Method and apparatus communication using beam-forming in wireless communication system

A wireless communication device comprising:

• a plurality of antennas;
• a radio-frequency integrated circuit (RFIC) including a switching network connected to the plurality of antennas, wherein the switching network is configured to transmit a sounding reference signal (SRS) switching signal, comprising a plurality of SRSs, to a base station through at least one antenna of an antenna subset of the plurality of antennas;
• and
• a processor configured to:
• determine the antenna subset based at least in part on a linearity of a transmission power amplifier;
• select a precoding matrix indicator (PMI) to be provided to the base station based on a channel state information-reference signal (CSI-RS) transmitted from the base station through a first beam;
• and
• process a signal transmitted from the base station through a second beam determined based on the SRS switching signal and the PMI,
• wherein the processor is configured to monitor a gain value of the second beam and determine a final antenna subset based on the monitored gain value of the second beam.

A method of operating a base station communicating with a wireless communication device including a plurality of antennas, the method comprising:

• receiving a sounding reference signal (SRS) switching signal, comprising a plurality of SRSs, transmitted through a plurality of antenna subsets sequentially in an order of a first one of the antenna subsets having a largest separation distance between at least two antennas thereof to a last one of the plurality of subsets having a shortest separation distance between at least two antennas thereof;
• estimating uplink channel information based on the SRS switching signal;
• estimating downlink channel information based on the estimated uplink channel information;
• determining and forming a first beam based on the estimated downlink channel information, wherein a channel state information-reference signal (CSI-RS) is transmitted through the first beam;
• receiving a precoding matrix indicator (PMI) from the wireless communication device;
• and
• determining and forming a second beam based on the received SRS switching signal and the received PMI, wherein a signal including data is transmitted through the second beam.