Abstract: A method of transmitting a frame in a Wireless Local Area Network (WLAN) system is provided. The method includes receiving, by a first station, information about an association identifier (AID) from an access point, the AID identifying the first station in the WLAN system; transmitting, by the first station, a Direct Link Setup (DLS) request frame to a second station to request a setup for a direct link with the second station, the DLS request frame including the AID of the first station; receiving, by the first station, a DLS response frame from the second station in response to the DLS request frame, the DLS response frame including an AID of the second station; and transmitting, by the first station, a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) to the second station or the access point.

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 transmitting a training signal in a Wireless Local Area Network (WLAN) system includes generating one or more first training signals for a first destination station and one or more second training signals for a second destination station by applying a mapping matrix P to a training signal generation sequence, mapping the first training signals and the second training signals to a plurality of antennas according to an antenna mapping matrix, and performing Inverse Fast Fourier Transform (IFFT) on each of the first training signals and the second training signals mapped to the plurality of antennas and transmitting the training signals through the plurality of antennas.

Abstract: A method and device for communicating in a wireless local area network are discussed. The method can include selecting, by a transmitting station, a transmission channel by performing a Clear Channel Assessment (CCA) and transmitting, by the transmitting station, a Physical layer Protocol Data Unit (PPDU) over the selected transmission channel to a receiving station, wherein the transmission channel includes a primary 20 MHz channel and a secondary 20 MHz channel if the secondary 20 MHz channel was idle, and wherein the transmission channel includes the primary 20 MHz channel, the secondary 20 MHz channel and a secondary 40 MHz channel if both the secondary 20 MHz channel and the secondary 40 MHz channel were idle.

Abstract: A method and device for receiving a data block in a wireless communication system, the method performed by a receiver. The method includes: receiving a physical layer protocol data unit (PPDU) from a transmitter over an operating channel, the PPDU including a signal field, a Very High Throughput-Signal-A (VHT-SIG-A) field, a Very High Throughput-Signal-B (VHT-SIG-B) field and a padded data block, generating a first data block by removing zero or more physical padding bits from the padded data block in a physical layer; and generating a second data block by removing zero or more Medium Access Control (MAC) padding bits from the first data block in a MAC layer.

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 for channel-coding information bits using a code generation matrix including 32 rows and A columns corresponding to length of the information bits includes, channel-coding the information bits having “A” length using basis sequences having 32-bit length corresponding to columns of the code generation matrix, and outputting the channel-coded result as an output sequence. If “A” is higher than 10, the code generation matrix is generated when (A-10) additional basis sequences were added as column-directional sequences to a first or second matrix. The first matrix is a TFCI code generation matrix composed of 32 rows and 10 columns used for TFCI coding. The second matrix is made when at least one of an inter-row location or an inter-column location of the first matrix was changed. The additional basis sequences satisfy a value 10 of a minimum Hamming distance.

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: Methods and devices for transmitting or receiving data in a wireless local area network are provided. The method in one embodiment includes transmitting, by a transmitter, a first long training field (LTF) to a receiver; transmitting, by the transmitter, a very high throughput (VHT)-SIG-A field to the receiver; transmitting, by the transmitter, a second LTF for multiple input multiple output (MIMO) channel estimation to the receiver; transmitting, by the transmitter, a VHT-SIG-B field to the receiver; and transmitting, by the transmitter, a data field to the receiver, wherein the first LTF, the VHT-SIG-A field, the second LTF, the VHT-SIG-B field and the data field are sequentially transmitted, and wherein the second LTF and the data field are mapped to at least one spatial stream based on a mapping matrix but the first LTF and the VHT SIG-A field are not mapped to the at least one spatial stream.

Abstract: An interference avoidance method performed by an Access Point (AP) in a WLAN system in an Overlapping Basic Service Set (OBSS) environment is provided. The interference avoidance method includes receiving an interference avoidance request message from the first STA, the interference avoidance request message informing that frame transmission of the AP acts as interference with a first STA; transmitting an interference avoidance response message in response to the interference avoidance request message; obtaining first channel information about a first channel between the first STA and the AP from the first STA which has received the interference avoidance response message; determining a transmitting steering matrix based on the first channel information; and transmitting data to a second STA by performing beamforming according to the transmitting steering matrix.

Abstract: There is provided a method of transmitting control information in a Wireless Local Area Network (WLAN) system, comprising transmitting first control information by means of cyclic shift delay diversity beam-forming and transmitting second control information. The first control information comprises information necessary for each of a plurality of target stations of the second control information to receive the second control information. The second control information beamformed and transmitted to the plurality of target stations.

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 control information in a wireless communication system is disclosed. A method of receiving control information in a mobile station which receives downlink data from a plurality of cells simultaneously in a wireless communication system comprises receiving downlink control information including the control information on data transmitted from the plurality of cells from a serving base station via a downlink control channel.

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 communication method in a wireless local area network (WLAN) system is provided. The communication method includes: communicating, by a first station, with a second station, via an operating channel of the new BSS, a width of the operating channel being equal to one among 40 MHz, 80 MHz, 80+80 MHz and 160 MHz. The operating channel includes a primary channel selected among a set of channels by the second station, the selected primary channel is not identical to a secondary 20 MHz channel of one or more existing BSSs scanned by the second station, and the secondary 20 MHz of the one or more existing BSSs is contiguous with a primary 20 MHz channel of the one or more existing BSSs.

Abstract: There is provided a method of transmitting control information in a Wireless Local Area Network (WLAN) system, comprising transmitting first control information by means of cyclic shift delay diversity beam-forming and transmitting second control information. The first control information comprises information necessary for each of a plurality of target stations of the second control information to receive the second control information. The second control information beamformed and transmitted to the plurality of target stations.

Abstract: A method of transmitting a training signal in a Wireless Local Area Network (WLAN) system includes generating one or more first training signals for a first destination station and one or more second training signals for a second destination station by applying a mapping matrix P to a training signal generation sequence, mapping the first training signals and the second training signals to a plurality of antennas according to an antenna mapping matrix, and performing Inverse Fast Fourier Transform (IFFT) on each of the first training signals and the second training signals mapped to the plurality of antennas and transmitting the training signals through the plurality of antennas.

Abstract: A method for performing retransmission at a user equipment of a MIMO wireless communication system is disclosed. The method comprises transmitting multiple transport blocks to a base station for a transmission unit time in accordance with uplink grant information, which includes a first new data indicator; receiving ACK/NACK (Acknowledgement/Negative-ACK) responses corresponding to the respective transport blocks and uplink grant information, which includes a second new data indicator, from the base station; and performing new transmission or retransmission for the multiple transport blocks in one transport block unit for a transmission unit time in accordance with the ACK/NACK responses and the second new data indicator, if transport rank is reduced to 1.

Abstract: A method and a station are described for transmitting a data frame in a wireless local area network (WLAN). The station obtains a transmission opportunity (TXOP) and transmits, during the TXOP, a preceding data unit of a plurality of data units comprising a control field indicating a selected bandwidth for the preceding data unit. The station selects a transmit bandwidth parameter of a non-initial data unit of the 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 the 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, which comprises a control field indicating a selected bandwidth for the non-initial data unit.

Abstract: A method for transmitting a control signal, performed by a wireless device. The method according to one embodiment includes allocating resource elements (REs) for a control channel; and transmitting the control signal through the Res. Each RE in the REs for the control channel is associated with one out of two antenna ports. The two antenna ports are included in a plurality of antenna ports used for transmitting demodulation reference signals (DM RS).