A Design Of Video Stream Transforming System With Light Path Based On FPGA

For the past few years, wireless communications have obtained rapid development, bringing great influence of people’s life. For exam ple, the popular 3G technology in mobile communications, the spreading 4th-Generation and the Wi Fi technology usually used in Wireless-LAN, have brought grea t convenience for modern people’s life and working-style. With the progress of th e White-LED Lighting technology, how to translate wireless information using LED li ght has attracted m any people’s attention. Based on that idea, this paper described an experimental program that translates network video stream with LED lig ht, and illustrated how to m ake it come true with hardwire circuit.The innovation point of this research is that combining the advantages of LED lighting and wireless communica tions, the Ethernet data st ream could be transforme d with LED light. In th is case, the p roblem that the bandwidth is lim ited and ener gy consumption is too heavy could be solved. Al so, it has great advantages such as ener gy conservation and environmental protection.This system could trans late Ethernet vi deo stream with fl ashing LED light, the principle of which is that transform the Ethernet-Style video stream information to serial signals, which control the on and of f of the LE D light firstly, then recover the serial signals with a photoelectric conversion module, after which transform the serial signals to GMII format Ethernet data to receive and broadcast for the back module at last. The implementation of this research is as follows:The software——VLC installed on transmitting PC sends video strea m to cable through network card, then th e PHY chip on transmitter board will receive the d ata stream and trans late it to GMII form at for FPGA on board. FPGA could act as data cache, parse the message, switch the channels and fulfill parallel-serial conversion. The serial signals carrying Ethernet data drive LED circuits to generate light path blinking at high frequency, then the photoelectric conversion circuit will transform the light signals to serial electrical signal for latter circuits. The receiver board mainly contains FPGA and PHY chip, on which FPGA could recover data from the serial signal and send the m to PHY, which converse the GMII-form at data to signal in RJ-45 pattern. In that case, the receiver PC could communicate with receiver board through network cableconveniently. In the end, th e VLC installed on receiver PC will receive the video stream and play it for audience.This system is tested after finishing de bugging, the results have showed that they have met all the requirem ents from the cu stomer. These requirem ents includes: the bandwidth of the ligh t path is 20 Mbit, video stream could be switched by UAR T commands or UDP port number, the delay of the synchronous video stream is less than 0.5 s, during the playing of the synchronous video stream which is 720 P, the Frame Lose Rate is 0.The joint debug of this system is completed successfully as yet, but much m ore improvement is still needed to meet the market demand. Meanwhile, this program could also provide reference design for other LED light communication engineer.