Abstract: According to one embodiment, a method for a wireless local area includes: generating a medium access control (MAC) protocol data unit (MPDU) to be transmitted to a target station; generating a physical layer convergence procedure (PLCP) protocol data unit (PPDU) by attaching a PLCP preamble to the MPDU; selecting a transmission channel; and transmitting the PPDU to the target station over the transmission channel. Selecting the transmission channel includes: performing clear channel assessment (CCA) on a first channel to determine whether the first channel is idle; and only after it is determined that the first channel is idle, selecting the first channel and at least one idle second channel as the transmission channel. The PLCP preamble includes channel allocation information indicating a bandwidth of the transmission channel.

Abstract: A method of link adaptation performed by an access point supporting multi user (MU) multiple input multiple output (MIMO) in wireless local area network system is provided. The method includes transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme (MCS) request (MRQ) and receiving, from the first station, a MCS feedback (MFB) in response to the MRQ, wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

Abstract: A method of transmitting data in a wireless local area network is provided. The method includes the steps of: generating a data unit including a MAC (Medium Access Control) header and MSDU (MAC Service Data Unit), generating an encoded data unit by encoding the data unit, generating one or more spatial blocks by dividing the encoded data unit, dividing each of the one or more spatial block into a first block and a second block, generating a first interleaved block and a second interleaved block by interleaving the first block and the second block respectively, generating a first mapped sequence by mapping the first interleaved block into signal constellation, generating a second mapped sequence by mapping the second interleaved block into signal constellation, generating the transmission signal by performing IDFT (Inverse Discrete Fourier Transform) to the first mapped sequence and the second mapped sequence; and transmitting the transmission signal.

Abstract: A method and apparatus for signal transmission in a Wireless Local Area Network (WLAN) system. The method according to one embodiment includes generating a first very high throughput (VHT) signal, generating a second VHT signal, and transmitting the first VHT signal and the second VHT signal. The first VHT signal includes an indicator indicating that the second VHT signal is to be transmitted by using a single-user multiple input multiple output (SU-MIMO) scheme or a multi-user multiple input multiple output (MU-MIMO) scheme. The first VHT signal and the second VHT signal are used to transmit control information, and the control information includes a modulation and coding scheme (MCS) index indicating an MCS used in the step of transmitting and further includes a spatial stream identifier indicating a number of spatial streams.

Abstract: A method of indicating destination stations, performed by an access point (AP), in a wireless local area network (WLAN) system supporting multi-user multiple input multiple output (MU-MIMO) is provided. The method includes transmitting a sounding request frame to the plurality of destination stations to transmit a sounding frame used for channel estimation between the AP and each destination station, receiving the sounding frame in response to the sounding frame request from each station, and transmitting a first data frame spatially multiplexed with respect to the plurality of destination stations by performing channel estimation on the basis of the sounding frame, wherein the sounding request frame comprises a group identifier (ID) indicating the plurality of destination stations.

Abstract: A method for transmitting data in a wireless local area network, and a device therefore are discussed. The method according to one embodiment includes generating, by a transmitter, a very high throughput (VHT)-SIG-A field; generating, by the transmitter, a VHT-SIG-B field by applying a single column vector; and transmitting, by the transmitter, a physical layer protocol data unit (PPDU) to a receiver, the PPDU including the VHT-SIG-A field and the VHT-SIG-B field. The single column vector is obtained from a number of spatial streams for the receiver.

Abstract: A method of transmitting a data frame by a station in a wireless local area network (WLAN), A station obtains a transmission opportunity (TXOP) for a bandwidth. The TXOP indicates an interval of time during which the station has a right to initiate frame exchange sequences onto a wireless medium. The station selects a transmit bandwidth parameter of a non-initial data unit of a plurality of data units from available bandwidth parameters. The available bandwidth parameters include a first available bandwidth parameter which is same as a transmit bandwidth parameter of a preceding data unit of the plurality of data units and a second available bandwidth parameter which is narrower than a transmit bandwidth parameter of the preceding data unit. The station transmits, during the TXOP, the non-initial data unit according to the transmit bandwidth parameter of the non-initial data unit.

