The air interface facilitates the communication (voice and data) between mobile stations
such as hand-held mobile radios, data radios (Remote Terminal Unit, RTU) and radio
dispatcher workstations. The radio channels for this purpose are generated via transceivers of the base stations that are available in various frequency ranges. The traffic
and packet data channels are dynamically occupied. Signalling and short messages
(SDS) are transmitted via statically configured control channels (MCCH and, if necessary, SCCH).