Design and optimization of a Free-Space Optical (FSO) communication system for reliable outdoor connectivity in hospital departments in Malta

<ns3:p> Background Modern healthcare facilities face the challenge of ensuring secure, high-speed, and interference-free communication across hospital campuses. In Maltese hospitals, electromagnetic interference (EMI) from RF systems and the high cost of fibre deployment are major limitations. Free-Space Optical (FSO) communication offers a promising solution by providing gigabit-per-second transmission without EMI-related disruptions. Methods This study proposes the design and optimization of a 1550 nm FSO communication system using OptiSystem 21 and MATLAB R2024b. The design incorporates Malta’s Mediterranean climate, dominated by haze with rare fog, into atmospheric attenuation models. System parameters, including attenuation coefficients, Q-factor, bit error rate (BER), and link availability, were evaluated under different weather conditions. Results The system maintains reliable performance when rain attenuation is below 3.5 dB/km, achieving a Q-factor above 6 and error-free transmission in clear air with BER &lt; 10 <ns3:sup>−12</ns3:sup> and a Q-factor of 13. The link operates optimally up to 2 km and sustains receiver sensitivity (–35 dBm) up to 5 km at 17 dBm transmit power. Simulations demonstrate high availability (&gt;99%) under clear, hazy, and rainy conditions, while fog—occurring less than two days per year in Malta—reduces availability but does not impact the overall system feasibility. Conclusions The proposed standalone FSO system eliminates EMI risks, lowers installation costs, and simplifies deployment compared to RF-based or hybrid designs. It provides a hospital-focused, cost-effective, and scalable framework that ensures secure and high-speed transfer of medical imaging, telemetry, and electronic health records. Tailored for Malta’s climate, the system represents a sustainable blueprint for next-generation hospital communication infrastructures, combining EMI safety, high availability, and environmental resilience. </ns3:p>