A method of reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, includes: receiving, by the UE and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value n.sub.CQI_ref based on a number of symbols Z′ related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n n−n.sub.CQI_ref in a time domain that is to be used for the aperiodic CSI report; and transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n−n.sub.CQI_ref. The CSI may be calculated by using the most recent A CSI-RS, and thereby the most recent CSI may be reported.

Channel state information (CSI) request procedures are disclosed for use in long term evolution (LTE)/LTE-Advanced (LTE-A) networks with unlicensed spectrum. Instead of relying on periodic reference signals which may not be transmitted because of failed clear channel assessment (CCA) operations, an aperiodic reference signal is defined that provides an on-demand reference signal and CSI request for user equipment (UE), The serving base station transmits an identifier, which signals that the aperiodic reference signal will be transmitted, either in the same subframe or a future subframe, and then transmits the aperiodic reference signal in the designated subframe. UEs served by the base station will receive the identifier, identify a CSI request, either implicitly through the identifier signal received from the base station or explicitly through a UE-specific CSI request, and then generate a CSI report based on the aperiodic reference signal for transmission back to the serving base station.

The present disclosure describes information reporting methods and related apparatuses used to control channel state information reporting between network devices. One example method includes receiving, by a second network device, control information sent by a first network device. The control information can include a trigger signal and a channel state information type, and the trigger signal can be used to trigger the second network device to report target channel state information to the first network device. The second network device determines the target channel state information based on the channel state information type, and then reports the target channel state information to the first network device based on the trigger signal and the channel state information type.

The present disclosure provides a CSI acquisition method. A network side device indicates a CSI feedback configuration group for aperiodic CSI feedback to a UE, and transmits DCI to the UE, the DCI configured to indicate the UE to perform the aperiodic feedback in accordance with an optimum CSI feedback configuration in the CSI feedback configuration group.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may synchronize a beam switch of the base station with transmission of a reference signal for channel state feedback, and schedule a channel state feedback report to be transmitted after the transmission of the reference signal for channel state feedback. Numerous other aspects are provided.

A method of reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, includes: receiving, by the UE and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value n.sub.CQI_ref based on a number of symbols Z′ related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n−n.sub.CQI_ref in a time domain that is to be used for the aperiodic CSI report; and transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n−n.sub.CQI_ref. The CSI may be calculated by using the most recent A CSI-RS, and thereby the most recent CSI may be reported.

A method performed by a User Equipment (UE) is performed. The UE obtains (202) a beam reporting configuration. The beam reporting configuration defines a beam reporting procedure for determining an optimal beam for each of different sub-bands of a system bandwidth. The UE measures (204) different reference signals transmitted by the network node. The measured different reference signals correspond to each of the different sub-bands according to the beam reporting configuration. The UE then determines (206) a preferred beam for each of the different sub-bands based on the corresponding received reference signals.

Disclosed is a method for a terminal reporting channel status information (CSI) to a base station in a wireless communication system. The method comprises receiving, via an upper later, information associated with a single CSI process comprising a firs enhanced multiple input multiple output (eMIMO) type and a second eMIMO type; reporting, to a base station, a first CSI updated on the basis of a first channel status information-reference signal (CSI-RS) corresponding to the first eMIMO type received from a first subframe; and receiving, from the base station, a triggering message of a second CSI calculated on the basis of a second CSI-RS corresponding to the second eMIMO type from a second subframe.

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for group formation and sounding for distributed multi-user multiple input multiple output (MU-MIMO). Some implementations include a method of wireless communication. The method includes transmitting, from a first access point of a plurality of access points, an announcement frame for performing a beamforming procedure for a distributed transmission. The distributed transmission includes a transmission from the plurality of access points. The announcement frame includes at least one identifier of a user terminal in a different basic service set than a basic service set of the first access point. The method further includes transmitting a packet for measuring a channel. The method further includes receiving feedback information from the user terminal based on the packet for measuring the channel. The method further includes transmitting the distributed transmission using the beamforming procedure.

The present disclosure relates to a 5G or pre-5G communication system for supporting a data rate higher than that of a 4G communication system such as an LTE system. The present invention relates to a CSI reporting method and apparatus, and the method of a base station according to the present invention includes transmitting first reference signal information and second reference signal information, transmitting reference signals based on at least one of the first and second reference signal information, transmitting downlink control information (DCI) including information indicating whether the reference signals are transmitted based on the second reference signal information, and receiving Channel State Information (CSI) generated by measuring the reference signals.