Non-Line-of-Sight Ultraviolet Communication With Receiver Diversity in Atmospheric Turbulence

In this letter, we propose spatial diversity reception of non-line-of-sight (NLOS) ultraviolet (UV) communication in turbulent atmospheric channel. The turbulent atmospheric channel causes fluctuation in the received signal intensity of a UV system, resulting in power loss and subsequent performance degradation at the receiver. To mitigate this adverse effect, we present the spatial diversity reception in the form of dual-branch switch and stay combining (SSC) at the receiver. That is, one branch is only connected to the receiver at any instant using appropriate switching logic. The channels are assumed to be exponentially correlated in space, while irradiance fluctuation due to turbulence is modeled by a Gamma-Gamma distribution with parameters directly related to the attributes of the NLOS UV link. Analytic expressions for both the outage probability and the average symbol error probability are derived using the SSC diversity technique with the correlated receivers.

I. Introduction

The ultraviolet (UV) link can potentially offer low-power transmission, abundant unlicensed bandwidth, and high security. An efficient non-line-of-sight (NLOS) communication can be established using UV wavelength because of unique scattering by atmospheric channel constituents [1].