The Research Of Video Collection And Transmision System About Rail Road Emergency Communication

The railway has been carried out in protection of China's economic construction of high-speed artery. It has played an irreplaceable important role in Chinese economic development.Railway transport of bulk cargo are in the commitment.Such as passenger, freight, coal, grain, civilian, military and more.Now, with the national railway 6th great speed and high speed of 300 Kn above the opening line of EMU marks the rail transport equipment, technology has produced a qualitative leap. Meanwhile, emergency communication system is also proposed new requirements because of the rapid development of the railway, namely:in a shorter period of time to deal with accidents and restore operation. Therefore, the development and construction of the command and emergency video wireless transmission system is imminent. It can made the command center to obtain the function that can look directly at, direct control of the railway scene of the incident. This paper analyzes the post-modern railway network and come to a conclusion that it is feasible to use the H.264 video compression standard which used for wireless video communication system.This paper analyzes the electromagnetic environment of railway and the characteristics of channel fading of OFDM in which the electromagnetic environment. and on the basis of the characteristics of OFDM channel fading to analyze the impact on video data. According to above analysis. this paper puts forward a anti-interference strategy that combine h.264 anti-interference measures with OFDM.According to this strategy. design a new interleaver method.This mixed approach include:the video data slice serial/parallel conversion and shaping. receiver and statistical of the channel estimation information. interleaving and synchronization decision means, the out-of-band channel communication protocols for video sequence parameter set. image information and channel estimation information.Using Matlab/Simulink simulation software to establish OFDM simulation model of the railway electromagnetic interference characteristics. and on this basis. design a new mixed mode of function modules. including video data slice series transformation and shaping module, received and Statistics function module of channel estimation information. interleaving pattern decision and synchronization module. out-band channel communication protocol modules for video sequence parameter set. image information and channel estimation information. these modules form a new strategy based interleaver. The new interleaver with a simulation model of OFDM compare with OFDM with general interleaver simulation model in the different simulation electromagnetic environment.Simulation results show that under different S/N and the Doppler effect, the new interleaver with a simulation model of OFDM get the smaller BER value and the higher PSNR value.Prove that the new interleaver with a simulation model of OFDM transmission with the video quality is superior to the general simulation model of OFDM interleaver. Verifies the strategy is effective and feasible.Finally. this paper analyse and summarize the test data and come up with an improvement methods and an improvement in the future direction.Hope that the practical application in the future have better results.