Patent ID: 8626069

Claim:
A Base Station (BS) apparatus in a wireless communication system, the apparatus comprising: a first calculator configured to determine a degradation factor indicating a degradation degree of a target signal due to interference cancellation by using a target channel matrix h d and at least one interfering channel matrix; a second calculator configured to determine a new noise power value to be used to determine a beamforming vector if the degradation factor is greater than or equal to a threshold DF th , and configured to determine the beamforming vector by using the new noise power value; and a beamformer configured to perform beamforming on a signal transmitted/received with a target Mobile Station (MS) by using the beamforming vector, wherein the first calculator is configured to determine the degradation factor by calculating a signal power ratio of when a first beamforming vector that prioritizes a gain of the target signal is used to when a second beamforming vector that prioritizes interference cancellation is used, wherein the second calculator is configured to determine the new noise power value which increases according to at least one of: a signal power value of when the first beamforming vector is used, the threshold DF th , and a square of an absolute value of a result obtained by multiplying the target channel matrix h d by a component h ∥ parallel to the target channel matrix in the at least one interfering channel matrix, and wherein the second calculator is configured to calculate a Minimum Mean Square Error (MMSE) beamforming vector by using the new noise power value.