Differential-OOK System for Underwater Visible-Light Communications

Abstract

Underwater wireless optical communication (UWOC) can provide higher data rate communication over middle-distance for new underwater applications. However, high-speed data transmission inUWOCis mainly limited bywater spectral at- tenuation characteristic and background-noise. In this study, we propose an analytical underwater daylight noise model which incorporates a daylight simulation model SPCTRAL2 with an upwelling solar radiance model for the practical anal- ysis with background light for UWOC. Moreover, we also consider a differential on-off keying (DOOK) system in our simulation model. This DOOK system was proposed to re- duce the influence of back-ground noise for the free-space op- tical communications. Consequently, the bit error rate (BER) performances of DOOK system are better than those of OOK system with fixed threshold because the DOOK system re- duces the effects from sunlight. For example, when water property is coastal, theDOOKsystem can improve about 7dB compared with an OOK system with fixed threshold. In ad- dition, the DOOK system can achieve the BER performance less than 10−6 in coastal property all day.