| With the rapid development of solid-state lighting technology,many new application technologies have been derived around the characteristics of its light-emitting diode(LED).Visible Light Communication(VLC)uses the strobe characteristics of the LED itself to modulate the signal through LED devices.The high-speed optical carrier signal that cannot be detected by the human eye is transmitted in the space freely.The received signal is demodulated by the photodetector.Regeneration to achieve the transfer of information.Visible light communication technology has the characteristics of green and healthy,no radiation without spectrum certification,good information security and convenient system construction,and is in line with the national sustainable development strategy.At present,VLC research units around the world,the study focused on a single LED devices and below 1W,does not meet the lighting requirements.The author thinks: VLC will have a way out only if it meets the lighting requirements.In this paper,the visible light communication and lighting technology are studied,and a modular visible light communication system based on LED lighting is designed and implemented.The system frame structure includes the uplink and the downlink,the downlink system light source is a watt-level phosphor white LED,and the uplink light source is an infrared laser diode(LD).As far as possible,the visible light communication technology is implemented Reduce the harm of the light source to the human eye and interfere with the downlink,and realize the real-time upload and download of the Internet data through the uplink and downlink at the same time.In order to facilitate the industrialization,the VLC system comes with mature technical solutions and components.For example,the system adopts on-off keying(OOK)modulation mode;the emitting light source commonly used watt-class phosphor white LED devices,Aiming at the problem of insufficient modulation bandwidth of the white LED,a pre-emphasis circuit is designed.The receiving end adopts the PIN photodiode with high sensitivity,large effective area and low cost as the photodetector,and amplifies the small signal by using the transimpedance preamplifier with small dynamic range,low noise and high bandwidth,and combines with the transmitter pre-emphasis circuit in the receiver design after equalization circuit further the system bandwidth from 3MHZ to 133 MHZ.The communication unit modular design,make it small,standardized,simple and flexible only with the existing lighting fixtures for embedded installation.In this paper,a panel lamp with VLC function is designed.The integration of the main lamp with the communication main lamp makes the ordinary LED lamp possess the function of visible light communication and can meet the professional requirements of indoor lighting at the same time.Finally,the lighting and communication VLC system platform is set up to test the lighting function and communication function of the system,including VLC lamp test,transceiver module test,bit error rate test and Ethernet performance test.The test results are analyzed and evaluated in detail,and then relevant results are given. |
