Design And Implementation Of Real-time Radio And Video Visible Light Communication System Based On USB Interface

With the development of solid state lighting devices, white light LED has been widelyconsidered as the green lighting products for the next generation and is gradually becoming theleader in the lighting market. Based on its characteristic of high speed frequency response, whitelight LED has expanded its function to the communication field and is able to play its part in thesystem integrated with lighting and communication functions which is widely applied in manyspecific indoor or outdoor circumstances.The paper first introduces the advantages, characteristics and international development ofVisible Light Communication (VLC). Next, characteristics of the key component of VLC systemwhite light LED, its working theory and several basic link modes of VLC are illustrated.Accordingly, the paper focuses on the detailed analysis of LOS channel model which is commonlyapplied in short-range wireless communication scenario. An LOS model is conducted andMATLAB software is adopted to simulate the optical received power, SNR (Signal to Noise Ratio)and BER (Bit Error Rate). Also, the path loss and received optical power is calculated which lays atheoretical foundation for VLC system construction.Besides, the VLC tranceivers based on USB interface and corresponding supporting softwareare designed separately. The system composition, circuits of transceivers and components selectionis discussed in detail. And the software is realized based on serial ports technology and DirectShowAPI using C#programming language. The M-JPEG compression method is adopted to ensure thesmooth and stable transmission of video signal while avoiding the influence of limited transmissiondata rate of hardware interface. Combining hardware and software, characters can be transmittedwith the distance of2m and real-time radio and video transmission within30cm is realized.