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.

Embodiments of the present disclosure provide a signal transmission method, network device, and terminal device. The method includes: determining a first time-frequency resource; obtaining a second time-frequency resource and a third time-frequency resource based on the first time-frequency resource and a preset rule, where the third time-frequency resource includes at least one resource element (RE) at a predefined location in the first time-frequency resource, the second time-frequency resource includes a resource other than the third time-frequency resource in the first time-frequency resource, the preset rule indicates the predefined location, the second time-frequency resource is used to carry a beamformed control channel, and the third time-frequency resource is used to carry a reference signal of the beamformed control channel.

A method of identifying reference signal resources to be used in a transmission by a wireless device is disclosed. The method comprises a wireless device receiving signaling configuring the wireless device with a plurality of reference signal resource groups, each group comprising a plurality of reference signal resources. The wireless device subsequently receives an indication, in a control channel, of a selection of reference signal resources to be used. Each of the plurality of reference signal resources to be used is selected from a different one of the plurality of reference signal resource groups such that reference signal resources belonging to the same reference signal resource group are not selected for simultaneous use. A reference signal is then transmitted to a network node in the network using the indicated selection of reference signal resources.

Disclosed are techniques for using a channel state information (CSI) report framework to support positioning measurements in a wireless network. More particularly, a base station may identify one or more reference signal resources to be transmitted to a user equipment (UE) for obtaining at least one positioning measurement and configure the reference signal resources to be transmitted at least partially outside a current bandwidth that the base station and the UE are using to communicate data and control information. Accordingly, the base station may transmit, to the UE, a CSI report setting that indicates the positioning measurement to be reported and specifies that the positioning measurement is to be obtained from the configured reference signal resources.

Certain aspects of the present disclosure provide techniques for beam refinement procedures including dynamic signaling and/or selection of beam-switching latency for beam refinement procedures using inter- and/or intra-antenna module beam switching. A method by a base station (BS) includes configuring a user equipment (UE) with one or more reference signal (RS) resource sets. Each of the one or more RS resource sets is associated with a first or second type of beam refinement procedure. The BS receives an indication from the UE of at least a first latency and a second latency, longer than the first latency. The BS dynamically selects, for each RS transmission using one of the configured resource sets, the first or second latency. The BS sends the RS transmissions at the selected latency with respect to downlink control information (DCI) triggering the RS transmissions for the first or second type of beam refinement procedure.

Systems and methods for multi-beam Channel State Information (CSI) reporting are provided. In some embodiments, a method of operation of a second node connected to a first node in a wireless communication network for reporting multi-beam CSI includes reporting a rank indicator and a beam count indicator in a first transmission to the first node. The method also includes reporting a cophasing indicator in a second transmission to the first node. The cophasing indicator identifies a selected entry of a codebook of cophasing coefficients where the number of bits in the cophasing indicator is identified by at least one of the beam count indicator and the rank indicator.

In this way, feedback for both a rank indicator and a beam count indicator may be possible which may allow robust feedback and variably sized cophasing and beam index indicators.

Methods, systems, and devices for channel state information feedback based on full channel estimation are described. The method may include receiving a set of beamformed reference signals from a transmit device via a set of receive beams of the receive device, each beamformed reference signal of the set of beamformed reference signals associated with a corresponding transmit beam of a set of transmit beams of the transmit device, determining, based on the set of beamformed reference signals, a channel matrix representative of a communications channel between the receive device and the transmit device, and transmitting, to the transmit device, channel state information based on the channel matrix.

An apparatus for wireless communication includes a memory and one or more processors coupled to the memory. The one or more processors are configured to determine a plurality of pre-coders available for uplink transmissions and to select a particular pre-coder from among the plurality of pre-coders. The one or more processors are further configured to initiate encoding of an uplink signal based on the particular pre-coder to generate a pre-coded uplink signal. The pre-coded uplink signal has one or more characteristics that enable a base station to identify the particular pre-coder. The one or more processors are further configured to initiate transmission of the pre-coded uplink signal.

A communication device is provided that includes a baseband circuit and a transmitter configured to transmit a first signal and a projected signal. The baseband circuit is configured to determine the projected signal based on an estimated signal state information such that an energy of a shaped projected signal is smaller than an energy of a shaped signal. The estimated signal state information is an estimate of a signal state information based on the first signal and a received signal that is received by a receiver of the second communication device. The shaped projected signal is the projected signal received by the receiver of the second communication device and filtered by a filter of the second communication device. The shaped signal is the received signal filtered by the filter of the second communication device.

Example channel measurement methods and communications apparatus are described. One example method includes receiving a precoded reference signal by a terminal device, where the precoded reference signal is obtained by precoding a reference signal based on K angle vectors and L delay vectors. First indication information is generated and sent, where the first indication information indicates P weighting coefficients corresponding to P angle-delay pairs. The P weighting coefficients are determined by using the precoded reference signal. The P angle-delay pairs and the P weighting coefficients corresponding to the P angle-delay pairs are used to determine a precoding matrix. Each angle-delay pair includes one of the K angle vectors and one of the L delay vectors. The K angle vectors and the L delay vectors are determined based on uplink channel measurement.