A method and arrangement in a mobile terminal such as a UE for selecting a transport format for an uplink transmission to a base station, wherein the selector selects a transport format from a set of transport formats which are generated based upon parameters of a radio connection established with the base station. Upon establishing a radio connection, the base station sends parameters to the UE describing a radio bearer configuration. The UE generates a set of transport formats based upon the radio bearer parameters. A classifier then classifies each of the transport formats in the set as either power-efficient or power-inefficient. When a grant is received from the base station, the UE derives a set of allowed transport formats. A transport format selector then selects a transport format that is both power-efficient and allowed.