An object of the present disclosure is to provide a beamforming method for a massive MIMO system. Specifically, S routes of data streams to be transmitted via the antenna array are subjected to horizontal direction baseband beamforming processing, to obtain T routes of data streams; the T-routes of data streams are subjected to vertical direction digital beamforming processing to map the T routes of data streams onto a corresponding channel according to a predetermined rule; a data stream on each channel is subjected to analog beamforming processing to map the data stream on each channel onto a corresponding array element of the antenna array for transmission. Compared with the prior art, the present disclosure implements the following advantages: by combining the advantages of RF beamforming with the BB beamforming with limited antennas at the FH, a good flexibility regarding BB algorithm selection and RF beam design is provided, which balances the complexity and performance between BB and RF and implements a massive MIMO in sub-6 GHz.

A communication device for providing a channel state information, CSI, feedback in a wireless communication system includes a transceiver to receive, from a transmitter a radio signal via a time-variant, frequency-selective MIMO channel, the radio signal including downlink reference signals according to a reference signal configuration including a number of antenna ports, and downlink signals including the reference signal configuration; and a processor. The processor estimates an explicit CSI in the frequency domain using measurements on the downlink reference signals on the radio channel, selects a Doppler-delay precoder matrix (W) for a composite Doppler-delay-beam three-stage precoder, calculates either one or more of a channel quality indicator, CQI, and/or a precoder matrix indicator, PMI, and/or a rank indicator, RI, and reports to the transmitter the CSI feedback including either one or more of the CQI, and/or the PMI and/or the RI.

The disclosure provides a method and a device in a User Equipment (UE) and a base station for multi-antenna transmission. The UE transmits a first radio signal in a first time interval, and receives a second radio signal in a second time interval; and then monitors a third radio signal in a third time interval. The first radio signal comprises first information, and the second radio signal comprises second information. Target information is used for a multi-antenna related receiving in the third time interval. A time-domain position of the second time interval is used for determining whether the target information is the first information or the second information. A time-domain position of the third time interval is associated to a time-domain position of the first time interval. The UE can select a beam direction corresponding to a downlink channel according to its measurement, thereby improving efficiency and performances of downlink transmission.

Methods and apparatuses in a wireless communication system. A base station (BS) includes a transceiver and a processor. The processor regulates a transmit power in a direction of an earth station or a predefined receiver by: calculating a power flux density for the BS to the earth station or the predefined receiver; calculating an equivalent antenna gain for other base stations; calculating a directional power back-off level for the other base stations with respect to the earth station or the predefined receiver; generating a restricted precoding matrix indicator based on the calculated directional power back-off level; generating an N1-N2 bitmap for the BS; and applying the N1-N2 bitmap for signal transmission to at least one UE. The N1-N2 bitmap is generated based on: physical parameters of the earth station of the predefined receiver; physical parameters of the BS; an operator input metric; or restricted precoding matrix indicator.

Methods, systems, and devices for wireless communications are described. A base station may associate a first port and a second port each with a set of antenna elements based on a first and a second linear precoding vector, where the phases of the ports are coherent. The base station may generate coefficients indicating a first combination and a second combination of a first data set for a first user equipment (UE) and a second data set for a second UE. In some cases, the base station may apply the first linear precoding vector to the first combination, apply the second linear precoding vector to the second combination, and transmit the first combination using a first transmission beam corresponding to the first port and the second combination using a second transmission beam corresponding to the second port to the first and second UEs.

A method, system and apparatus for beamforming techniques that use approximate channel decomposition are disclosed. According to one aspect, a wireless device is provided. The wireless device includes processing circuitry configured to use a non-constant modulus, NCM, precoder of a NCM codebook to transmit on a physical channel where the NCM codebook is based at least in part on a constant modulus, CM, codebook and a plurality of NCM component matrices, and where the plurality of NCM component matrices are based at least in part on a NCM component matrix mathematical expression, and where an approximate decomposition element-wise product of a CM component matrix mathematical expression and the NCM component matrix mathematical expression corresponds to a channel decomposition matrix.

A method includes: An access point generates an NDPA frame, where the NDPA frame includes a station information field, and the station information field includes an AID subfield indicating an association identifier AID of a station; the station information field further includes a partial bandwidth information subfield; the partial bandwidth information subfield indicates an RU that is in a bandwidth corresponding to the NDPA frame and for which the station needs to feed back channel state information; and the bandwidth corresponding to the NDPA frame is greater than 160 MHz. The access point transmits the NDPA frame.

This application discloses channel sounding methods and communication apparatuses. One method includes: receiving, by a second access point, a user association frame from a first access point, wherein the user association frame carries identification information of a first station and is used to determine a first channel sounding result of the first station associated with the first access point, and determining, by the second access point, the first channel sounding result from a plurality of second channel sounding results based on the user association frame, wherein the plurality of second channel sounding results are obtained by the second access point by performing sounding on a plurality of channel sounding frames from a plurality of stations.

A method for operating a user equipment (UE) comprises receiving information about a channel state information (CSI) report, the information including information about two parameters for basis vectors, N and M; determining n.sub.3.sup.(0) . . . n.sub.3.sup.(M-1), wherein n.sub.3.sup.(0) . . . n.sub.3.sup.(M-1) are indices of M basis vectors selected from N basis vectors; determining nonzero offsets between the index n.sub.3.sup.(0) and indices n.sub.3.sup.(1) . . . n.sub.3.sup.(M-1); and transmitting the CSI report including an indicator i.sub.1,6 indicating the nonzero offsets between n.sub.3.sup.(0)and the indices n.sub.3.sup.(1) . . . n.sub.3.sup.(M-1).

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit an indication of a capability to use a set of beamforming configurations associated with a beamforming circuit architecture of the UE. The UE may receive an indication of a selected beamforming configuration to use for one or more communications. Numerous other aspects are described.