A data transmission in a digital mobile communication system employing a so-called multi-channel access technique, in which one or more traffic channels may be allocated to a mobile station for data transmission in accordance with the data transfer rate required by the application using the mobile station. Upon establishing a data call, the mobile station indicates to the mobile communication network the maximum and optionally the minimum requirements for the user data transfer rate. The mobile communication network assigns the mobile station for a data call a channel configuration consisting of one or more traffic channels in connection with call set-up or handover, the channel configuration depending on the resources currently available in the mobile communication network and enabling performance of the data channel, which is not lower than the minimum requirement and not higher than the maximum requirement.