Abstract: A method for transmitting a reference signal for channel measurement (CSI-RS) to a user equipment; a base station therefore; a method for receiving a CSI-RS; and the user equipment therefore are discussed. The method for transmitting a CSI-RS according to one embodiment includes transmitting CSI-RS pattern information for indicating a pattern of time-frequency resource to be nulled, hereinafter referred to as null CSI-RS pattern, and CSI-RS subframe information for indicating in which subframe the null CSI-RS pattern occurs; and nulling a time-frequency resource corresponding to the null CSI-RS pattern in a subframe corresponding to the CSI-RS subframe information, hereinafter referred to as null CSI-RS subframe, based on the CSI-RS pattern information and the CSI-RS subframe information. The CSI-RS subframe information includes information indicating a periodic interval with which the null CSI-RS subframe occurs. The periodic interval corresponds to a plurality of subframes.

Abstract: A method for transmitting and receiving uplink signals using an optimized rank 3 codebook is disclosed. The optimized rank 3 codebook includes 6 precoding matrix groups, each of which has 1 variable having an amplitude of 1. Preferably, the optimized 4Tx rank 3 codebook has 12 precoding matrix, two precoding matrixes are selected from each the above 6 precoding matrix groups considering chordal distance and the number of precoding matrix.

Abstract: Disclosed is a method for allowing a station to transmit a sounding signal in a multiple-antenna wireless communication system, the method including receiving a group defining information about a group to which the station belongs from an access point (AP); determining a transmission time taken in transmitting a sounding signal by the respective stations, which belong to the group, on the basis of the group defining information; and transmitting a sounding signal to the AP in accordance with the transmission time and preset transmission order when receiving a sounding request signal from the AP.

Abstract: According to one embodiment, a method for a wireless local area includes: generating a medium access control (MAC) protocol data unit (MPDU) to be transmitted to a target station; generating a physical layer convergence procedure (PLCP) protocol data unit (PPDU) by attaching a PLCP preamble to the MPDU; selecting a transmission channel; and transmitting the PPDU to the target station over the transmission channel. Selecting the transmission channel includes: performing clear channel assessment (CCA) on a first channel to determine whether the first channel is idle; and only after it is determined that the first channel is idle, selecting the first channel and at least one idle second channel as the transmission channel. The PLCP preamble includes channel allocation information indicating a bandwidth of the transmission channel.

Abstract: A method of link adaptation performed by an access point supporting multi user(MU) multiple input multiple output(MIMO) in wireless local area network system is provided. The method includes transmitting, to a first station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU) containing a modulation and coding scheme(MCS) request(MRQ) and receiving, from the first station, a MCS feedback(MFB) in response to the MRQ, wherein the first station is one of destination stations of MU-MIMO transmission performed by the access point, and the MFB includes a recommended MCS value computed, by the first station, on the assumption that the first station, as a member of the destination stations, receives data transmitted over at least one spatial stream allocated to the first station in MU-MIMO transmission.

Abstract: A method for a channel sounding in a wireless local area network. A station receives a 20 MHz null data packet announcement (NDPA) frame and at least one duplicate 20 MHz NDPA frame. The at least one duplicate 20 MHz NDPA frame is a duplicate of the 20 MHz NDPA frame. The station also receives a null data packet (NDP) following the 20 MHz NDPA frame and the at least one duplicate 20 MHz NDPA frame. The bandwidth over which the 20 MHz NDPA frame and the at least one duplicate 20 MHz NDPA frame are transmitted is the same as a bandwidth over which the NDP is transmitted. The station transmits a report frame for the channel sounding. The 20 MHz NDPA frame and the at least one duplicate 20 MHz NDPA frame comprise bandwidth information indicating the bandwidth over which the frames are transmitted.

