The Research On Construction Of SFN In Railway Television System

The railway is not only the major part of the national transport in china,but also the chief method the civilian choose to travel.However,in order to provide comfortable environment and public information service,different kind of TV set,telephone,computer systems had been fixed in airplane and ship.When refer to the railway,that has the length of 70,000km and the passenger transport of 1,600,000,000 person-time per year,it's still a blank of the television broadcast coverage.Confronted with the competition from the airway,waterway and highwaytransportation ,the railway should solve the problem that passenger train especially the long-distance train has no TV set on it. The research on digital video broadcasting has been carried out in abroad for several years. In our country, standard for digital television terrestrial broadcasting system had been published in August,2006. In this standard, both OFDM(C=3780) and signal carrier(C=1) are exist. Similar with OFDM system, DTTB standard for China can be used in very complex terrain. It also can be used in high speed vehicle, like the signal carrier system. DTTB standard for China is the most promising solution for Chinese railway TV.DTTB standard(C=1) has strongpoints such as better C/N performance, low minimum requirement input levels, low transmitter power,immunity to analogue and digital signal.In order to solve the problems in Chinese railway TV, we improve the DTTB standard and get a upgraded one- ADTB-R. ADTB-R can be used in high speed railway, insure the reception quality in train .Based on the ADTB-T system developed by Shanghai Jiao Tong University,the railway television SFN system takes DVB-S as primary distribution network,which also be composed of Optical fiber and microwave at some certain area.With the national wide railway coverage,the system can provide live TV program from CCTV with the receiver fixed in the train.The reliable design insures the synchronization of the railway TV signal broadcast and the continuity of the TV program.