Half‐duplex visible light communication using an LED as both a transmitter and a receiver

In typical visible light communication (VLC) systems, light‐emitting diodes (LEDs) are used as optical transmitters and photodiodes are used as optical receivers. Currently, many communication devices such as smart phones have a built‐in LED lamp whereas they usually do not have a built‐in photodiode. If we find a way to receive VLC signals without the need to add an additional photodiode on the communication devices, it will contribute to the spread of VLC. Therefore, we propose and demonstrate a VLC scheme without the need for a photodiode. As the first step, we investigate the characteristics of an LED as a VLC receiver and find out that an LED can also be used as a VLC receiver in certain conditions. Then, we demonstrate a half‐duplex VLC system using an LED as both an optical transmitter and an optical receiver, without the need for a photodiode. This technique could be used in various applications such as the VLC between smart phones with a built‐in LED lamp and the VLC between LED traffic lights. Copyright © 2015 John Wiley & Sons, Ltd.