Optimization Of Visible Light Communication System Performance And Realization And Research Of New Mode

In recent years, more and more scholars and experts in communication field have been involved in the research and implementation of visible light communication (VLC) system. Among them, especially in LED-based visible light communication system.Visible light communication technology is based on visible light as an information carrier, without optical fiber and other cable channel transmission, in the free space directly transmit optical signal communication. In addition, compared with radio frequency communication and radio communication, the advantage of the visible light communication is green, harmless to the human body and spectrum resources without certification and application. Therefore, the visible light communication is also regarded as complementary technology with the communication technologies such as WiFi, cellular network (3G, 4G,5G), etc., and plays an important role in the Internet of Things, Intelligent City, transportation and other fields.At present, the research of visible light communication has already made some achievements. In the design of visible light communication system, many domestic and foreign scholars have put forward a large number of off-line program designs and realizations, that means, using PC computer for signal modulation, optimization and demodulation processing. But there are few research results on the design scheme of visible light communication system. Therefore, how to realize visible light communication online system has become hot and difficult in recent years. In addition, the visible light communication system is unidirectional communication system, which also makes it lose its original advantage in the practical communication application. The solution of these problems is of great significance to the application and development of visible light communication technology.Based on the National Natural Science Foundation of China, this paper focuses on the realization and performance of visible-light communication online system, and proposes the design and implementation of real-time visible half-duplex communication on-line system for the absence of optical communication link, the main work is as follows:First, the present situation of VLC technology is summarized, and the basic principle and im,plementation method of real-time VLC system using light-emitting diode (LED) are expounded.Second, the performance of real-time VLC system is analyzed and analyzed. For the problem of low system rate and high bit error rate, a scheme is proposed to improve performance through A/D conversion circuit. The accuracy of the signal decision is improved and the bit error rate of the system is reduced.Thirdly, a real-time VLC system with LED instead of photodetector is proposed, and the corresponding half-duplex communication mechanism is proposed, and the experimental test and analysis are carried out. The results show that the maximum downlink rate is 2.6Mbit / s and the maximum uplink communication link rate is 2.55Mbit /s.