# Next-Generation Dual Transceiver FSO Communication System for High-Speed Trains in Neon Smart City
## 1 Introduction
Neom's ambitious plans encompass the implementation of a high-speed railway system, known as the SPINE or Connector, within its urban framework. This extensive transportation network will stretch over a length of 170 km and assume the role of the city's primary transportation backbone. Remarkably, this advanced system will facilitate swift travel across the entire cityscape, reducing travel time to mere minutes. Engineered to achieve speeds of up to 300 km per hour, the SPINE will stand as a testament to exceptional engineering prowess. Its emphasis on velocity will obviate the necessity for private vehicles, thereby fostering a sustainable urban environment devoid of car dependency. Beyond its transportation function, the SPINE will epitomize Neom's steadfast dedication to sustainability. By employing clean energy sources, the rail system will prioritize efficiency and endeavor to minimize environmental impact. Neom's visionary aspiration will be to revolutionize urban transportation through the implementation of the SPINE, thereby establishing a novel benchmark for sustainable cities [5]. In summary, our manuscript provides the following core contributions:  
* Developing the dual transceiver FSO communication system considering both LN and GG channel models, aiming to precisely depict path loss attenuation, pointing misalignment, and the varying intensities of turbulence (weak, moderate, and strong) within the specific conditions of the Neom smart city. * Extending the scope of our research involves the inclusion of the siding loop scenario in the single-line track (a siding loop refers to a section of a railway track that branches off from the main line and forms a loop or parallel track; it is designed to allow trains traveling in opposite directions to pass each other without disrupting the main flow of traffic), introducing a unique element that enhances the system's practicality and yields valuable insights into its real-world performance. Notably, to the best of our knowledge, this specific aspect has not been considered in any other existing systems. * Analyzing and computing the received SNR in relation to coverage distance, along with the BER for both channels, offers valuable insights into the system's performance. This is achieved through the use of analytical expressions and validated results obtained via Monte Carlo simulations. * Carrying out a comparative analysis with both RIS-assisted FSO and relay-assisted FSO systems, showcasing that our proposed model demonstrates superior performance in coverage area and required infrastructure. The subsequent sections of the paper are structured in the following manner: Section 2 presents a comprehensive review of the relevant literatures and research. Section 3 of the paper introduces the description of the dual transceiver model, as well as the siding loop scenario and the handover procedure. Section 4 presents channel modeling using LN and GG models, considering the atmospheric turbulence of the Neom smart city. In Section 5 performance analysis is conducted for different channel models. Numerical results are explained in Section 6. Furthermore, a comparative analysis is conducted, comparing the results with the aforementioned existing FSO systems, and emphasizing the achieved improvements. In conclusion, Section 7 provides a concise summary of the key findings and contributions of the research.