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

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A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems

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.

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Performance enhancement of LACO-OFDM BER and PAPR using a K-means algorithm for a VLC system

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.

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