Design of a high-speed data transmission link using free-space optics communication technology for metropolitan information networks

This paper describes the design and simulation of a high-speed data transmission link based on free-space optical communication (FSO) technology, motivated by the need for quick, cost-effective and high bandwidth solutions for metropolitan information networks. The proposed design helps to deal with unique characteristics of metropolitan information networks which are high node density with challenging physical infrastructures, high bandwidth connectivity demands at short to medium transmission distances, high atmospheric turbulence due to air pollution, smog, and building motion caused by transportation and construction activities. In the paper, key system parameters including receiver aperture diameter, transmitter beam divergence, electrical filter cut-off frequency, transmitted power and various environmental conditions are considered simultaneously to provide a design solution with a higher adaptability to channel instability due to high atmospheric turbulence and infrastructure constraints of urban area. The Q-factor is used as a quality criterion to evaluate through out the simulation and analyze of the system performance. For the data rate as high as 20 Gb/s of this study, the proposed FSO system design is ideal for scenarios that require short to medium-range high-speed links (up to 4 km) and under moderate weather conditions (visibility ≥ 2 km).