Ali
    Orthogonal frequency division multiplexing (OFDM) is advantageous in terms of the spectral efficiency it offers. However, in OFDM, the bandwidth-efficient multicarrier modulation (MM) is limited by the peak-to-average power (PAPR) problem. Iterative clipping and filtering (ICF) method has been used in this work to address such issue. The ICF is regarded as a practical scheme that has become widely accepted and used due to the fact that it is characterized by low computational complexity. This method is also easily implemented, characterized by non-expansion of bandwidth, and it does not require the support to the receiver side during implementation. Nevertheless, the significant of this work is on further improvement where the method involves the iterative clipping of the same signals with a fixed clipping threshold (CT) in every clipping operation. Particle swarm optimization based ICF-OFDM, which is proposed in this research work, literally finds the most suitable clipping ratio, that eventually solves the problem of output power instability. Subsequently, the proposed method is implemented with asymmetrical clipped optical OFDM (ACO-OFDM) to validate the proposed method through the use of Matlab simulation. The PAPR reduction of the proposed method is then compared with the PAPR of the Hartley transform (DHT)-based ACO-OFDM and the traditional ACO-OFDM and DCO-OFDM. The best BER performance has been investigated via two modulation index. Results indicate that our method outperforms the counterparts in term of PAPR reduction and BER performance.