18㎓ 대열차공간화상시스템의 지상구간에서 영상전송특성 시험

It is increased that need of broadband multimedia service to make useful environment for user and to support the operation of railway system. So study of integrated data transmission in a subway and railway is activated. The research deals with pass loss characteristics of 18㎓ microwave that is assigned frequency of integrated data transmission in a subway and railway. It is used sample integrated transmission system in subway and railway of KRRI(korea railroad research Institute) at the tunnel and road. Specification of test sample system is blow. It use OFDM modulation, Wireless frequency is 18㎓ and 19㎓, Maximum output power is 20㏈m, Receive sensitivity is -90㏈m. The pass loss exponent and standard variation of road and tunnel is analyzed.