Ricerc@Sapienza

Free-space line-of-sight (LOS) near-infrared (NIR) optics is a quite established field of research and application. Tropopsheric molecular and particle scattering at ultraviolet (UV) wavelengths can enable non-line-of-sight (NLOS) communication which brings robustness to blockage or shadowing. NLOS communication is particularly desirable to relax or eliminate pointing, acquisition and tracking requirements. NLOS-UV links can be used as an alternative to outdoor LOS-NIR links or in combination with existing optical or radiofrequency wireless links.
Analytical, experimental and numerical approaches have been used to determine the LOS-NIR and NLOS-UV channel impulse response and path loss. These studies demonstrate that UV channel is of multipath nature due to the volumetric scattering due to air molecules, aerosols and hydrometeors. Channel performances may be also degraded by high path losses and turbulence-induced fading as the link range increases. The proposed UVScat project aims at evaluating the potential of tropospheric NLOS-UV technology, focusing on channel modeling and system performance. The goal is to model the optical channel physical layer into account the complex interaction between transmitted UV radiation and tropospheric constituents such as gas molecules, aerosols and hydrometeors.
The tasks are the following: i) modeling atmospheric particulate scattering and turbulence at UV wavelengths; ii) development of an analytical wave-based model at UV wavelengths; iii) development of a Monte Carlo photon-based model at UV wavelengths; iv) simulation of UV communication channels and ozone scatterometer observations. The output of the UVScat project is supposed to be a feasibility analysis of the NLOS-UV technology (when compared to LOS-NIR links) and its potential for both telecommunciations and remote sensing as a basic step for a system and experimental future activity devoted to the verification of the proposed NLOS configurations.