The present invention relates to a method for transmitting channel state information regarding downlink transmission through an uplink may comprise the steps of: receiving a downlink signal through a downlink channel; generating a rank indicator (RI) for the downlink channel, a first precoding matrix indicator (PMI), and a second PMI, and generating channel quality information (CQI) on the basis of pre-coding information which is determined by a combination of the first and second PMIs; and transmitting the RI, first PMI, second PMI, and/or CQI through the uplink channel. The CQI may comprises a first type of CQI calculated on the basis of the number N of layers in which the downlink signal is received and/or a second type of CQI calculated on the basis of the assumption that the number of layers in which the downlink signal is transmitted is K (where K>N).