Research On Key Technologies Of Visible Light Communication Base Station System

Visible light communication(VLC)systems can transmit signals with LED instead of wireless local area network base stations.The communication rate of VLC can reach hundreds of megabits per second and is likely to exceed that of optical fiber communication in the future.VLC can be used in aircraft,hospitals,security agencies,smart grid and other electromagnetic sensitive places owing to excellent antielectromagnetism disturbance ability,large transmission bandwidth and low electromagnetic radiation.In recent years,most of the research on VLC focuses on the visible light channel and optical chips,but little attention has been paid to VLC base station system.This paper has proposed a VLC base station system with ACO-OFDM and photoelectric label system.Among them,the VLC base station system includes variable-rate high-efficiency ACO-OFDM digital modulation and demodulation system,optical transmitter and optical receiver.The photoelectric label system mainly includes photoelectric label with external EEPROM.The modulator and demodulator of VLC system is designed based on FPGA.The terminal tag,the optical transmitter and the receiver realize tape-out with UMC 180 nm CMOS standard.Firstly,the paper introduces the current situation and future development of VLC as well as analyzing the advantages and disadvantages of VLC technology and its application fields.Then,the key technologies of modulation in VLC are introduced.An improved FFT algorithm is introduced for ACO-OFDM,and an efficient FFT module is designed based on this algorithm.The digital design of the key modules in the VLC modulator and demodulator is explained in detail,and the advantages of the variablerate and high-efficiency system proposed in this paper are analyzed.In order to verify the practicability of the VLC base station,a photoelectric label with external EEPROM is designed as the test terminal.Finally,the test of each part and the whole system are carried out,and the results are analyzed.The test results show that the VLC base station system can modulate the tag commands at the transmitter,demodulate the tag commands at the receiver,and successfully read as well as write the tags.