Patent ID: RE39375

Claim:
A method for transmitting packet data in the air interface of a digital cellular system based on time division multiple access (TDMA), the system comprising a communications network having at least one base station which serves a cell with wireless bidirectional communications using uplink and downlink time slots a plurality of which comprise an uplink and a downlink TDMA frame, respectively, the system further having at least one mobile station located within the cell, comprising the steps of: defining downlink logical channels from the base station to the cell, the downlink logical channels being defined to comprise information channels designated for information transmission, the downlink logical channels using the downlink time slots, defining downlink control channels which include at least one of a paging channel (FP) and an acknowledgement channel (A), of which on the paging channel the base station notifies a mobile station located within the cell of an incoming packet data transmission that is addressed to the mobile station, as well as information channels for transmitting the incoming packet data, the downlink control channels also using the downlink time slots, defining uplink logical channels from the mobile station to the base station, the uplink logical channels being defined to comprise information channels reserved for information transmission and a reservation request channel (R), the uplink logical channels using the uplink time slots, making a request to the base station from the mobile station on the reservation request channel to reserve a connection for transmitting packet data, and acknowledging the request by the base station on the acknowledgement channel by identifying those information channels on which the mobile station is to transmit packet data, wherein in the TDMA frames there is assigned at any given time a variable number of time slots designated for packet data transmission, the number of assigned time slots being a function of one of a symmetricity and an asymmetricity of the packet data transmission, and also on a total demand for packet data transmission in the cell, and wherein any of the downlink time slots in the TDMA frame assigned for packet data transmission can be used for the paging (FP) channel and the acknowledgement (A) channel, and any of the uplink time slots in the TDMA frame that are assigned for packet data transmission can be used for the reservation request (R) channel.