In a radio communication system, at least a first frequency band is subdivided into C radio resource units which are allocable for radio transmissions between radio stations and terminals. Each radio resource unit has at least two adjacent subcarriers, for allocation of at least a first resource unit for a data transmission between a terminal and a radio station. The radio station receives from the terminal a first short training symbol which has spectrally the same bandwidth as the first frequency band and includes at least Q frequency carriers, where Q is greater or equal to C, but smaller than the total number of subcarriers. The radio station estimates the radio channel for at least the first radio resource unit using the first short training symbol, and an allocation of the first radio resource unit to the terminal is broadcasted by the radio station.