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.

Disclosed in the present invention is a method by which a terminal reports channel status information (CSI) to a base station in a wireless communication system. The method comprises the steps of: receiving, through an upper layer, information on one CSI process having a first enhanced multiple input multiple output (eMIMO) type and a second eMIMO type; receiving a first channel status information-reference signal (CSI-RS) corresponding to the first eMIMO type; periodically reporting, to the base station, first CSI measured on the basis of the first CSI-RS; receiving a second CSI-RS, which corresponds to the second eMIMO type, beamformed on the basis of the first CSI; and periodically reporting, to the base station, second CSI measured on the basis of the second CSI-RS, wherein a priority of the first CSI is set to be equal to a priority of a CSI-RS resource indicator (CRI).

Presented systems and methods facilitate efficient and effective communication link adaptation. In one embodiment, a system comprises: a first communication device configured to forward link adaptation information, and a second communication component configured to receive the link adaptation information. The system is part of a wireless local area network (WLAN). The link adaptation information can include Modulation and Coding Scheme (MCS) Feed Back (MFB) related information in a communication frame. The communication frame can include a first field and a second field. The first field indicates the information is being forwarded as unsolicited MFB information or is associated with a solicitation request for the MFB information. The second first field indicates whether the information is MFB information or a request for MFB information.

Methods, apparatuses and systems are provided for transmission of a CSI report. A WTRU may receive an aperiodic CSI reporting request on a PDCCH. The WTRU may determine a time gap between a last symbol of the PDCCH of which the aperiodic CSI reporting request is received and a first uplink symbol of a designated uplink channel for transmission of a corresponding aperiodic CSI report. The determination of the time gap may include consideration of a timing advance value. A determination may be made as to whether a time threshold is shorter than the determined time gap. If the determined time gap is not shorter than the time threshold, the WTRU may transmit the CSI report. If the determined time gap is shorter than the threshold, the WTRU may not transmit the CSI report.

Methods, devices and computer programs for determining new transmit directions to use for beamformed transmissions in case the link quality of an existing direction falters. A transmitting communication device and a receiving communication device cooperate via a beam tracking procedure to determine a new suitable transmit direction to use for upcoming beamformed transmissions. Information relating to the beam tracking procedure is communicated over an existing link that enables communication between the transmitting and receiving communication devices. The receiving communication device provides the transmitting communication device with information about a beam scan performed in order to detect tracking beams transmitted by the transmitting communication device. This information allows the transmitting communication device to determine suitable transmit directions to use.

Methods, systems, and devices for wireless communications are described. In some wireless communications systems, a base station may precode downlink signals to be transmitted to a user equipment (UE) using a precoding matrix. The precoding matrix may be selected by a UE from a number of precoding matrices (e.g., a codebook) and reported to the base station in a channel state information (CSI) report. As described herein, a base station may support techniques for limiting a number of precoding matrices that a UE may evaluate to identify a preferred precoding matrix to be indicated to the base station. In addition, the techniques described herein allow a base station to dynamically indicate an appropriate set of precoding matrices for the UE to evaluate based on the channel conditions at a given time.

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.

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 first 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.

Disclosed in the present invention is a method by which a terminal reports channel status information (CSI) to a base station in a wireless communication system. The method comprises the steps of: receiving, through an upper layer, information on one CSI process having a first enhanced multiple input multiple output (eMIMO) type and a second eMIMO type; receiving a first channel status information-reference signal (CSI-RS) corresponding to the first eMIMO type; periodically reporting, to the base station, first CSI measured on the basis of the first CSI-RS; receiving a second CSI-RS, which corresponds to the second eMIMO type, beamformed on the basis of the first CSI; and periodically reporting, to the base station, second CSI measured on the basis of the second CSI-RS, wherein a priority of the first CSI is set to be equal to a priority of a CSI-RS resource indicator (CRI).

It is provided a method performed by a beamformer device for channel sounding in a network comprising a beamformer device and at least one beamformee device, the method comprises in each round of channel sounding, sending an announcement message including identification information of beamformee devices included in a list when the list is not empty and clearing the list, wherein the beamformee devices included in the list have moved a distance exceeding a threshold value.