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Chen, Xing (2025) Research and implementation on optical wireless communication technologies. MPhil thesis, University of Nottingham.

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Abstract

Continuous global growth and increasing demand for wireless communication cause a shortage of radio frequency (RF) spectrum. Optical wireless communication (OWC) is expected to alleviate this looming spectrum crisis. Among OWC technologies, free space optic (FSO) and visible light communication (VLC) have rapidly become a research hot spot because of significant development and application prospects.

This study aims to investigate the characteristics of OWC technologies and offer theoretical support for enhancing the transmission performance. To achieve this goal, simulation models are set up, and better system parameters and modulation schemes are selected.

In the FSO model, an established modulation, absolute added correlative coding (AACC), is compared with four-level pulse amplitude modulation (4-PAM) in terms of transmission distance, eye diagram and bitrate. The results indicate that AACC transmits longer distance and at a higher bitrate than 4-PAM. Using the bit error rate (BER) with an estimation of 10-9, the transmission distance achieved by AACC is 1.12 km, compared to 1.09 km for 4-PAM. And the bitrate of AACC is 18.7 Gbit/s, while it of 4-PAM is 16.7 Gbit/s. From the above results, the AACC modulation gives an improvement of 3% in the distance and 12% in the bitrate compared to 4-PAM modulation. In indoor VLC model, simulation results like illumination distribution, received power, signal-to-noise ratio (SNR) and root-mean-square (RMS) delay are evaluated. The illumination distribution between one light emitting diode (LED) array and four LED arrays is compared. It shows that four LED displays provide more uniform illumination. And the received power in LOS channel and NLOS channel are analysed. It shows that the contribution of LOS channel is decisive for the received power, and the assistance of NLOS channel is concentrated near the walls. In addition to these simulation results, measure algorithms of indoor positioning system (IPS) based on the same model are also investigated. It provides an experimental foundation for the construction of a robust and high data rate light fidelity (Li-Fi) system as well as a more accurate IPS. With the continuous improvement of OWC technologies, a more efficient and secure wireless communication network will be widely used.

Item Type:	Thesis (University of Nottingham only) (MPhil)
Supervisors:	Khan, Nafizah
Keywords:	optical wireless communication (OWC); radio frequency (RF) spectrum; free space optic (FSO); visible light communication (VLC); spectrum crisis; transmission performance
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Faculties/Schools:	University of Nottingham, Malaysia > Faculty of Science and Engineering — Engineering > Department of Electrical and Electronic Engineering
Item ID:	79905
Depositing User:	Chen, Xing
Date Deposited:	08 Feb 2025 04:40
Last Modified:	08 Feb 2025 04:40
URI:	https://eprints.nottingham.ac.uk/id/eprint/79905

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