Abstract: A method and terminal are described for allocating resources for transmitting a signal in a multiple-input multiple-output (MIMO) wireless communication system. An uplink signal is transmitted using L layers at a terminal in a multiple-input multiple-output (MIMO) wireless communication system. Modulation symbols are generated by modulating output bit sequences of an interleaver matrix by a unit of log2Q bits, where Q is a modulation order. Each of the output bit sequences has a size of L·log2Q bits. The modulation symbols are mapped to the L layers and transmitted by using the L layers. The output bit sequences are generated by reading out entries of the interleaver matrix, column by column.

Abstract: A method and a device for reporting a modulation and coding scheme (MCS) feedback in a wireless local area network are provided. A responding station receives, from a requesting station, a requesting Physical layer Protocol Data Unit (PPDU) for requesting a MCS feedback via a plurality of spatial streams. A recommended MCS is estimated under an assumption that the requesting station will transmit at least one first spatial stream among the plurality of spatial streams used for the requesting PPDU, The responding station transmits, to the requesting station, the MCS feedback including a recommended MCS field indicating the recommended MCS and a recommended stream field indicating a number of at least one recommended spatial stream. A number of the at least one first spatial stream used for estimating the recommended MCS is equal to the number of the at least one recommended spatial stream.

Abstract: A method and apparatus for allowing a UE to transmit uplink signals using a MIMO scheme are disclosed. In order to maintain good Peak power to Average Power Ratio (PAPR) or Cubic Metric (CM) properties when the UE transmits uplink signals using the MIMO scheme, the UE uses a precoding scheme based on a precoding matrix established in a manner that one layer is transmitted to each antenna in specific rank transmission.

Abstract: A method and apparatus for allowing a UE to transmit uplink signals using a MIMO scheme are disclosed. In order to maintain good Peak power to Average Power Ratio (PAPR) or Cubic Metric (CM) properties when the UE transmits uplink signals using the MIMO scheme, the UE uses a precoding scheme based on a precoding matrix established in a manner that one layer is transmitted to each antenna in specific rank transmission.

Abstract: A method of transmitting a Physical Layer Convergence Procedure (PLCP) frame in a Very High Throughput (VHT) Wireless Local Area Network (WLAN) system includes generating a MAC Protocol Data Unit (MPDU) to be transmitted to a destination station (STA), generating a PLCP Protocol Data Unit (PPDU) by adding a PLCP header, including an L-SIG field containing control information for a legacy STA and a VHT-SIG field containing control information for a VHT STA, to the MPDU, and transmitting the PPDU to the destination STA. A constellation applied to some of Orthogonal Frequency Division Multiplex (OFDM) symbols of the VHT-SIG field is obtained by rotating a constellation applied to an OFDM symbol of the L-SIG field.

Abstract: A method of transmitting information on a modulation and coding scheme (MCS) in a wireless local area network system is provided. A responding station receives a physical layer protocol data unit (PPDU) from a requesting station, configures a MCS feedback (MFB) based on the PPDU, and transmits feedback information to the requesting station. If the MFB is configured as a response to a MFB request (MRQ) of the requesting station, the feedback information includes the configured MFB and a MFB type field indicating that the MFB is configured as a response to the MRQ of the requesting station. If the MFB is not configured as a response to the MRQ of the requesting station, the feedback information includes the configured MFB, a MFB type field indicating that the MFB is not configured as a response to the MRQ of the requesting station, and coding information indicating a PPDU coding type.

Abstract: A method of transmitting data in a wireless local area network; and a device therefore are discussed. The method according to one embodiment includes generating, by a transmitting station, a physical layer convergence procedure (PLCP) protocol data unit (PPDU), the PPDU including a signal field and a data field; and transmitting, by the transmitting station, the PPDU to the receiving station. The signal field includes a class type indicating whether a transmission type of the PPDU is an uplink transmission or a downlink transmission.