Syed Alwee Aljunid Syed Junid
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Syed Alwee Aljunid Syed Junid
Official Name
Syed Alwee Aljunid, Syed Junid
Alternative Name
Aljunid, S.
Aljunid, Syed Alwi
Aljunid, Syed A.
Aljunid, S. Alwee
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Scopus Author ID
56000543300

Research Output
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Modeling of satellite-to-underwater integrated FSO-PON system using NOMA-VLC

2023 , Vivek Arya , Meet Kumari , Hamza Mohammed Ridha Al-Khafaji , Syed Alwee Aljunid Syed Junid

In recent years, optical wireless communication has promised several benefits over radio frequency communication in atmospheric, deep space and underwater communications. Satellite-to-underwater communication technology can be applied to commercial, naval, scientific and engineering operations because of its high data rate, high security, long-reach and low cost. In this paper, a high-speed, long-reach integrated free space optics (FSO)-passive optical network (PON) system using non-orthogonal multiple access visible light communication (NOMA-VLC) is proposed. It poses a 10/2.5 Gbps per channel bit rate for satellite-to-underwater applications. Numerically calculated results provide the splitter power budget of −35 dBm in the downlink and −32 dBm in the uplink. Additionally, a receiver sensitivity of 23 dB in the downlink and 10 dB in the uplink direction can be obtained in the system using a modified new zero cross-correlation (MNZCC) code under clear environment conditions. Again, the simulative analyses indicate that the suggested system supports 290 underwater devices successfully and offers a high 10 dBm signal-to-noise ratio over 10 km FSO, 100 km fiber and 5 m VLC range. Moreover, it provides a signal-to-noise ratio of 39 dB, with −9 dBm received optical power at 300 fields of view under fiber-wireless channels’ impairments. We argue that the suggested system is a symmetric system adapted to different link distances and which offers improved receiver sensitivity and high received optical power at a 10−9 bit error rate (BER). The comparative analysis shows the advantages of the suggested system over previously reported works.

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Optical Code Division Multiple Access (OCDMA): Technology for the Future

2014 , Syed Alwee Aljunid Syed Junid

The explosive growth of bandwidth demand, together with advances in the latest communication services and emerging applications has inspired a huge interest in application of code division multiple access (CDMA) techniques in optical network. The major interference factor in optical CDMA (OCDMA) is to overcome the multiple access interference (MAI) noise which induces the occurrence of bit error rate. Ideal code property with minimum cross-correlation will mitigate MAI, reduce phase induced intensity noise (PIIN) and expand code scalability. Current research on OCDMA is devoted towards developing new OCDMA technologies that can suit the future generation of high transmission capacity optical network.

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Two dimensional (2D) OCDMA encoder-decoder for various industrial application

2021-12 , Syed Alwee Aljunid Syed Junid , Mohd Arif Anuar Mohd Salleh , A A M Ismail , ND Keraf , R Matem , Mohd Rashidi Che Beson , Norshamsuri Ali @ Hasim , Mohd Shafiq Amirul , Rosdisham Endut , Nor Azura Malini Ahmad Hambali

Future telecommunication systems and networks are expected to provide a variety of integrated broadband services to the customers. There has been a tremendous interest in applying Code Division Multiple Access (CDMA) techniques to fiber optic communication systems. This technique is one of the multiple access schemes that is becoming popular because of the flexibility in the allocation of channels, ability to operate asynchronously, enhanced privacy and increased capacity in bursty networks. This project is focusing on designing 2D OCDMA system with the hardware implementation of design using FPGA. The coding techniques in OCDMA are time versus wavelength and amplitude versus phase. 2D OCDMA coding incorporates both wavelength selection and time distribution. The data bit would be encoded as consecutive chips with various wavelengths. The code architecture seeks to produce codes with high autocorrelation and low cross-correlation properties. Code length is an essential aspect of code and device architecture for coding characteristics. The hardware implementation of the system is designed by using FPGA De1-SoC. The FPGA have the abilities to enhance the transmission of data to the receiver in a short period of time. The performance of 2D OCDMA system is expected to surpass 1D OCDMA system in terms of BER and the number of simultaneous users that can be supported. The system encoder and decoder were designed using optical switch, splitter, combiner and modulator. The performance of 2D OCDMA system in terms of time spreading and wavelength spreading is also compared which shown a huge difference in the results. The best performance of the system is when the number of wavelength (M) is fixed to 18 and the number of times spreading (N) is 31 which can support 350 more simultaneous users.

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