Transmission system and coding communication method for a transmission system

A transmission system far use along a predetermined route comprising:

• a plurality of modules installed at different positions along the predetermined route, each of the plurality of modules including:
• i) receiving means of receiving an input signal having a radio carrier frequency containing information, and
• ii) transmission means of transmitting an output signal based on said input signal;
• said output signal of a respective module including a first transmission signal which is transmitted to a first adjacent module on one side of the respective module, and a second transmission signal which is transmitted to a second adjacent module on another side of the respective module,
• the first and second transmission signals of the respective module both having the same radio carrier frequency, and both having a radio carrier frequency different from a radio carrier frequency of said input signal, thereby to reduce interference among the plurality of modules;
• and
• said output signal from each of the plurality of modules including at least a portion of the information contained in said input signal, and said output signal transmitted along at least a portion of said predetermined route;
• wherein the respective module is at a single location along the predetermined route and receives from/transmits to a mobile unit from the single location, and
• the mobile unit communicates with only one respective module at one time.