earticle

영어

In this paper, we proposed a new dimming control scheme by using direct sequence spreading coding (DSSC) scheme in visible light communication (VLC). VLC systems using LED lighting can provide illumination functions and communication services at the same time. In order to provide simultaneous illumination and communication services, dimming control should be considered. Dimming control means that LED lighting should maintain a constant brightness in accordance with user requirements while communication services are offered. In IEEE 802.15.7 VLC standard, on-off keying (OOK) and variable pulse position modulation (VPPM) are defined as pulse modulation schemes for dimming control. In particular, 4B/6B, 8B/10B block coding and Manchester coding schemes have been proposed for stable dimming control in OOK. However, in such a case, stable dimming control is possible although the communication performance is degraded. In order to solve those problems, we propose a VLC system based on OOK modulation with DSSC. The proposed system can simultaneously stabilize dimming control and improve communication performance by obtaining spread diversity gain. The simulation results show that the proposed system provides superior dimming and BER performances compared to conventional dimming modulation schemes.