Research On Visible Light Communication Technology Based On Three Primary Color White LEDs

With the popularization of the mobile devices,mobile communication faces the challenges of shortage of band-resources.New technologies with free band resources and high communication rate are required to solve the problems.As a new wireless communication technology,VLC(visible light communicationVLC)based on LED(light emitting diode-LED)has many advantages,such as abundant bandwidth resources,lighting function and no electromagnetic pollution.As a supplement of traditional communication technology,it has great potential for development.In order to improve the communication rate and link stability of visible light communication and to promote the practicability of visible light communication,the visible light communication link based on three primary color white light LED and avalanche photodetector is studied in this dissertation,and the WDM(wavelength division multiplexing-WDM)experiment is carried out,and the visible light access Ethernet is realized on the communication link.In order to improve the modulation rate of the transmitter,the three primary color white light LED is used instead of the traditional phosphorescent LED in the communication link,and so with the carrier discharge circuit.The avalanche diode is used as the photoelectric converter of the receiver,and the automatic gain control circuit is introduced into the signal processing module to improve the reliability of the system.In order to make full use of the communication potential of the three primary color white light LED,the WDM technology is introduced to visible light communication by this dissertation,and the rate of visible light communication is increased by driving the three color luminescent chips of red,green and blue respectively.Finally,based on the above,the access method of visible light communication network is studied in this dissertation.The visible light Ethernet communication terminal is designed and produced,and the Ethernet-visible light communication protocol conversion module and visible light communication coding/decoding module are written.The experimental link of visible light communication Ethernet access is built,and the access effect is tested by desktop computer.Experiments show that the link realizes the purpose that user can access to the Ethernet and browse the Internet through visible light communication.