The present application discloses a method for feeding back channel state information (CSI), comprising: acquiring first and second CSI based on a first and a second CSI measurement resource respectively, obtaining a channel quality indicator (CQI) based on the first CSI and the second CSI, wherein the first CSI comprises a first and a second type of precoding matrix indicator (PMI1 and PMI2) and a first rank indicator (RI1), and the second CSI comprises a first and a second type of PMI (PMI3 and PMI4) and a second RI (RI2); and feeding back third CSI to a base station, wherein the third CSI comprises third PMI information, third RI information, and the CQI, wherein the third PMI information is obtained based on at least three of the PMI1, the PMI2, the PMI3, and the PMI4, and the third RI information is obtained based on the RI1 and the RI2.

The present invention provides a method for reporting channel status information (CSI) for downlink transmission to an eNode B (eNB) by a user equipment (UE) in a wireless communication system. Specifically, the method comprises the steps of: receiving a channel status information-reference signal (CSI-RS) from the eNB; calculating the CSI on the basis of the CSI-RS under the assumption that a dual-precoder including a first precoder and a second precoder is applied; and reporting the CSI to the eNB, wherein the step of calculating the CSI includes a step for assuming that at least one of the first precoder and the second precoder is cyclically employed from a predetermined precoder candidate set on the basis of a predetermined resource unit; and information associated with the at least one precoder and information associated with the predetermined precoder candidate set are provided from the eNB through radio resource control (RRC) layer signaling.

For CSI reporting mechanisms, a user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive channel state information (CSI) process configuration information including at least one beamformed type associated with a plurality of non-zero-power (NZP) CSI reference signal (CSI-RS) resource configurations and receive a CSI-RS resource index (CRI) reporting configuration. The processor is configured to calculate, in response to receipt of the configuration information, a CRI and a channel quality indicator (CQI). The transceiver is further configured to report the CRI and the CQI by transmitting the CRI and the CQI on an uplink channel.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE determines priority levels of a plurality of messages based on at least one predetermined rule. The plurality of messages contain channel state information to be reported to a base station. The at least one predetermined rule specifies that a message including an indicator indicating at least one of a beam selection at a particular dimension and an orthogonal beam group selection has a priority level higher than a priority level of a message including an indicator indicating at least one of a beam direction from a group of beam candidates or co-phasing between two sets of antennas for two polarizations. The UE sends, to the base station, one or more messages of the plurality of messages based on the priority levels of the plurality of messages.

A CSI feedback method, a CSI acquisition method, a CSI feedback device and a CSI acquisition device are provided, so as to reduce pilot resources configured for a UE and reduce the difficulty in processing CSI progresses at a UE side, thereby to facilitate the CSI feedback and acquisition and save resources. The CSI acquisition method includes steps of: determining beamforming array information in a first dimension; beamforming a pilot signal in a second dimension in accordance with the beamforming array information in the first dimension, and transmitting the beamformed pilot signal in the second dimension to a UE through a pilot resource in the second dimension; and receiving, from the UE, CSI in the second dimension obtained by measuring the pilot signal in the second dimension.

A method for a terminal transmitting channel state information (CSI) in a wireless access system that supports massive multiple-input multiple-output (MIMO) according to one embodiment of the present invention may comprise the steps of: receiving CSI configuration information for reporting CSI; and transmitting CSI and identification information with respect to the partial channel corresponding to the CSI of the full channel according to the massive MIMO, on the basis of the CSI configuration information.

Disclosed are feedback and transmission devices and methods in full-dimension multi-antenna systems using two-dimensional (2D) planar array antennas, wherein a UE estimates channel states each corresponding to a respective one of multiple domain channels by a reference signal received from a base station, and obtains precoding matrix indicators (PMIs) each corresponding to a respective one of the multiple domain channels and rank indicators (RIs) each corresponding to a respective one of the multiple domain channels based on the estimated channel states. The UE may determine a joint rank indicator (JRI) using the obtained PMIs and the RIs and transmit feedback information containing the determined JRI to the base station.

To provide a base station apparatus, a terminal apparatus and a communication method which enable improvements in throughput and communication quality while suppressing an increase in complexity even in a case that the accuracy of a CSI report is improved. A terminal apparatus is provide with: a receiver configured to receive a CSI-RS and configuration information of a CSI report; and a transmitter configured to transmit CSI relating to the CSI-RS, wherein the CSI includes a first PMI and a second PMI, the first PMI is an indicator indicating multiple vectors, the second PMI includes either or both of a first indicator and a second indicator, the first indicator is an indicator indicating one or more complex weights of a first dimension for the multiple vectors, the second indicator is an indicator indicating one or more complex weights of a second dimension for the multiple vectors, and configuration information of the CSI report includes information indicating whether or not the second PMI includes the first indicator.

A wireless communication device including a control unit configured to generate information for a terminal device based on information acquired from the terminal device. The control unit outputs a reference signal on a first beam generated with at least two or more different first weighting matrices, generates a second weighting matrix specific to a terminal device in accordance with information transmitted from the terminal device in accordance with the reference signal, and outputs data for the terminal device on a second beam with the first weighting matrices and the second weighting matrix. The wireless communication device can supply an appropriate beam to a terminal device while preventing a problem with overhead or increase in the cost of a wireless device, which are caused by an increasing number of antenna elements when FD-MIMO is used.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitter device may determine an adapted codebook for beamforming transmission based at least in part on an initial codebook and one or more spatial parameters, wherein the adapted codebook is associated with an adapted set of candidate beams with an adapted angular range that is different than an initial angular range of an initial set of candidate beams of the initial codebook. In some aspects, the transmitter device may transmit using at least one beam of the adapted set of candidate beams associated with the adapted angular range based at least in part on determining the adapted codebook. Numerous other aspects are provided.