Abstract: A method for efficiently transmitting and receiving control information through a Physical Downlink Control Channel (PDCCH) is provided. When a User Equipment (UE) receives control information through a PDCCH, the received control information is set to be decoded in units of search spaces. Here, the UE monitors a UE-specific search space, among the search spaces. The UE-specific search space is given based on a modulus operation using the variable of Yk for the subframe k and a variable C for the subframe k, wherein Yk is defined by: Yk=(A*Yk?1+B) mod D, the variable C is determined based on the number of CCEs (NCCE) divided by the aggregation level (L), and A, B and D are predetermined constant values predetermined regardless of the aggregation levels (L).

Abstract: The present description relates to a wireless communication system, and more particularly, to a method and apparatus for uplink multiple input multiple output (MIMO) transmission. A method for performing an uplink MIMO transmission according to one embodiment of the present invention comprises the following steps: transmitting, from a first subframe, a first data block and a second data block through a first HARQ process and a second HARQ process, respectively; receiving, at a second subframe, uplink scheduling control information on the first data block and control information which indicates inactivation of the second data block; setting HARQ feedback information on the second data block to an ACK state; and performing retransmission of the first data block from a third subframe on the basis of the uplink scheduling control information on the first data block. Retransmission of the second data block may not be performed until uplink scheduling control information on the second data block is received.

Abstract: A channel coding method of variable length information using block code is disclosed. 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 an inter-row location or an inter-column location of the first matrix was changed. The additional basis sequences satisfy a value 10 of minimum Hamming distance.

Abstract: Provided is a method of receiving a physical layer convergence procedure (PLCP) protocol data unit (PPDU) by an access point (AP) in a wireless local area (LAN) system. The method includes: allocating a first transmission channel bandwidth to a first station (STA) which is multiple input multiple output (MIMO)-paired with the AP; allocating a second transmission channel bandwidth to a second STA which is MIMO-paired with the AP; transmitting to the first STA and the second STA a sync trigger for determining a time point at which the first STA transmits a first PPDU and a time point at which the second STA transmits a second PPDU; and receiving simultaneously the first PPDU and the second PPDU from the first STA and the second STA.

Abstract: There is provided a method and apparatus for transmitting a frame which is performed by a transmission STA in a WLAN system. The method of transmitting a frame includes generating an MAC Protocol Data Unit (MPDU) to be transmitted to a target station, generating a PLCP Protocol Data Unit (PPDU) by attaching a Physical Layer Convergence Procedure (PLCP) header to the MPDU, and transmitting the PPDU to the target station. The PLCP header comprises a partial Association ID (AID) of the target station.

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: The present invention relates to a method and apparatus for acknowledgement (ACK) transmission in a WLAN. A station receives a plurality of data frames from a plurality of other stations and then transmits an ACK for the plurality of data frames to the plurality of stations. The ACK is a multi-user (MU) block ACK frame which includes a plurality of block ACKs for the plurality of stations. One block ACK includes at least one ACK for at least one data frame that is received from one station.

Abstract: A method of allocating a channel in a wireless local area network (WLAN) system is provided. The method includes generating a MAC protocol data unit (MPDU) to be transmitted to a target station (STA), generating a PLCP protocol data unit (PPDU) by attaching a physical layer convergence procedure (PLCP) header to the MPDU, and transmitting the PPDU to the STA, wherein the PLCP header includes channel allocation information for transmission of the PPDU.

Abstract: A method of generating and transmitting a channel quality indicator is disclosed, by which a feedback size of channel quality information is reduced. The present invention includes selecting at least one subband by considering a channel quality of each of entire subbands formed by grouping a predetermined number of subcarriers, additionally selecting subbands adjacent to the at least one subband selected in the first selection step, and generating the channel quality indicator corresponding to the subbands selected in the first selection step and the second selection step.

