# US 12,010,068 B2 · Method and apparatus communication using beam-forming in wireless communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,010,068 B2 - Document ID: US12010068B2 - Status: Granted - Kind: B2 - Application number: 17/643,219 - Filed: 2021-12-08 - Published: 2022-07-14 - Granted: 2024-06-11 - Earliest claimed: 2021-01-11 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Junho Lee; Jaein Kim; Huiwon Je; Jinwon Choi - Web page: https://patentgrep.com/patent/US12010068B2 ## CPC - H04B 7/0691: {using subgroups of transmit antennas} - H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling} - H04B 7/0404: the mobile station comprising multiple antennas, e.g. to provide uplink diversity - H04B 7/0874: {using subgroups of receive antennas} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/0082: {at predetermined intervals} - H04B 7/0608: {Antenna selection according to transmission parameters} - H04L 25/0224: {using sounding signals} - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method of operating a wireless communication device including a plurality of antennas according to an exemplary embodiment of the present disclosure includes determining an antenna subset including at least one of the plurality of antennas, transmitting a sounding reference signal (SRS) switching signal to a base station through at least one antenna of the antenna subset, receiving a channel state information-reference signal (CSI-RS) transmitted using a first beam from the base station, selecting a precoding matrix indicator (PMI) based on the CSI-RS, transmitting the selected PMI to the base station, and receiving a signal transmitted from the base station through a second beam determined based on the SRS switching signal and the PMI. ## Claims ### Claim 1 A method of operating a wireless communication device including a plurality of antennas, the method comprising: determining a plurality of antenna subsets, each including at least two of the plurality of antennas; transmitting a sounding reference signal (SRS) switching signal, comprising a plurality of SRSs, to a base station through the plurality of antenna subsets sequentially in an order of a first one of the antenna subsets having a largest separation distance between the at least two antennas thereof to a last one of the antenna subsets having a shortest separation distance between the at least two antennas thereof; receiving a channel state information-reference signal (CSI-RS) transmitted from the base station through a first beam; selecting a precoding matrix indicator (PMI) based on the CSI-RS; transmitting the selected PMI to the base station; and receiving a signal, transmitted from the base station through a second beam determined based on the SRS switching signal and the PMI. ### Claim 2 (depends on 1) The method of claim 1, wherein the determining of the plurality of antenna subsets is performed when a number of SRS switching resources allocated by the base station for the SRS switching signal is less than a number of reception antennas of the wireless communication device. ### Claim 3 (depends on 1) The method of claim 1, wherein the determining of the plurality of antenna subsets is performed when a number of RF chains of the wireless communication device is less than a number of reception antennas of the wireless communication device. ### Claim 4 (depends on 1) The method of claim 1, further comprising: monitoring a gain value of the second beam; and determining a final antenna subset based on the monitored gain value of the second beam. ### Claim 5 (depends on 4) The method of claim 4, further comprising calculating the gain value of the second beam by at least one of power of a received signal, a signal to noise ratio (SNR) of a received signal, frequency efficiency, and decoding performance of a received signal. ### Claim 6 (depends on 4) The method of claim 4, wherein the sequential transmitting of the SRS switching signal is performed in sequential transmission periods of the SRS switching signal, the SRS switching signal being transmitted through a respective one of the plurality of antenna subsets in each of the transmission periods. ### Claim 7 (depends on 4) The method of claim 4, further comprising determining the antenna subset as a final antenna subset when the gain value of the monitored second beam exceeds a predetermined threshold value. ### Claim 8 (depends on 1) The method of claim 1, wherein the determining of the antenna subsets is performed without measuring spatial correlation between the plurality of antennas. ### Claim 9 (depends on 1) The method of claim 1, further comprising determining an antenna subset based on reinforcement learning. ### Claim 10 (depends on 4) The method of claim 4, further comprising: tracking the final antenna subset for each tracking period; and changing at least one antenna included in the antenna subset based on a tracking result. ### Claim 11 (depends on 1) The method of claim 1, comprising determining a final antenna subset based on at least one of a signal to interference plus noise ratio (SINR) of the wireless communication device, a transmission/reception characteristic of an antenna, and a linearity of a transmission power amplifier. ### Claim 12 (depends on 1) The method of claim 1, wherein the selecting of the PMI comprises selecting a PMI based on information on a weight applied to a CSI-RS reception channel. ### Claim 13 (depends on 1) The method of claim 1, wherein the selecting of the PMI comprises selecting a PMI based on reinforcement learning. ### Claim 14 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. ### Claim 15 (depends on 14) The wireless communication device of claim 14, wherein, when a number of SRS switching resources allocated by the base station for the SRS switching signal is less than a number of reception antennas of the wireless communication device, the processor is configured to determine an antenna subset. ### Claim 16 (depends on 14) The wireless communication device of claim 14, wherein, when a number of radio frequency (RF) chains of the wireless communication device is less than a number of reception antennas of the wireless communication device, the processor is configured to determine an antenna subset. ### Claim 17 (depends on 14) The wireless communication device of claim 14, wherein the processor is configured to sequentially determine each of a plurality of antenna subsets for each transmission period of the SRS switching signal. ### Claim 18 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. ### Claim 19 (depends on 18) The method of claim 18, wherein a gain value of the second beam is monitored by the wireless communication device, wherein a final antenna subset is determined by the wireless communication device based on the monitored gain value of the second beam.