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.

Methods, network nodes and wireless device for setting an electrical tilt of an antenna array toward a distribution of wireless devices are disclosed. According to one aspect, a method includes for each of at least one sector of an area covered by the antenna array, determining a function of precoding matrix indicators, PMIs, received from a plurality of WDs in the sector. The method includes determining a current electrical tilt angle of the sector based on the function of PMIs. The method further includes comparing a difference between the current electrical tilt angle of the sector and a previously determined electrical tilt angle of the antenna array to a first threshold, and setting the electrical tilt angle of the antenna array based on the comparison.

A communication device for providing a channel state information, CSI, feedback in a wireless communication system includes a transceiver to receive a radio signal including downlink reference signals. The processor estimates an explicit CSI, selects a Doppler-delay precoder matrix for a composite Doppler-delay-beam three-stage precoder, calculates and reports to the transmitter a CSI feedback.

The communication device selects from one or more codebooks a subset of D delay components and/or a subset of F Doppler-frequency components and uses the selected subset of delay components for each polarization and each spatial beam and/or the selected subset of Doppler-frequency components for each polarization, each spatial beam and each delay, when calculating the Doppler-delay precoder matrix.

[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.

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.

A User Equipment (UE) receives, from a network node, codebook subset restriction (CBSR) signaling comprising a bitmap. The bitmap comprises a plurality of sets and each set comprises a plurality of bits. Each of the bits indicates whether a respective vector in a first set of vectors is restricted. Each set of bits indicates whether a respective vector in a second set of vectors is restricted. The UE restricts precoders selectable from a plurality of codebooks based on either a first vector in the first set of vectors or a second vector in the second set of vectors being indicated as restricted.

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.

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.

Beamforming communication systems with high linearity are provided. In certain embodiments, a method of beamforming includes generating a transmit signal using a baseband processor, providing digital pre-distortion to the transmit signal, generating a radio frequency input signal based on the transmit signal using a transceiver, processing the radio frequency input signal to generate a plurality of radio frequency output signals using a plurality of transmit signal paths of a front end system, providing analog pre-distortion to at least one of the plurality of transmit signal paths using the front end system, and radiating a transmit beam in response to receiving the plurality of radio frequency output signals using an antenna array.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may select a precoding matrix of orthogonal beams. The base station may precode a channel state information reference signal (CSI-RS) transmitted to a user equipment (UE) using the precoding matrix of orthogonal beams. The base station may receive, from the UE, one or more reports that indicate one or more beam indices selected from beam indices associated with the precoding matrix of orthogonal beams. Numerous other aspects are provided.