The present invention according to one embodiment comprises the steps of: receiving linear-combination (LC) code word-based channel state reporting configuration, which is expressed by parameters comprising an LC coefficient and a phase differential (co-phase) value between antenna groups having mutually different polarization characteristics; measuring a downlink reference signal for a channel state reporting in accordance with the received channel state reporting configuration; and transmitting, to a base station, the LC code book-based channel state report corresponding to the reference signal measurement, wherein the channel state reporting can only support a broadband reporting mode.