Methods, devices and systems are provided for performing for multi-user (MU) transmission. A wireless transmit/receive unit (WTRU) may be configured to receive a frame, decode the received frame and determine whether the received frame is a null data packet (NDP) multi-user (MU) media access control (MAC) physical layer convergence protocol (PLCP) protocol data unit (PPDU) (NDP MU MAC PPDU) based on meeting an NDP condition. The NDP MU MAC PPDU may correspond to an MU transmission and may include a PLCP header which includes an NDP signal (SIG) field having MU control information. Based on the received frame meeting the NDP condition, the WTRU may be further configured to process the NDP SIG field, generate a response based on the NDP SIG field and the MU control information, and transmit the response.

A method for estimating a channel status by a base station in a wireless communication system according to an embodiment of the present invention comprises the steps of: obtaining an uplink channel matrix by using a sounding reference signal (SRS) received from a terminal; transmitting a channel state information-reference signal (CSI-RS) through at least some antenna devices in a two-dimensional antenna array of the base station; receiving a channel quality indicator (CQI) calculated on the basis of the CSI-RS transmission; and obtaining, through a predetermined correction factor obtained on the basis of the CQI and the uplink channel matrix, a downlink channel matrix for the entire two-dimensional antenna array comprising the remaining antenna devices through which the CSI-RS is not transmitted.

This invention presents methods for estimating the uplink SINR and channel estimation error level in MU-MIMO wireless communication systems comprising the BS obtaining the channel coefficients between each receiving antenna of a BS and a transmitting antenna of a UE in the uplink; for the BS estimating the SU-MIMO SINR of a UE using the channel coefficients between a UE and the BS; for the BS estimating the channel estimation error level of a UE using the channel coefficients between a UE and the BS.

Provided is a method for generating inter-cell information for inter-cell interference removal in a wireless communication system. A method by which a terminal removes inter-cell interference comprises the steps of: receiving a signal from a serving cell and a neighboring cell adjacent to the serving cell; identifying the priority of the serving cell for feedback of channel information on the basis of an identifier of the cell and a resource block; identifying whether there is feedback of channel information on the signal received on the basis of the priority; and transmitting the channel information to a base station of the serving cell according to the identification of whether there is feedback.

Provided is a method for generating inter-cell information for inter-cell interference removal in a wireless communication system. A method by which a terminal removes inter-cell interference comprises the steps of: receiving a signal from a serving cell and a neighboring cell adjacent to the serving cell; identifying the priority of the serving cell for feedback of channel information on the basis of an identifier of the cell and a resource block; identifying whether there is feedback of channel information on the signal received on the basis of the priority; and transmitting the channel information to a base station of the serving cell according to the identification of whether there is feedback.

Technique for full-duplex transmission in many-antenna multi-user (MU) multiple-input multiple-output (MIMO) systems is presented in this disclosure. An estimate of a self-interference channel between a plurality of transmit antennas and a plurality of receive antennas is first obtained. A precoder for self-interference reduction is generated based on minimizing a self-interference power related to the self-interference channel that is present at the plurality of receive antennas. Transmission data are modified using the precoder by projecting the transmission data onto a defined number of singular vectors of the self-interference channel that correspond to the defined number of smallest singular values of the self-interference channel. Data are received in full-duplex mode via the plurality of receive antennas simultaneously with transmitting the modified transmission data.

Technique for full-duplex transmission in many-antenna multi-user (MU) multiple-input multiple-output (MIMO) systems is presented in this disclosure. An estimate of a self-interference channel between a plurality of transmit antennas and a plurality of receive antennas is first obtained. A precoder for self-interference reduction is generated based on minimizing a self-interference power related to the self-interference channel that is present at the plurality of receive antennas. Transmission data are modified using the precoder by projecting the transmission data onto a defined number of singular vectors of the self-interference channel that correspond to the defined number of smallest singular values of the self-interference channel. Data are received in full-duplex mode via the plurality of receive antennas simultaneously with transmitting the modified transmission data.

According to one embodiment, a wireless communication device, includes a receiver configured to receive a first field, receive at least one of a plurality of second fields having been multiplexed and transmitted, and decode the one of the second fields to obtain a frame in a case where first information identifying the wireless communication device is not set in the first field, and a controller configured to suppress access to a wireless medium during a period indicated by a value set in the frame.

According to one embodiment, a wireless communication device, includes a receiver configured to receive a first field, receive at least one of a plurality of second fields having been multiplexed and transmitted, and decode the one of the second fields to obtain a frame in a case where first information identifying the wireless communication device is not set in the first field, and a controller configured to suppress access to a wireless medium during a period indicated by a value set in the frame.

Some demonstrative embodiments include devices, systems and/or methods to establish a connection to the Internet via a local gateway (L-GW) function for a LIPA or a SIPTO@LN. The establishment of the connection to the Internet may be performed, for example, by at least one of an E-RAB SETUP procedure, an INITIAL CONTEXT SETUP procedure, an INITIAL UE MESSAGE procedure or an UPLINK NAS TRANSPORT procedure.