Research On Networking Technology And Security Technology In Visible Local Area Network System

Visible light communication is a rapidly developing information transmission technology in recent years.It transmits data through visible light and can be combined with daily lighting systems to make the visible light communication system have both communication and illumination functions.At the same time,visible light communication technology has attracted wide attention from domestic and foreign research institutions due to its advantages of high-frequency bandwidth,high speed,low power consumption,good safety,and no electromagnetic interference.With the deepening of research,the research on modulation technology,equalization technology,and MIMO technology in visible light communication tends to be mature,and the system communication rate is also increasing,but there are relatively few studies on the Ethernet access scheme,corresponding networking mode and LAN security of the visible light local area network.The combination of visible light local area network and Ethernet not only expands the application scenario of visible light communication but also provides a safer and high-speed local area network access solution,and authorized access and data encryption ensure the communication security of the wireless network.In this thesis,the system architecture,multi-access control protocol,access authentication protocol,and data encryption and decryption algorithm of visible light local area networks are designed and implemented respectively on FPGA,and the system performance indicators of local area network are tested.The research content of this thesis mainly includes:1.According to the transmission characteristics of LED visible light,in this thesis,we proposed a construction scheme of visible light local area network communication system,including topology structure,selection of uplink and downlink transmission medium and hardware platform construction.2.Based on CSMA/CA protocol,in this thesis,we designed and implemented the multi-access control protocol of visible light local area network in FPGA according to the situation of multi-terminal access LAN,including virtual carrier monitoring mode design,control frame conflict resolution,control frame format design,and data priority relationships between transmission and reception.3.Based on WPA protocol,we designed and implemented LAN access authentication protocol and data encryption protocol according to the data transmission characteristics of visible LAN,including the design of the access handshake process,the design of the relevant frame format,the key generation algorithm,and the implementation of the data encryption and decryption algorithm.4.In this thesis,we verified the LAN networking function and security function from FPGA simulation,chipscope data acquisition,serial data transmission and access to the Internet.Experiments show that visible light LAN can transmit the network at high speed and safety.Besides,we quantitatively test the performance indicators of visible light LAN systems,including broadband access speed,system throughput,packet loss rate,system delay,and coverage.