Abstract: Methods and apparatuses in a wireless communication system. A method of operating a base station (BS) includes receiving a set of uplink signals; estimating, based on a subset of the set of uplink signals, uplink channels; estimating a timing offset (TO) and a frequency offset (FO) for a subset of the estimated uplink channels; compensating, based on the estimated TO and FO, the subset of the estimated uplink channels to generate TO and FO compensated uplink channel estimates; and generating channel prediction information based on the compensated subset of the estimated uplink channels.

Abstract: A method for a user equipment (UE) is provided. The method comprises receiving, from a base station (BS), information via a dynamic signaling comprising at least one of a medium access control channel element (MAC CE) or downlink control information (DCI) that includes information for a set of channel state information-reference signal (CSI-RS); identifying CSI-RS resources each of which comprises a set of antenna ports based on the information; and measuring CSI using an aggregation of the CSI-RS resources, wherein an energy per resource element (EPRE) ratio between a CSI-RS and a physical downlink shared channel (PDSCH) is configured in the information to each of the CSI-RS resources comprising the aggregated CSI-RS resources.

Abstract: A method of a base station (BS) in a wireless communication system is provided, The method comprises: receiving, from a user equipment (UE), a 1st layer sounding reference signal (SRS); arranging the 1st layer SRS based on two antenna polarizations of an antenna system of the BS; identifying a dominant direction of a channel based on the 1st layer SRS; identifying a coefficient between two antenna polarizations based on the 1st layer SRS; constructing a 2-layer channel matrix based on the identified dominant direction and the identified coefficient; and transmitting, to the UE, a downlink signal via the antenna system based on the constructed 2-layer channel matrix.

Abstract: A base station, method, and computer-readable storage medium for channel state information (CSI) acquisition. The base station includes a transceiver configured to transmit a first, unprecoded channel state information reference signal (CSI-RS) on a first antenna dimension; receive a first CSI report on the first antenna dimension; transmit a second, precoded CSI-RS on a second antenna dimension; and receive a second CSI report on the second antenna dimension. The first CSI report includes a precoding matrix index (PMI), a rank indicator (RI), and channel quality indicator (CQI) for the first antenna dimension; and the second CSI report comprises a PMI, a RI, and a CQI for the second antenna dimension. The base station also includes a processor operably connected to the transceiver, the processor configured to generate a downlink (DL) CSI for multi-user multi-input, multi-output (MU-MIMO) scheduling and precoding based on the first CSI report and the second CSI report.

Abstract: Reciprocity base frequency division duplex (FDD) multiple-input-multiple-output (MIMO) downlink (DL) channel Channel-State Information (CSI) acquisition is provided. A base station (BS) includes a transceiver configured to measure uplink (UL) sounding reference signals (SRSs) at a UL carrier frequency, using two polarization components of an antenna array of the BS, and a processor configured to determine a quantity of propagation paths between the BS and a user equipment (UE), for each of the determined propagation paths, extract propagation parameters from the UL SRS measurements, for each of the determined propagation paths, predict a downlink (DL) channel based on the extracted propagation parameters and a DL carrier frequency, and generate a precoding channel matrix for the UE by summing the predicted DL channels for each of the determined propagation paths and for each of the two polarization components of the antenna array of the BS.

Abstract: A base station for generating multi-user precoders. The base station includes a transceiver configured to receive sounding reference signals (SRSs) from a set of user equipments (UEs), and a processor configured to select, for one or more UEs in the set of UEs, one or more codewords from an uplink codebook based on a correlation between the one or more codewords and the one or more SRSs; determine, using a composite downlink codebook, downlink codewords for the selected uplink codewords, respectively, the composite downlink codebook mapping uplink codewords to downlink codewords based on steering angles derived from the uplink codewords; transmit a set of pre-coded channel state information reference signals (CSI-RSs) to the one or more UEs, wherein the pre-coded CSI-RSs are pre-coded based on the determined downlink codewords; and identify a downlink channel matrix based on CSI feedback from the one or more UEs and the pre-coded CSI-RSs.

