An operation method of a transmitting device such as an access point providing wireless communication includes receiving a feedback of channel response information from an external communication device, generating a beam steering matrix based on the channel response information, generating a power allocation matrix based on an average SNR for each of a plurality of streams included in the channel response information, and performing beamforming on the external communication device based on the generated power allocation matrix and the generated beam steering matrix. The channel response information is a compressed beamforming feedback of multiple input multiple output single user beamforming. A first power allocated to a first stream, of which an average SNR is a first value, from among the plurality of streams is larger than a second power allocated to a second stream, of which an average SNR is a second value greater than the first value.