Performance analysis of cooperative relaying technique for non-line-of-sight UV communication system in the presence of turbulence

Ultraviolet communication (UVC) with its ability to operate in non-line-of-sight (NLOS) offers significant advantages as compared to conventional optical wireless communication systems. NLOS UVC is a short-distance communication system due to high path loss and turbulence-induced fading. We propose an effective cooperative multirelay system to combat the effect of attenuation and fading in NLOS UVC, thereby making it suitable for long-distance communication. We investigate the performance of the proposed system in terms of outage probability by considering both variable-gain and fixed-gain amplified and forward relaying. Further, we consider higher-order modulation schemes to improve the data rate of the system and derive innovative closed-form expressions of the average symbol error rate and diversity order for the variable-gain relaying. We demonstrate performance gains of the considered multirelay system over nonrelayed links for different system parameters. We present numerical results to confirm the accuracy of the derived analytical expressions.