Patent ID: 8638845

Claim:
A channel state information compressing apparatus provided in a receiver of a MIMO system in which a transmitter precodes transmitted data based on information received from the receiver, wherein the channel state information compressing apparatus comprises: a time-to-frequency region converter that converts a region for channel state information which indicates a state of each communication channel from a time region to a frequency region, where the channel state information is a channel response matrix defined between a plurality of reception antennas of the receiver and a plurality of transmission antennas of the transmitter; and an adaptive selector that selects each frequency component to be included in compressed data based on electric power of the frequency component from among frequency region data obtained by the time-to-frequency region converter, wherein the adaptive selector selects a predetermined number of frequency components in order of an amount of the electric power from the largest to the smallest, wherein the channel state information compressing apparatus outputs the compressed data consisting of each selected frequency component, and information for identifying each frequency component which forms the compressed data.