Method of automatic frequency assignment in a mobile communication system

Claim 1

An automatic frequency assignment method for a mobile communication system including a plurality of radio ports each of which constitutes a radio zone for communicating with a plurality of personal stations, and a radio port control unit connected to each of said plurality of radio ports and controlling said plurality of radio ports, said method assigning a radio frequency to be used by each of the plurality of radio ports comprising steps of: receiving signals at a first radio port to which a frequency to be used thereat will be assigned, said signals being transmitted from each of the other radio ports, and reporting the received signal power associated with corresponding frequency of each received signal to said radio port control unit; determining, at said radio port control unit, an assignment candidate frequency having the lowest received signal power based on the received signal power reported by said first radio port; transmitting, to said first radio port, a signal of said assignment candidate frequency from a plurality of selected radio ports located near said first radio port; verifying if any said radio port is being interfered with by said assignment candidate frequency by comparing said assignment candidate frequency with a threshold level; assigning said assignment candidate frequency to said first radio port if none of the selected radio ports do not report that said comparing exceeds said threshold; and not assigning said assignment candidate frequency to said first radio port if at least one said selected radio port reports that said comparing exceeds said threshold; and if said assignment candidate frequency is not assigned, determining at least one other assignment candidate frequency having the second lowest received signal power, and verifying an interference in any of said selected radio ports affected by the newly determined assignment candidate frequency.