Bidirectional Hybrid Optical Wireless Communication System for Indoor Networks

A B S T R A C T Optical band of electromagnetic spectrum is classified into three portions i.e., infrared, visible and ultraviolet lights. Using visible light for downlink transmission is strongly appreciated because it provides communication along with illumination. But for uplink, visible light is avoided as it is uncomfortable for eyes and due to energy limitation of portable devices. Instead of visible light, infrared light is more attractive for uplink if used according to eye and skin safety standards. This paper takes into consideration a bidirectional hybrid OWC system for indoor networks which consists of VLC for downlink and IRWC for uplink. For both transmitters (LED send IRED), transconductance circuits with feedback topology are used. On receiving side, same op-amp based circuit with PD BPW34 is used for both VLC and IRWC. The commercially available USB to TTL converters is employed on both sides as processing units. The experimental setup is used to examine the SER with respect to separation between transmitter and receiver for different BR. According to results, The SER increases, and CRS decreases with increasing separation at same BR or with increasing BR at same separation. the best SER vs distance range were obtained at BR 1200 and below 1200 for VLC and IRWC.