Amplify-and-forward based cascaded RF-UWOC system

Abstract

A cascaded radio frequency-underwater wireless optical communication (RF-UWOC) system using an amplify-and-forward relay is considered. UWOC supports high speed communication for underwater surveillance, monitoring of climate change, and different deep-sea mining activities making it a s suitable substitute to underwater acoustic communication. The proposed fixed-gain AF based cascaded radio-optical system can connect underwater with land. The system comprises of Nakagami-m faded radio link and mixture Exponential-Generalized Gamma (EGG) faded UWOC link. Salinity, air bubbles, and thermal fluctuations in water causes underwater optical turbulence (UOT). Optical signals are modulated by subcarrier intensity modulation technique at the relay and heterodyne or direct detection is performed at destination. For this proposed communication system, outage and error analyses are carried out. It is observed that the performance of the considered system deteriorates more because of the underwater optical turbulence (UOT) due to thermal fluctuations and air bubbles as compared to UOT introduced by salinity.