Patent ID: 8768417

Claim:
A radio base station comprising: a radio communication unit configured to transmit broadcast control data via radio communication resources including an antenna unit including a number of antennas, the broadcast control data being data common to a plurality of radio terminals executing radio communication with the radio base station and being used to control the radio communication; an acquisition unit configured to acquire quality information indicating quality of the radio communication between each of the plurality of radio terminals and the radio base station; and an identification unit configured to identify, from the plurality of radio terminals, a number of degraded radio terminals having the quality lower than a threshold value, based on the quality information acquired by the acquisition unit, wherein when the number of degraded radio terminals is one, the radio communication unit performs beam-forming transmission of the broadcast control data in the direction corresponding to the one degraded radio terminal identified by the identification unit, wherein, (a) when there are two or more degraded radio terminals, the radio communication unit divides the antennas of the antenna unit into antenna groups to be used for transmission of the broadcast control data by dividing the number of antennas by the number of degraded radio terminals, and (b) if the number of antennas divided by the number of degraded radio terminals is less than two, the radio communication unit excludes a degraded radio terminal having a highest quality from being considered a degraded radio terminal of the two or more degraded radio terminals, and (c) the radio communication unit repeats (a) and (b) until the number of antennas divided by a number of remaining degraded radio terminals is not less than two, and (d) then the radio communication unit performs beam-forming transmission of the broadcast control data in the direction corresponding to each of the remaining degraded radio terminals, by using each of the antenna groups obtained by the division.