System that allocates a carrier frequency to a radio link, for transmitting data bursts between a remote unit and a fixed unit, by employing orthogonal frequency division multiplexing OFDM. The fixed unit records a predetermined number of parameters relative to the communication in course, for the purpose of weighting said parameters, such as number of errors in the radio link and number of retransmissions or the like, and allocates to these parameters a probability level. The fixed unit allocates a probability level to each carrier frequency, so that it responds to a communication set-up request allocating the carrier frequency with the highest probability.