The Design Of Wireless Image Transmission System Based On COFDM

With the development of communication technology, wireless video transmission technology has been widely used in industry and in all areas of social life. The rescue and monitoring in the field of Public safety require the transmission of the video, the voice and data in real-time and synchronously. However,there are limited resources and much interfernce in wireless channnels,and heavy traffic and high real-time demand for video signals.Aiming at these problems,this thesis analyzes how COFDM technelogy is used to implement wireless video transmission under the condition of high moving speed.After briefly intruducing COFDM technelogy theories,its major advantages and shortcomings,this thesis focuses on the whole design of COFDM-baced clear video transmission system. The COFDM system is the union of channel coding and the OFDM technology.The article introduced the channel coding and discussed how the system to resist each kind of decline through the channel coding.The system uses the structurization design. According to the system whole request and the target assignmen,the system is divided in to many modules, including the code module, the data multiplying module, the COFDM modulation module, the filter unit, the low noise amplifier unit and so on.The article described various modules unit function and gave each unit electric circuit's design.After a series of hardware tests and environmental testing, the system further verifies the rationality and feasibility of the design. Test results show that the system basically meets the design requirements, the image can transport at the speed of 150km/h reliablely in a typical urban environment. Currently, the system has been widely used in command, rescue and other public safety fields.