A wireless network includes a radio network controller and a plurality of terminals which are provided for transmitting useful data over logic channels which have different priorities, which are mapped onto exactly one transport channel, respectively. The data transmission over a plurality of combined (multiplexed) transport channels is determined by transport format combinations. The respective most favorable transport format combination is selected at the beginning of a radio frame, given the packet data units waiting in the buffers of the logic channels. Further, the logic channels are sorted while their priorities, their buffer occupancy and the transmission time interval of the associated transport channel are taken into account.