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Free-space optical (FSO) communication has become a focus of both study and commercial interest. FSO transfers data between sites in free space, typically the Earth's atmosphere or space, using laser-emitted light beams, in contrast to standard radio frequency (RF) wireless communication. The possibility for high data transmission speeds, the lack of licencing constraints, versatility, affordability, simplicity of deployment, and its environmentally friendly communication method which provides an alternative to crowded radio frequency-based communications are the driving forces behind this growing interest. To determine the feasibility of FSO communication in the cities of Alexandria and Aswan in Egypt, we utilized the micrometeorology model to analyze how weather conditions and atmospheric turbulence impact on FSO linkages based on real-time weather data. In both the winter and summer seasons, we evaluated the bit error rate, beam spreading, scintillation, and transmission range of FSO. Moreover, bit error rate performance was improved by the use of the multi-hop Decode and Forward relay. [ABSTRACT FROM AUTHOR]

This paper introduces a novel free space optics (FSO) communication system for future-generation high-speed networks. The proposed system integrates orbital angular momentum (OAM) modes with an optical code division multiple access (OCDMA) technique. Two OAM beams are used ( L G 0 , 0 and L G 0 , 10 ), each of which is used for transmitting three independent channels. Each channel is assigned by fixed right shift (FRS) codes and carries 10 Gbps of information data. The performance of the proposed model is evaluated under different foggy and dust storm conditions. Furthermore, the performance of two cities with different geographical locations, Alexandria city in Egypt and Srinagar city in India, is investigated to demonstrate its ability to be implemented in future generations. Bit error rate (BER), eye diagrams, received optical power (ROP), and channel capacity are used for studying the performance of the proposed system. The observed simulation results show successful transmission of 60 Gbps overall capacity with the longest propagation FSO range for Alexandria city, which is 1400 m. Because dust storms have a large attenuation when compared to different foggy conditions, the proposed model had the shortest propagation range of 315 m under low dust (LD), 105 m under moderate dust (MD), and 40 m under heavy dust (HD). Furthermore, the cloudy weather conditions that affect Srinagar city, which is considered a hilly area, make our suggested model achieve 1000 m. [ABSTRACT FROM AUTHOR]

Free space optical (FSO) communication is one of the recent promising new access technologies. FSO provides data transmission with high security and unlimited bandwidth with low cost of installation. Optical signal absorption and scattering are the two main factors of attenuation due to the terrestrial channel. Pointing error is a technical factor that causes attenuation of the signal which results from the misalignment of the transmitter and the receiver. This paper investigates the FSO performance for an atmospheric channel in Alexandria city, Egypt. The study covers the operating wavelength, modulation technique, receiver aperture diameter, and type of photodetector. The study considers the practical average of meteorological measurements for Alexandria city obtained from Egyptian Meteorological Unit. The system performance is evaluated by its bit error rate, signal-to-noise ratio, and the received power at different system parameters. The system is studied by simulation and experimentally using Optisystem ver. 15.2. It is found that the FSO system is so sensitive to the transmitter–receiver misalignment. However, the effect of thermal noise and background noise could not be neglected compared to the resulting pointing error due to the Mediterranean climate which is mainly characterized by high temperature and humidity. After this integrated parametric study for the system performance, we deduced the practical application availability for the system starting from low to higher data rates with respect to climate and system parameters. Therefore, one can ensure that the system can be used on a wider scale of customers. [ABSTRACT FROM AUTHOR]