Performance Analysis of Cooperative NLOS UVC System with Receiver Diversity

Ultraviolet (UV) communication with its ability to operate non-line-of-sight (NLOS) mode offers several advantages as compared to the conventional optical wireless communication systems (OWC). NLOS UV communication (UVC) relaxes the pointing, acquisition and tracking (PAT) requirement; and also experiences extremely less background noise at earth surface due to the absorption of solar radiation by the ozone layer. Due to very small wavelength, UV signal strongly interacts with atmospheric particles and aerosols, thereby resulting in strong scattering and NLOS connectivity. The NLOS UVC, however, suffers with very high path loss and turbulence induced fading whose effects become more severe for large communication distance. In this work, we address these challenges by introducing a NLOS UVC system which incorporates relay to extend the communication distance and multiple receiver branches at the destination to mitigate the effect of fading. Performance analysis of the considered system model leads to deriving novel closed-form expressions for the outage probability and average symbol error rate. We evaluate the system performance for different configuration parameters and modulation formats. Correctness of the derived analytical expressions is validated through Monte-Carlo simulations.