Design And Implementation Of Wireless Transmission Quality Optimization Scheme For Metro PIS System

In the resent year,as the improvement of the local economy and the growth of the metropolitan area,the urban rail transit in China shows a great increasing.As raised in 12th Five-Year comprehensive transportation system planning,increasing the informatization and intelligence of transportation system are the main ideas to improve the quantity of the customer service offering from the system manager.Passenger Information System(PIS)plays an important role in providing the information of the service,transporting guidance,travelling,news,advertisement and multi-media service,furthermore,PIS could offer passengers important information in the emergency circumstance.There is a technique drawback in the PIS,which is the unstable wireless connection during the high speed moving to the ground-based receiver,causing delay of the information.The unsmooth playing of the audios and videos and delay of information will raise the influence of the quantity of the service and make the passengers unconformable which cause a high intention.The main reason is that the train-ground wireless communication affect by the environment heavily,which could cause the slow data downloading and unloading and even more data damaged.In this dissertation,we are focusing on the analysis of the technique of the network transportation and audio decoding,and design a compatibility wireless network system that is suitable for all kinds of the train-ground communication.Applying the to file points blockage and compensating data retransmission mechanism assisting with data buffer,loading balancing optimization mechanism,the unstable of the train-carry media player was solved and stabilized the train-ground communication.This technique now equipping to the subway project,can increase the video property by using the delay-live-playing with a short term streaming in the storage instead of the live-playing.With enough streaming time,the probability of data losing could be decrease to zero.The applying of this technique could make a great change to the emergency releasement,profit increasing,and travelling experience as well as solve the short-back in the subway industry.