Patent ID: 9369193
Filing Date: 2016-06-14
CPC Classification: H04B,H04W

Claim Text:
1. A method for feeding back channel state information with respect to a downlink transmission by a user equipment in a wireless communication system supporting multiple antennas, the method comprising: transmitting a grouping index indicating whether antennas are vertically grouped or horizontally grouped, wherein the grouping index is determined based on channel correlation; performing a channel measurement for the downlink transmission; and transmitting a precoding matrix indicator (PMI) indicating precoding matrixes for multiple antennas, based on a result of the channel measurement, wherein the multiple antennas are grouped as N number of antenna groups corresponding to the grouping index, where N>0 and N is an integer, wherein the precoding matrixes for the multiple antennas are determined by N number of precoding matrixes for the antenna groups and phase coefficient matrixes corresponding to the N number of precoding matrixes for the antenna groups, and wherein the precoding matrixes for multiple antennas are configured to be applied by cyclic delay diversity (CDD) precoding according to the channel correlation.