The invention relates to a data transmission in a digital mobile communication system. In a mobile communication system employing a so-called multi-channel access technique, one or more traffic channels may be allocated to a mobile station (MS) for data transfer, in accordance with the data transfer rate required by the application using the mobile station. In the invention, a data call is determined minimum and maximum requirements for the data transfer rate of the user data. The mobile communication network (BSS, MSC) dynamically adjusts (Handover CMD/Additional Assignment) the channel configuration assigned to the mobile station (MS) for the data call and consisting of one or more traffic channels, within the limits of said minimum and maximum requirements of the data channel, depending on the changing allocation state of the resources of the mobile communication network.