[Object] To provide a mechanism capable of more appropriately ascertaining an interference condition of a data signal. [Solution] An apparatus includes: a processing unit that feeds back a channel quality indicator (CQI) of a serving base station, which is calculated on a basis of results of measuring reference signals received from the serving base station and a neighbor base station and information related to a power difference between the reference signal and a data signal of the neighbor base station, to the serving base station.

A high frequency data network access system leverages commodity WiFi chipsets and specifically multi spatial stream (e.g., 802.11 ac) chipsets in combination with phased array antenna systems at the aggregation nodes. Examples can be very spectrally efficient with both polarization and frequency diversity.

A method for feeding back information about a channel between antenna arrays is provided, which includes: receiving, by a first network device, sub-channel channel information of NM sub-channels that is sent by a second network device, where an antenna array of the first network device includes M panels, an antenna array of the second network device includes N panels, the channel between the first network device and the second network device includes the NM sub-channels, M is a positive integer that is greater than or equal to 2, N is and N is a positive integer, M and N are not to be 1 at the same time, and the M panels and the N panels each includes at least two antennas; generating channel information of the channel between the first network device and the second network device according to the sub-channel channel information of the NM sub-channels.

A method, in a radio network node, comprises identifying, among a predetermined codebook of precoding matrix codewords, a subset of precoding matrix codewords that are not to be reported by the wireless device in channel-state-information, CSI, feedback, and transmitting, to the wireless device, a bitmap identifying the subset of precoding matrix codewords that are not to be reported by the wireless device; where each bit in the bitmap corresponds to only one combination of a first dimension index l.sub.1 and a second dimension index l.sub.2 out of the possible combinations of the first dimension index l.sub.1 and the second dimension index l.sub.2, and where the first dimension index l.sub.1 and the second dimension index l.sub.2 identify a two-dimensional beam, the two-dimensional beam being defined by a vector of complex numbers comprised within at least one column of a precoding matrix codeword in the codebook.

A method involving an antenna array for wirelessly transmitting information carried by a source signal stream that includes a plurality of individual transmit signal streams, the method involving: mapping the plurality of transmit signal streams to a plurality of individual beam signal streams, wherein at least one of the beam signal streams of the plurality of beam signal streams is a combination of multiple transmit signal streams of the plurality of transmit signal streams; using the antenna array to generate a plurality of transmit beams; and sending each beam signal stream of the plurality of beam signal streams over a different transmit beam of the plurality of transmit beams.

Disclosed herein a method of, at a user equipment (UE), reporting channel quality information for three-dimensional (3D) multiple input multiple output (MIMO) transmission to a base station in a wireless communication system The method includes receiving information for vertical cycling beamforming from the base station, calculating the channel quality information using the information for the vertical cycling beamforming, on the assumption that different vertical beamforming is circularly applied in a predetermined resource unit to receive a downlink signal, and reporting the calculated channel quality information to the base station.

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.

In accordance with an example embodiment of the present invention, a method comprising: selecting, by a user equipment, a subset of linear combination coefficients from a linearized two-dimensional matrix having columns of frequency domain components and rows of spatial beams components for channel state information determination, wherein the number of linear combination coefficients in the subset is less than all of the linear combination coefficients; determining indication comprising information associated with column indices of the selected subset of linear combination coefficients from the linearized two-dimensional matrix, wherein the indication excludes the index of the column with lowest index of the linearized two-dimensional matrix; determining compressed channel state information comprising locations in the linearized two-dimensional matrix of the subset of linear combination coefficients and corresponding values of the linear combination coefficients at those locations; and reporting, from the user equipment toward the base station, the compressed channel state information.

Methods and apparatuses for CSI reporting mechanisms are provided. A user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive information indicating a channel state information reference signal (CSI-RS) resource configuration, uplink-related downlink control information (DCI), and a CSI-RS associated with a selected CSI-RS resource in a same subframe as the uplink-related DCI. The processor configured to determine, in response to a CSI request included in the uplink-related DCI, an aperiodic CSI in reference to the CSI-RS. The transceiver is further configured to report the aperiodic CSI by transmitting the aperiodic CSI on an uplink channel.

A method and device for feeding back channel state information (CSI) by a user equipment (UE) in a wireless communication system applied three-dimensional (3D) beamforming. The method includes: receiving a pilot signal (reference signal) from a base station; configuring a CSI transmission mode in one of a first transmission mode and a second transmission mode based on motion information of the UE; and feeding back the CSI based on the configured CSI transmission mode. The first transmission mode transmits the CSI including precoding matrix index (PMI) information for one of vertical beamforming or horizontal beamforming. The second transmission mode transmits the CSI including PMI information for both vertical beamforming and horizontal beamforming.