A system and method for feeding back channel information are provided. A method for communications device operations includes generating feedback information, encoding the feedback information to produce a feedback payload, and transmitting the feedback payload to a communications server serving a communications device. The feedback information includes at least a first long term wideband channel statistics and a second long term wideband channel statistics.

A method for estimating a channel status by a base station in a wireless communication system according to an embodiment of the present invention comprises the steps of: obtaining an uplink channel matrix by using a sounding reference signal (SRS) received from a terminal; transmitting a channel state information-reference signal (CSI-RS) through at least some antenna devices in a two-dimensional antenna array of the base station; receiving a channel quality indicator (CQI) calculated on the basis of the CSI-RS transmission; and obtaining, through a predetermined correction factor obtained on the basis of the CQI and the uplink channel matrix, a downlink channel matrix for the entire two-dimensional antenna array comprising the remaining antenna devices through which the CSI-RS is not transmitted.

The teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for certain codebook reuse across different transmission scenarios, including for transmission from a single Uniform Linear Array (ULA) of transmit antennas and transmission from cross-polarized subgroups of such antennas. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder includes antenna-subgroup precoders of size N.sub.T/2, where N.sub.T represents the number of overall antenna ports considered. Correspondingly, the tuning precoder controls the offset of beam phases between the antenna-subgroup precoders, allowing the conversion precoder to be used with cross-polarized arrays of N.sub.T/2 antenna elements and with co-polarized arrays of N.sub.T antenna elements.

Various embodiments include an apparatus to be employed by an enhanced Node B (eNB), the apparatus comprising communication circuitry to receive, from a user equipment (UE), feedback information and control circuitry, coupled with the communication circuitry, to identify a codeword from a three-dimensional codebook based on the feedback information received from the UE, wherein the communication circuitry is further to precede data to be transmitted to the UE based on the codeword. An apparatus to be employed by a UE and additional methods are described.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit a first part of a channel state information (CSI) report, wherein the first part includes an indication of whether a value of a second part of the CSI report matches a value of a previous CSI report; and selectively transmit the second part of the CSI report based at least in part on whether the indication indicates that the value of the second part of the CSI report matches the value of the previous CSI report. In some aspects, a UE may determine a modified subband size of the UE, wherein the modified subband size is different than a configured subband size of the UE; and transmit, in a CSI report, an indication regarding the modified subband size to a base station. Numerous other aspects are provided.

Capability of a user equipment to support machine learning adaptation by a base station of a reference signal pattern is signaled between the base station and the user equipment. Configuration information from the base station indicates one or more of enabling or disabling of machine learning adaptation of the reference signal pattern, a machine learning model used for machine learning adaptation of the reference signal pattern, updated model parameters for the machine learning model, or whether model parameters received from the user equipment will be used for machine learning adaptation of the reference signal pattern. Model training may be performed or model parameters received, and reference signals are received from the base station. Information on a reference signal pattern may be transmitted by the user equipment to the serving base station. Assistance information may be transmitted by the user equipment to the base station, which configures a reference signal pattern.

The present disclosure relates to a method for determining a precoding matrix indicator, a user equipment (UE), a base station (e.g., eNB), and a system. The method includes: receiving a reference signal sent by a base station; selecting, based on the reference signal, a precoding matrix from a codebook, where a precoding matrix W included in the codebook is a product of two matrices W.sub.1 and W.sub.2, where W.sub.1 is a block diagonal matrix, where each block matrix is a Kronecker product of a matrix A.sub.i and a matrix B.sub.i; and sending a precoding matrix indicator (PMI) to the base station, where the PMI corresponds to the selected precoding matrix, so that the base station obtains the precoding matrix according to the PMI.

A user equipment (UE) in communication with a base station (BS) is disclosed that includes a receiver that receives Channel State Information (CSI)-Reference Signals (RSs) from the BS, a processor that generates CSI based on the CSI-RS and performs CSI omission, and a transmitter that transmits, to the BS, CSI reports including the CSI where one or more linear combination (LC) coefficients are omitted based on the CSI omission. Further, in the CSI omission, the processor prioritizes LC coefficients based on a predetermined priority rule and the processor also determines the omitted one or more LC coefficients based on the prioritized LC coefficients. In other aspects, a method for a UE and a wireless communication system are disclosed.

Systems and methods for multi-beam Channel State Information (CSI) reporting are provided. In some embodiments, a method of operation of a second node connected to a first node in a wireless communication network for reporting multi-beam CSI includes reporting a rank indicator and a beam count indicator in a first transmission to the first node. The method also includes reporting a cophasing indicator in a second transmission to the first node. The cophasing indicator identifies a selected entry of a codebook of cophasing coefficients where the number of bits in the cophasing indicator is identified by at least one of the beam count indicator and the rank indicator.

In this way, feedback for both a rank indicator and a beam count indicator may be possible which may allow robust feedback and variably sized cophasing and beam index indicators.

Provided are a method and an apparatus for reporting channel state information (CSI) by a user equipment in a wireless communication system. According to the present invention, the user equipment may receive configuration information related with the CSI from a base station and measure the CSI based on the configuration information. Thereafter, the user equipment includes reporting the CSI to the base station and the CSI includes a rank indicator (RI), a channel quality indicator (CQI), and an indicator indicating the number of amplitude coefficients other than 0 and the second part includes a precoding matrix indicator (PMI).