Citation

Ghanem, Mahran and Amphawan, Angela and Mohd Ramly, Athirah and Neo, Tse-Kian and Ahmad Blya, Nur Ily Syuhada (2025) Sparse code multiple access with hermite-gaussian spatial modes in free space optical communications. In: 4th International Conference on Computer, Information Technology and Intelligent Computing, CITIC 2024, 23 July 2024 - 25 July 2024, Virtual, Online.

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Abstract

Free space optical (FSO) communications offer license-free, rapid deployment of high-speed communications for expanding the coverage and capacity in congested public spaces through smaller cells. Despite the inherent security of FSO systems, optical data propagated over public spaces is susceptible to the presence of unauthorized eavesdroppers trying to extract information from a genuine user. In pursuit of enhanced confidentiality of data transmission, physical layer security represents a previously untapped commodity, in contrast to existing higher-layer encryption. In this paper, Hermite-Gaussian (HG) beams are leveraged for physical layer security through sparse code multiple access (SCMA) for a four-channel FSO system. Previous resource elements for SCMA-based FSO systems were based on orthogonal frequency division multiplexing, wavelength division multiplexing and power domain nonorthogonal multiple access. In contrast, in this work, for the first time, the data from each user is inscribed based on transmitted binary phase shift keying symbols from a SCMA codebook, encoded on individual HG beams. The effectiveness of the suggested system is assessed by numerical simulations to obtain the bit error rate (BER), packet error rate (PER), Euclidean distance and independence over a log normal-distributed FSO channel, under weak, moderate and high atmospheric turbulence conditions. Consequently, satisfactory BER, PER, Euclidean distance and independence values are achieved for the four channels, demonstrating that the proposed system is secure and resistant to eavesdropping attacks. The new physical-layer HG SCMA-based FSO system has valuable future applications for multi-user sensory encoding for secure data transmission in cyber-physical systems.

Item Type:	Conference or Workshop Item (Paper)
Uncontrolled Keywords:	Atmospheric dynamics, Data processing, Optical communications, Wavelength division multiplexing, Telecommunications engineering, Probability theory, Physics education research
Subjects:	Q Science > QC Physics > QC851-999 Meteorology. Climatology Including the earth's atmosphere
Divisions:	Faculty of Creative Multimedia (FCM)
Depositing User:	Nurin Syazwani Azmi
Date Deposited:	10 Dec 2025 08:40
Last Modified:	10 Dec 2025 08:40
URII:	http://shdl.mmu.edu.my/id/eprint/15055

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