Train radio system using leaky coaxial cable

The Japanese National Railways has stretched its bullet train system to the north in 1982 and built a new type train radio system for it. The new system utilizes Leaky Coaxial Cable, a wired-wireless technique which offers many services such as train operation dispatching, passenger dispatching, public telephone, train status monitoring and so on. Taking advantage of sufficient receiving level from LCX, the system was designed to have 40 dB signal to noise ratio at more than 99 percent areas for voice communication channels and less than 10^-4bit error rate at almost all areas for 1200 bit/s FSK data communication channel. Measurement after construction of the railway lines has verified that the intended quality is attained for both voice and data communication. Block error rate for triple transmission of same data also proved to be less than 10^-3in the measurement. In this system, stable receiving level for relatively small power and efficient use of frequency resources are realized through isolat ion between zones and narrow dynamic range of LCX.