Patent ID: 9635642
Date: 2017-04-25
CPC Classifications: H04B,H04L,H04W

Claim:
1. A beamforming method of a transmitter using a plurality of antenna ports in a wireless communication system, the beamforming method comprising: generating signals for beams to be transmitted through corresponding antenna ports; forming the beams by precoding the signals with beamforming vectors; sorting the beams into a plurality of resource reuse groups which share a channel state information reference signal (CSI-RS) resource; transmitting, to a receiver, CSI-RSs using the beams on CSI-RSs resources determined based on the resource reuse groups, a plurality of beams included in one of the resource reuse groups being transmitted in one of the CSI-RSs resources; selecting a beam based on feedback information on the CSI-RSs transmitted by the receiver; and allocating a transmission resource for the selected beam, wherein selecting the beam comprises: receiving an index of one of the resource reuse groups having a greatest gain in association with a downlink channel and a beamforming vector, from the receiver; estimating an uplink spatial correlation matrix using an uplink Sounding Reference Signal (SRS) transmitted by the receiver; calculating an average channel gain on downlink channels using the estimated uplink spatial correlation matrix; and determining the beam having the greatest gain for the transmitter from among the plurality of beams included in the one of the resource reuse groups having the index and the average channel gain on the downlink channels.