Norizan Mohamed Nawawi
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Norizan Mohamed Nawawi
Official Name
Norizan, Mohamed Nawawi
Alternative Name
Nawawi, N. M.
Nawawi, Norizan Binti Mohamed
Nawawi, Norizan
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Scopus Author ID
26967861100

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  • Publication
    Implementation of particle swarm optimization and genetic algorithms to tackle the PAPR problem of OFDM system
    (IOP Publishing, 2020)
    A Abdalmunam
    ;
    Anuar Mat Safar
    ;
    MN Junta
    ;
    Norizan Mohamed Nawawi
    ;
    A Noori
    A multi-carrier modulation technique, which represented in this paper as orthogonal-frequency-division-multiplexing (OFDM), ensured wireless high-speed data transmission. The transmission of modulated symbols uses a large number of subcarriers in the OFDM system. Consequently, the OFDM signals have an extended dynamic range, or a high output power peak envelope fluctuation or high PAPR. To mitigate the PAPR, in this paper, we implement two algorithms to reduce the output power envelope fluctuation of the OFDM system, namely PSO and GA. Also, the PTS method and PAPR in OFDM systems difficulty described briefly. We present an OFDM system through the use of conventional PTS based on PSO and GA. The simulation result shows that both evolutionary approaches outperform the conventional PTS OFDM in-terms of reducing the Peak-to-Average-Power-Ratio (PAPR). Furthermore, the performance of the PSO algorithm is found to be better than GA in-terms of its simplicity and the time execution. On the other hand, the GA algorithm outperforms the PSO and the conventional OFDM, in terms of the PAPR reduction.
  • Publication
    AI-powered MMI fiber sensors for wide-range refractive index detection using neural networks algorithm
    (Elsevier, 2025-03)
    Nurul Farah Adilla Zaidi
    ;
    Muhammad Yusof Mohd Noor
    ;
    Nur Najahatul Huda Saris
    ;
    Mohd Rashidi Salim
    ;
    Sumiaty Ambran
    ;
    Azizul Azizan
    ;
    Raja Kamarulzaman Raja Ibrahim
    ;
    Fauzan Ahmad
    ;
    Nurul Ashikin Daud
    ;
    Norazida Ali
    ;
    Norizan Mohamed Nawawi
    ;
    Ian Yulianti
    ;
    Gang-Ding Peng
    This research presents an artificial intelligence (AI)-driven machine learning (ML) approach for accurately measuring refractive index (RI) values across both lower and higher regimes than the fiber material's RI, using a simple single multimode interference (MMI) fiber sensor. The sensor configuration consists of a no-core fiber (NCF) segment between two single-mode fiber (SMF) sections. A Bilayer Neural Network (BNN) regression model is employed to predict both low refractive index (LRI) and high refractive index (HRI) regimes, achieving a broad dynamic measurement range from 1.3000 RIU to 1.3900 RIU for LRI regime and from 1.4600 RIU to 1.5500 RIU for HRI regime. The model demonstrates 99.7% accuracy and a low root mean square error (RMSE) of 0.0044, ensuring that predicted RI values closely match actual measurements without any RI ambiguity. Furthermore, the all-silica NCF structure is inherently resistant to temperature fluctuations, enabling its deployment in environments with varying temperatures without requiring additional temperature compensation mechanisms.
      1
  • Publication
    High capacity of optical code division multiple access in visible light communication system using catenated OFDM modulation technique
    ( 2019)
    Norizan Mohamed Nawawi
    Visible light communication (VLC) system is a new technology as an alternative for crowded wireless communication using radio frequency spectrum. This technology offers unregulated, unlicensed and huge bandwidth to meet the growing demand in future indoor communication system. To date, the major challenge in VLC systems has been in improving transmission speed of VLC system with optimize bandwidth capacity. One of the method to improve spectral usage is using advanced modulation formats such as orthogonal frequency division multiplexing (OFDM). In this work, a new approach for modulation technique based on modification of conventional OFDM has been developed in VLC system which capable to improve the spectral efficiency and optimize the data rate. This work also contributes to the development of mathematical model of optical code division multiple access (OCDMA) based on zero cross correlation code (ZCC) using a new modulation technique. This combination demonstrates an efficient access control in backbone design network to enhance the channel capacity, to upgrade the system data rate and at same time to improve sensitivity of photodetector. In particular, this thesis begins with the construction of a new modulation technique, namely catenated-OFDM that is developed based on multiband OFDM. In order to fulfill the next generation demand for higher data rate system, conventional OFDM-VLC is modified to get the optimum performance. A new mathematical framework of this modulation technique to analyze SNR and BER performance in VLC system has been derived. Simulation are carried out to evaluate some parameters that are not included in the numerical analysis. Different selection of parameter values such as bit rates, number of bands, effective power and propagation distance will have different effect on the system performance. Validation of theoretical results and simulation results are also conducted. Numerical analysis shown that the catenated-OFDM outperforms conventional OFDM by five times spectral efficiency improvement and eight times spectral efficiency improvement at their five and eight number of bands respectively. It is also shown that the proposed catenated-OFDM design is working well even at very high bit rate of 15 Gbps. In the combination of OCDMA-VLC using catenated-OFDM, the theoretical analysis and simulation model are also developed to evaluate and analyze its performance. This system theoretically demonstrates cardinality enhancement with double-fold, triple-fold and quadruple increase in number of user for (Band=2), (Band=5) and (Band=8) respectively compared to previous OCDMA ZCC-VLC system design. This result reveals improvement in term of receiver sensitivity which the power penalty of 7.3 dB compared to previous work. In addition, this integration provides higher receiver sensitivity; an approximately –17.7 dBm with 8 number of weight and fixed code length of 20. It is also found that, to accommodate more user, the system requires higher effective power at the receiver. This results exhibit the feasibility of the scheme to be one powerful modulation technique as a candidate for future access network. Thus, with a larger capacity, high data rate and enhanced security the OCDMA-VLC based on catenated-OFDM is predicted to be new considerable for upcoming OCDMA-VLC mobile communication system design.
      2  23
  • Publication
    Indoor Navigation System for Vision Impairment People through Visible Light Communications
    ( 2020-03-20)
    Rithuan M.N.
    ;
    `Aini Syuhada Md Zain
    ;
    Norizan Mohamed Nawawi
    Indoor navigation is opportune for everyone, and it is particularly requisite for the visually impaired. The paper proposes an indoor navigation system for the Visually Impaired to attain audio output through visible light communications. The transmission of data occurs after identifying the person who has entered the room and the technology light fidelity is used for presenting information to the user. Light fidelity technology is used by the proposed system for the wider range of transmission of data. The usage of visible light for transmitting the data encompasses a wide variety of advantages and eliminates most problems of communication caused by the electromagnetic waves outside the visible spectrum. Light fidelity technology is an evolving branch of Optical Wireless Communication and can be beneficial in coming years for indoor communication because it can afford higher data rate transmission along with the capability to utilize additional users since it uses a broader spectrum bandwidth. The main idea of our project is to create internal navigation system by using Arduino software and Arduino hardware. The transmission of data can act as transceiver, where LED and solar cell are used as the medium to transmit and receive the data.
      6  46
  • 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