Audio multicast by Visible Light Communication for location information for the visually impaired

Visible Light Communication (VLC) is a new technology that may become an alternative choice for wireless communication in the future. The technology may be used in many indoor applications. The specific presentation of VLC in this study is with the use of light emitting diodes (LEDs) as the medium for transmission. Digital information will be sent through the LEDs as light pulses, and then a receiver will be able to collect the light pulses as a code and translate it to a corresponding audio data. In this study, the visible light communication system uses modulation schemes, such as on-off keying, so that the digital HIGHs and LOWs are representations of the binary code to be transmitted. Acknowledgement lights incorporated in the receiver are also utilized to make multicasting possible, and to signal that transmission is successful.