Abstract: A system and method are provided for determining whether to assign a macrocell communication frequency or a microcell communication frequency to a particular mobile communication terminal for a particular communication interval of a communication session. The speed of the mobile communication terminal is estimated immediately prior to the communication interval based upon the number of changes in the strength of signals received from the mobile communication terminal during a predetermined time interval. If the estimated speed is within a first predetermined range, one of the macrocell communication frequencies is assigned to the mobile communication terminal. If the estimated speed is within a second predetermined range, one of the microcell communication frequencies is assigned to the mobile communication terminal.