Method for transmitting data in a time multiplex transmission

A method for transmitting data between at least one central office and a plurality of mobile radio stations via a relay station by a time multiplex transmission procedure in which signals are transmitted in a succession of time frames and the central office transmits on a first frequency to all mobile radio stations via the relay station, said method comprising:

• causing the central office to periodically transmit different messages at arbitrarily selected times, which messages include routine inquiry messages, directed to each mobile station in sequence during each time frame;
• causing each mobile station to respond to an inquiry message by transmitting a selected short message on a second frequency;
• causing a selected mobile station to transmit data to the central office by transmitting to the central office an announcement of the intent to transmit data during a first time frame, causing the central office to set aside reception capacity for the data in a time frame following the first time frame, and transmitting the data to the central office in the following time frame;
• and
• causing the duration of each time frame to vary, on the basis of data transmitted during at least one preceding time frame, between a minimum value determined by the time required to transmit a routine inquiry to each mobile station and a maximum value determined by the time required to transmit data of a predetermined length to each mobile station in succession and the time required to transmit data of a predetermined length from each mobile station in succession.