Patent ID: 7171196

Claim:
A cellular system for trains for transmitting and receiving information by radio, the system comprising: a wayside subsystem comprising a plurality of stationary transceiver stations distributed along a determined path and allocated to successive cells, the transceiver stations of a given cell being spatially separated from each other and comprising at least two transceivers directed toward each other; a plurality of trains constrained to travel along the determined path, each of the trains carrying a transceiver, and a controller controlling the transceivers of the stationary stations and the transceiver carried by each train such that, while a train of said plurality of trains is in a given cell, exchanges between the transceiver of the train and the transceivers allocated to the given cell take place on two different frequencies in alternation during two successive radio cycles so that for a radio communication between the transceiver of the train and the transceivers allocated to the given cell lasting a plurality of radio cycles in sequence, the communication takes place at a first frequency during a first radio cycle, at a second different frequency during the next radio cycle in the sequence, at the first frequency during the following radio cycle in the sequence after said next radio cycle, at the second frequency during the ensuing radio cycle in the sequence after said following radio cycle and so on, depending on the number of radio cycles, in a repeating pattern alternating between said first and second frequencies so as to provide increased immunity to interference during the radio communication between the transceiver of the train and the transceivers of the given cell.