[Object] To enable more appropriate recognition of an interference situation of a directional beam. [Solution] Provided is an apparatus including: an acquisition unit that acquires a weight set for forming a directional beam; and a control unit that multiplies a reference signal for channel quality measurement by the weight set. The weight set is a weight set that is able to be generated from a first weight set for acquiring directivity in a first direction, a second weight set for acquiring directivity in a second direction, and a third weight set for phase adjustment of dual layer multiple-input multiple-output (MIMO). The third weight set is a specific one of a plurality of weight sets for phase adjustment of dual layer MIMO.

Dynamic reconfiguration of CSI-RS resources for CSI reporting is described for full dimension multiple input, multiple output (FD-MIMO) systems. While a larger number of channel state information (CSI) reference signal (CSI-RS) resources with independent resource configuration are configured and associated with a CSI process, only a subset of resources that are activated by additional signaling are used for CSI measurement and reporting. The set of activated CSI-RS resources may include only a single CSI-RS resource. Both periodic and aperiodic CSI reporting may then be based on the same set of the activated CSI-RS resources. Medium access control (MAC) control elements may be used to provide activation/deactivation of the CSI-RS resources. Additionally, CSI reporting may be based on both the activated CSI-RS resources and the associated number of antenna ports.

Enhanced channel state information (CSI) feedback is disclosed for full dimensional multiple input, multiple output (FD-MIMO) operations. In one aspect, a CSI process is defined that may be used to identify an azimuth and elevation CSI-reference signal (RS) ports. A user equipment (UE) will send a precoding matrix indictor (PMI) report including a precoding matrix indicator (PMI) for the azimuth ports and a PMI for the elevation ports. One of the PMIs is assigned a low rank. The base station will use the two PMIs to create a whole channel precoding matrix. In another aspect, a single CSI process is configured having a plurality of CSI-RS resources. The UE generates channel measurement information for each of the CSI-RS resources, but only sets a CSI report to the base station of a subset of the total number of resources.

A transmitter includes a 3-dimensional antenna array including a plurality of antenna elements, each antenna element having a radiation pattern, wherein the radiation patterns mutually overlap. The plurality of antenna elements is adapted for coherent wireless communication in a wireless communication system. The 3D-antenna array includes first and second and third antenna elements spanning a 2-dimensional antenna plane, and includes a fourth antenna element arranged outside the 2-dimensional antenna plane; or the 3D-antenna array includes a first antenna element configured to direct a transmitted signal into a first direction, and a second antenna element configured to direct a transmitted signal into a second direction and not into the first direction. The transmitter further includes a precoder connected through the 3D-antenna array, to form one or more transmit beams and/or receive beams with the 3D-antenna array.

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.

The present invention relates to a method and a device for beamforming, and, more particularly, to a method and a device for transmitting a downlink signal by using a two-dimensional active array antenna in a wireless communication system. In order to achieve the objective mentioned above, a beamforming method by a base station in a mobile communication system, according to one embodiment of the present invention, comprises the steps of: receiving an uplink signal from at least one terminal; determining directivity information of a vertical channel of a downlink for the at least one terminal on the basis of the uplink signal; and performing resource scheduling and beamforming for the at least one terminal on the basis of the directivity information of the vertical channel of the downlink and channel status information in a horizontal direction received from the at least one terminal. According to an embodiment of the present invention, since a base station can estimate vertical channel information by using an uplink signal, it is possible to provide three-dimensional beamforming to terminals even without receiving the vertical channel information directly from the terminals, and thus the signal quality of each user can be improved and the efficiency of spatial multiplexing in a cell can be increased to thereby increase the total network capacity.

Disclosed are a method for transmitting/receiving channel state information in a wireless communication system and an apparatus for the same. Particularly, a method for reporting channel state information (CSI) by a user equipment (UE) in a wireless communication system may comprise the steps of: receiving channel state information reference signal (CSI-RS) from a base station through a multi-antenna port; and reporting CSI to the base station, wherein the CSI includes selection information indicating multiple codewords used to generate a precoding matrix within a codebook for reporting the CSI, a power coefficient and a phase coefficient are applied to each of the multiple codewords and the precoding matrix is then generated on the basis of a linear combination of the multiple codewords to each of which the power and phase coefficients are applied, and the selection information and information indicating the power coefficient are transmitted at different CSI reporting instances.

Example embodiments are presented for codebook subset restriction and precoder selection in wireless communications systems. For instance, an example method for codebook subset restriction at a user equipment (UE) is presented. In the example method, the UE can receive, from a network node such as a gNB, codebook subset restriction (CBSR) signaling for a first component common to precoders in a first group of codebooks. In an aspect of the present disclosure, a restriction of the first component maps to a restriction of a second component and the second component is common to precoders in a second group of codebooks. In addition, the example method includes restricting precoders selectable from a codebook in the second group of codebooks based on the second component. Network-side methods are presented, as well as example UEs and network nodes.

Disclosed are a codebook-based signal transmission and reception method in a multi-antenna wireless communication system and an apparatus therefor. Specifically, a method for transmitting or receiving a signal on the basis of a codebook by a terminal in a 2-dimensional multi-antenna wireless communication system comprises the steps of: receiving a channel state information reference signal (CSI-RS) through a multi-antenna port from a base station; and reporting channel state information to the base station, wherein the channel state information may include a precoding matrix indicator (PMI) for indicating a precoding matrix, the PMI may include a first PMI for selecting a set of precoding matrixes from the codebook and a second PMI for determining one precoding matrix applied to a multi-layer from the set of precoding matrixes, the precoding matrix may be configured by a precoding vector applied to each layer, and the precoding vector may be determined in the set of precoding vectors determined by the first PMI.

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.