A method for transmitting a downlink signal through coordinated beamforming with a neighboring cell by a serving cell in a wireless communication system, the method comprising: transmitting, to the neighboring cell, first information for a first subframe set, which is restricted to report a first precoding matrix index, PMI, set, and second information for a second subframe set which is restricted to report a second PMI set; receiving, from the neighboring cell, feedback information requesting adjustment of a ratio between the first and the second subframe set based on a difference between a first channel quality indicator, CQI, of the first subframe set and a second CQI of the second subframe set; adjusting the ratio between the first and the second subframe set based on the feedback information; wherein the adjustment comprises decreasing the number of frames in the subframe set corresponding to the worse one of the first and second CQI; transmitting, to a User Equipment, UE, of the serving cell, third information related to a first Precoding Matrix Index, PMI, restriction for the first subframe set and fourth information for a second PMI restriction for the second subframe set, wherein each of the first and second PMI restrictions includes one or more PMIs, and wherein the one or more PMIs are used to form a beam so that interference affecting the neighboring cell in the first and second subframe sets has a constant characteristic with respect to intercell interference; receiving, from the UE of the serving cell, a first Channel State Information, CSI, reporting for the first subframe set based on the first PMI restriction and a second CSI reporting for the second subframe set based on the second PMI restriction; and transmitting, to the UE of the serving cell, a downlink signal based on the first CSI reporting and the second CSI reporting, wherein the feedback information is transmitted, by the neighboring cell, when the difference between the first and the second CQIs is greater than a threshold value, and wherein the first and the second CQIs are measured by the UE of the neighboring cell in the first and the second subframe sets. transmitting, to the neighboring cell, first information for a first subframe set, which is restricted to report a first precoding matrix index, PMI, set, and second information for a second subframe set which is restricted to report a second PMI set; receiving, from the neighboring cell, feedback information requesting adjustment of a ratio between the first and the second subframe set based on a difference between a first channel quality indicator, CQI, of the first subframe set and a second CQI of the second subframe set; adjusting the ratio between the first and the second subframe set based on the feedback information; wherein the adjustment comprises decreasing the number of frames in the subframe set corresponding to the worse one of the first and second CQI; transmitting, to a User Equipment, UE, of the serving cell, third information related to a first Precoding Matrix Index, PMI, restriction for the first subframe set and fourth information for a second PMI restriction for the second subframe set, wherein each of the first and second PMI restrictions includes one or more PMIs, and wherein the one or more PMIs are used to form a beam so that interference affecting the neighboring cell in the first and second subframe sets has a constant characteristic with respect to intercell interference; receiving, from the UE of the serving cell, a first Channel State Information, CSI, reporting for the first subframe set based on the first PMI restriction and a second CSI reporting for the second subframe set based on the second PMI restriction; and transmitting, to the UE of the serving cell, a downlink signal based on the first CSI reporting and the second CSI reporting, wherein the feedback information is transmitted, by the neighboring cell, when the difference between the first and the second CQIs is greater than a threshold value, and wherein the first and the second CQIs are measured by the UE of the neighboring cell in the first and the second subframe sets.