Abstract: A method of a base station (BS) in a wireless communication system is provided, The method comprises: receiving, from a user equipment (UE), a 1st layer sounding reference signal (SRS); arranging the 1st layer SRS based on two antenna polarizations of an antenna system of the BS; identifying a dominant direction of a channel based on the 1st layer SRS; identifying a coefficient between two antenna polarizations based on the 1st layer SRS; constructing a 2-layer channel matrix based on the identified dominant direction and the identified coefficient; and transmitting, to the UE, a downlink signal via the antenna system based on the constructed 2-layer channel matrix.

Abstract: Base station (BS) capable of beamforming in a wireless communication includes a transceiver comprising an antenna array, the transceiver configured to measure SRS from a UE, using at least one portion of the antenna array, and a processor configured to select at least one UL beam vector based on an SRS measurement from a UL beam-codebook comprising a set of beam weight vectors, determine at least one DL beam weight vector corresponding to each of the selected at least one UL beam weight vector, transmit a beamformed CSI-RS by applying the at least one DL beam weight vector to the antenna array, receive a CSI feedback including a PMI from the UE, wherein the PMI is determined based on the beamformed CSI-RS, and construct a precoding channel matrix for the UE based on the PMI and the at least one DL beam weight vector.

Abstract: Base station (BS) capable of beamforming in a wireless communication includes a transceiver comprising an antenna array, the transceiver configured to measure SRS from a UE, using at least one portion of the antenna array, and a processor configured to select at least one UL beam vector based on an SRS measurement from a UL beam-codebook comprising a set of beam weight vectors, determine at least one DL beam weight vector corresponding to each of the selected at least one UL beam weight vector, transmit a beamformed CSI-RS by applying the at least one DL beam weight vector to the antenna array, receive a CSI feedback including a PMI from the UE, wherein the PMI is determined based on the beamformed CSI-RS, and construct a precoding channel matrix for the UE based on the PMI and the at least one DL beam weight vector.

Abstract: An apparatus for performing a wireless communication includes a communication interface configured to measure uplink (UL) Sounding Reference Signals (SRSs) transmitted from a mobile client device, and at least one processor configured to buffer a number of uplink (UL) SRS measurements derived from UL SRS transmissions of the mobile client device, the number of UL SRS measurements exceeding a threshold, extract features from UL SRS measurements, obtain a machine learning (ML) classifier for determining a category to be used for estimating mobility associated with the mobile client device, and determine the category of the mobile client device by applying the extracted features to the ML classifier. Methods and apparatus extract the features of either a set of power spectrum density measurements or a set of pre-processed frequency domain real and imaginary portions of UL SRS measurements and feed the features to an AI classifier for UE speed estimation.

Abstract: Reciprocity base frequency division duplex (FDD) multiple-input-multiple-output (MIMO) downlink (DL) channel Channel-State Information (CSI) acquisition is provided. A base station (BS) includes a transceiver configured to measure uplink (UL) sounding reference signals (SRSs) at a UL carrier frequency, using two polarization components of an antenna array of the BS, and a processor configured to determine a quantity of propagation paths between the BS and a user equipment (UE), for each of the determined propagation paths, extract propagation parameters from the UL SRS measurements, for each of the determined propagation paths, predict a downlink (DL) channel based on the extracted propagation parameters and a DL carrier frequency, and generate a precoding channel matrix for the UE by summing the predicted DL channels for each of the determined propagation paths and for each of the two polarization components of the antenna array of the BS.

Abstract: A method for a user equipment (UE) is provided. The method comprises receiving, from a base station (BS), information via a dynamic signaling comprising at least one of a medium access control channel element (MAC CE) or downlink control information (DCI) that includes information for a set of channel state information-reference signal (CSI-RS); identifying CSI-RS resources each of which comprises a set of antenna ports based on the information; and measuring CSI using an aggregation of the CSI-RS resources, wherein an energy per resource element (EPRE) ratio between a CSI-RS and a physical downlink shared channel (PDSCH) is configured in the information to each of the CSI-RS resources comprising the aggregated CSI-RS resources.