A method and user equipment (UE) are provided for reporting channel state information (CSI). The UE supports massive multiple-input multiple-output (MIMO) technology in a wireless communication system. The UE receives, from an eNode B, M port CSI reference signals through a plurality of antenna ports composed of an L×M array, where L corresponds to a number of antenna ports in a horizontal direction and M corresponds to a number of antenna ports in a vertical direction. The UE selects a vertical antenna port by comparing energy of the M port CSI reference signals, and calculates a rank indicator (RI), precoding matrix indicator (PMI), and a channel quality indicator (CQI) of the selected vertical antenna port based on the M port CSI reference signals. The UE transmits the calculated RI, the calculated PMI and the calculated CQI to the eNode B.

A communication system, a terminal apparatus, a base station apparatus, and a method for sharing a codebook are provided that make it possible to improve system capacity by using precoding according to a cell environment. In a communication system in which beam directivity control is performed by precoding using a codebook that is common between a base station (10) and a terminal (20), the base station (10) notifies the terminal (20) information for codebook determination k including cell (11)-specific information on the base station, and the base station (10) and the terminal (20) generate the common codebook based on the information for codebook determination.

According UE is configured to receive a channel state information reference signal (CSI-RS) from an evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB), determine channel state information based on the CSI-RS, and send the channel state information to the eNB. The channel state information includes a precoding matrix indicator corresponding to a first precoding matrix. The UE is also configured to receive a UE specific reference (UE-RS) signal and a physical downlink shared channel (PDSCH) signal. The UE-RS is precoded with a second precoding matrix. The UE estimates a UE-RS effective channel including the second precoding matrix based on the UE-RS and decodes data from the PDSCH signal based on an the first precoding matrix and the UE-RS effective channel.

Some techniques for implementing estimation of channel states with high accuracy and efficient feedback of the channel states in 3D MIMO are disclosed. One aspect of the present invention relates to user equipment for implementing 3D MIMO (3-Dimensional Multiple-Input Multiple-Output) communication, comprising: a channel state information generation unit configured to measure channel states of antenna ports of 3D MIMO antennas in a base station with reference signals transmitted from the antenna ports and generate channel state information based on the measured channel states; and a channel state information feedback unit configured to use different channel state information feedback means for antenna ports in respective dimensions of the antennas to feed the generated channel state information back to the base station.

The present invention relates to a method and an apparatus for transmitting, by a base station, a reference signal in a wireless communication system supporting a multi-antenna consisting of a plurality of horizontal domain antennas and a plurality of vertical domain antennas. Specifically, the method comprises the steps of: configuring, as a cell-specific reference signal (CRS) port, M first antenna ports among a total of N antennas that the base station has (where N and M are positive integers, N>M); transmitting a CRS using the M first antenna ports and transmitting a demodulation reference signal (DM-RS) using 0 second antenna ports (where 0 is a positive integer, N>O), to a terminal; and receiving channel measurement information using the CRS and the DM-RS which is fed back from the terminal.

The present invention relates to a base station in a wireless communication system which supports multi-antennas with multiple horizontal domains and multiple vertical domains. Particularly, the present invention comprises: a radio frequency unit and a processor, wherein the radio frequency unit comprises a first radio frequency (RF) chain and a second radio frequency (RF) chain which are connected to antenna elements corresponding to multiple vertical antennas with specific horizontal domains, wherein the processor, connected to the radio frequency unit, is configured to transmit reference signals, and wherein the first RF chain and the second RF chain are configured for different reference signals.

Methods and corresponding apparatuses for wireless communication are disclosed. The method for wireless communication includes dividing a two-dimensional antenna array to a plurality of sub-arrays, mapping the two-dimensional antenna array into a one-dimensional vertical channel state information reference signal (CSI-RS) port array for receiving elevation CSI feedback and a one-dimensional horizontal CSI-RS port array for receiving azimuth CSI feedback, and transmitting one or more elevation CSI-RS from the one-dimensional vertical CSI-RS port array and one or more azimuth CSI-RS from the one-dimensional horizontal CSI-RS port array. Methods and corresponding apparatuses for CSI feedback mechanism are also disclosed.

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 and apparatus for indicating DM-RS information and a communication system, applicable to a 3D MIMO system. The method includes: transmitting, by a base station, signaling indicating DM-RS information to UE. Hence, the UE may support high-dimension MU-MIMO according to the signaling.

The present disclosure provides a CSI feedback method, a CSI feedback device and a CSI feedback system. The CSI feedback method includes steps of: configuring, by a network side device, a first downlink channel measurement pilot for a UE; and receiving, by the network side device, first PMI information fed back by the UE. The first PMI information is acquired by the UE based on measurement of the first downlink channel measurement pilot and second PMI information. A dimension represented by the first PMI information is different from a dimension represented by the second PMI information.