Patent ID: 7813329

Claim:
A base station of a mobile communications system wherein a plurality of mobile stations that belong to adjacent cells and base stations that form the adjacent cells communicate by sharing a common frequency band, comprising: a receiving unit for receiving a base station identifier and a provisional downlink scrambling code that has been provisionally assigned, said base station identifier and provisional downlink scrambling code being sent from a base station control station; a scrambling code setting unit for setting up said received base station identifier and said received provisional downlink scrambling code; and a transmitting unit for spectrum-spreading the base station identifier by the provisional downlink scrambling code, and for transmitting the base station identifier; wherein the scrambling code setting unit assigns a lasting downlink scrambling code based on a reception report, and the reception report being transmitted by one of a plurality of mobile stations to an adjacent base station, the plurality of mobile stations belonging to a cell formed by the adjacent base station that is adjacent to the base station, the reception report being based on a reception of the provisional downlink scrambling code and the base station identifier, and the scrambling code setting unit assigns the lasting downlink scrambling code not only based on (i) the adjacent cell list of the base station showing a scrambling code of one of the adjacent base stations, but also based on (ii) adjacent cell lists of the adjacent base stations showing scrambling codes of remote base stations that are adjacent to said adjacent base station of the base station; wherein the scrambling code setting unit sets the lasting downlink scrambling code that is not a duplicate of any scrambling code used in the adjacent cell list of the base station, and in the adjacent cell lists of base stations that are adjacent to said base station.