Method for transmitting data in multiple antenna system

A data transmission method in a multiple antenna system, the method comprising:

• generating a transmit (Tx) signal in a plurality of antennas by applying a precoding weight matrix to first and second antenna clusters including the plurality of antennas, wherein:
• the precoding weight matrix is a block diagonal matrix that is configured with a precoding weight corresponding to the first antenna cluster and a precoding weight corresponding to the second antenna cluster;
• the precoding weight corresponding to the first antenna cluster is selected according to a channel condition;
• and
• the precoding weight corresponding to the second antenna cluster is different from the precoding weight corresponding to the first antenna cluster and is selected according to a specific rule irrespective of the channel condition in order to receive feedback data for only the first antenna cluster, the feedback data including a precoding matrix indicator (PMI);
• transmitting the Tx signal;
• and
• receiving the PMI for selection of the precodinq weight corresponding to the first antenna cluster,
• wherein:
• a whole frequency band includes a plurality of subbands each including a plurality of subcarriers;
• and
• the precodinq weight corresponding to the second antenna cluster is applied to each of the plurality of subbands.