A communication system capable of cooperatively transmitting a data from a first base station and a second base station by radio communication, wherein the first base station acquires a value of a transmission weight that is multiplied by a transmission signal from the first base station so as to suppress an interference from the second base station in a first communication terminal, by calculating the value of the transmission weight based on quality information on a radio signal received from the first communication terminal, when the first communication terminal having the first base station as a desired station locates in a cell border area between a cell of the first base station and a cell of the second base station, wherein the second base station replicates a second desired data for a second communication terminal having the second base station as a desired station located in a cell of the second base station, and transmits the replicated second desired data to the first base station via an inter-base station communication interface, wherein the first base station generates a transmission signal by multiplying the value of the transmission weight by a first desired data for the first communication terminal and the second desired data for the second communication terminal received from the second base station, in such a way that the second desired data multiplied by the transmission weight becomes opposite in phase to an interference signal from the second base station, wherein the second base station generates a transmission signal of the second desired data for the second communication terminal, and wherein the first base station cooperatively transmits the generated transmission signal of the first desired data and the second desired data after multiplying by the value of the transmission weight, at a predetermined data cooperative transmission timing, and the second base station cooperatively transmits the generated transmission signal of the second desired data, at the predetermined data cooperative transmission timing. wherein the first base station acquires a value of a transmission weight that is multiplied by a transmission signal from the first base station so as to suppress an interference from the second base station in a first communication terminal, by calculating the value of the transmission weight based on quality information on a radio signal received from the first communication terminal, when the first communication terminal having the first base station as a desired station locates in a cell border area between a cell of the first base station and a cell of the second base station, wherein the second base station replicates a second desired data for a second communication terminal having the second base station as a desired station located in a cell of the second base station, and transmits the replicated second desired data to the first base station via an inter-base station communication interface, wherein the first base station generates a transmission signal by multiplying the value of the transmission weight by a first desired data for the first communication terminal and the second desired data for the second communication terminal received from the second base station, in such a way that the second desired data multiplied by the transmission weight becomes opposite in phase to an interference signal from the second base station, wherein the second base station generates a transmission signal of the second desired data for the second communication terminal, and wherein the first base station cooperatively transmits the generated transmission signal of the first desired data and the second desired data after multiplying by the value of the transmission weight, at a predetermined data cooperative transmission timing, and the second base station cooperatively transmits the generated transmission signal of the second desired data, at the predetermined data cooperative transmission timing.