Patent ID: 8396143

Claim:
A method for transmitting signals in a transmit end of a wireless communication system, the method comprising: generating a precode and a postcode for coordinated beamforming using channel information of a plurality of streams for transmitting signals to one or more receive ends; selecting the streams to be allocated pilots using the channel information of the streams, wherein selecting the streams comprises selecting a stream using a scheme selected from a group comprising a scheme of selecting a fixed stream, a scheme of selecting a stream maximizing a sum rate of the whole stream when transmitting pilots through respective streams, a scheme of selecting a stream having a greatest minimum value among signal levels measured at respective receive ends when transmitting a pilot through each stream, and a scheme of selecting a stream having a greatest signal level among signal levels to reach the one or more receive ends when transmitting pilots through respective streams; updating the precode according to a reference point representing an effective channel of non-selected streams orthogonal to an effective channel of the selected streams; and precoding the signals transmitted through the streams using the updated precode.