Research On Visible Light Parallel Communication System's Scheme And Key Technology

Visible Light Communication(VLC) is an emerging optical wireless communication technology which is developed with white LEDs. VLC uses the high speed response characteristic of LEDs and modulates the information in visible light waves of LEDs. This dual function of LED, for lighting and communication, creates an absolutely new method of broadband access for optical wireless communication.In high-speed VLC transmission, the inter-symbol interference caused by multipath effects limits the maximum data transfer rate. We studied the VLC-OFDM(Or:hogonal Frequency Division Multiplexing) modulation method which has high bandwidth ratio and good anti-jamming ability. The modulated bandwidth of current application white LED is low. In order to realize the extensive application of large-capacity VLC, we combined two-dimensional code with VLC, and proposed a parallel communication system's scheme which can improve the communication capacity of VLC. It is a new method to high speed VLC technology.The main contents include:The OFDM modulation method was used in VLC system. We mainly studied the transmission property of VLC-OFDM system in multipath fading channels-We combined the two-dimensional(2D) code with VLC, proposing a parallel communication system's scheme to improve the communication capacity of VLC. The system included both static and dynamic program. The visible light static parallel communication system used LED as the background light source, and used of micro 2D code to transmit information. This system used the principle of microscope. The transmitted 2D code could be captured from a long distance. An amplified 2D code image was received, and could be accurately decoded. The visible light dynamic parallel communication system used LED arrays to make up dynamic QR code to transmit information. We focused on the LED array QR code's positioning technology, and the image processing technology after the image was located. Finally, a standard QR code was obtained, and this code could be accurately decoded.