Abstract: A link adaptation method performed by a station (STA) in a wireless local area network (LAN) system supporting multi-user multiple-input multiple-output (MU-MIMO) is provided. The method includes: receiving a modulation and coding scheme (MCS) request, a steered sounding physical layer convergence procedure (PLOP) protocol data unit (PPDU) which is beam-formed to the STA, and a MIMO indicator including MU-MIMO-related information from an access point (AP); and transmitting feedback information including an MCS acquired from the steered sounding PPDU and the MU-MIMO-related information to the AP in response to the MCS request.

Abstract: A method and apparatus for transmitting control information in a wireless communication system is provided. The method includes transmitting common control information including a multiple input multiple output (MIMO) indicator indicating single user-MIMO (SU-MIMO) or multi user-MIMO (MU-MIMO) to a receiver, generating first precoded dedicated control information by performing precoding on dedicated control information including information for the MU-MIMO by the use of a first precoding matrix, generating second precoded dedicated control information by performing precoding on the first precoded dedicated control information by the use of a second precoding matrix and transmitting the second precoded dedicated control information to the receiver.

Abstract: An interference avoidance method performed by an access point (AP) in a wireless local area network (WLAN) system is provided.

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: 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: A method for efficiently transmitting and receiving control information through a Physical Downlink Control Channel (PDCCH) is provided. When a User Equipment (UE) receives control information through a PDCCH, the received control information is set to be decoded in units of search spaces, each having a specific start position in the specific subframe. Here, a modulo operation according to a predetermined first constant value (D) is performed on an input value to calculate a first result value, and a modulo operation according to a predetermined first variable value (C) corresponding to the number of candidate start positions that can be used as the specific start position is performed on the calculated first result value to calculate a second result value and an index position corresponding to the second result value is used as the specific start position. Transmitting control information in this manner enables a plurality of UEs to efficiently receive PDCCHs without collisions.

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: An STBC based signal transmission method considering the number of symbols within a slot. In transmitting a signal using two or more transmission antennas in a mobile communication system using a structure in which one subframe includes two slots and each slot includes a plurality of symbols, transmission symbols are paired in units of two consecutive symbols within each subframe by an STBC scheme. The transmission symbols are mapped to a frequency region in units of slots and the mapped transmission symbols are transmitted. One symbol within a slot in which the number of symbols excluding symbols for transmitting a reference signal is an odd number is not paired by the STBC scheme.

Abstract: Signal transmitting and decoding methods considering repeatedly transmitted information in transmitting informations in various types are disclosed. Both a first type information varying with a long period and a second type information varying with a short period are simultaneously transmitted by a same period. A receiving side receiving these informations is able to perform fast decoding by unmasking the corresponding information prior to decoding of a next received signal after obtaining the first type information in a manner of considering a fact that the first type information is repeatedly transmitted for a prescribed period of time.

Abstract: A method of transmitting a multiple input multiple output (MIMO) packet by a transmitter in a wireless local area network (WLAN) system is provided. The method includes: generating a MIMO packet including at least one spatial stream set transmitted respectively to at least one receiver, wherein each spatial stream set is encoded on the basis of one of two encoding schemes; transmitting first control information including a MIMO indicator and a first modulation and coding scheme (MCS) field, wherein the MIMO indicator indicates whether the MIMO packet is for single user (SU)-MIMO or multi user (MU)-MIMO, and the first MCS field indicates an MCS used for the MIMO packet if the MIMO packet is for SU-MIMO transmission, and indicates an encoding scheme applied for each of the spatial stream sets if the MIMO packet is for MU-MIMO transmission; and transmitting the MIMO packet to at least one receiver.

Abstract: A method of transmitting a data frame in a wireless local area network is provided. The method includes TXOP the step of: obtaining a transmission opportunity (TXOP) indicating a time interval during which a transmitter has a right to transmit at least one data frame and an available bandwidth for the TXOP and sequentially transmitting a plurality of data frames to at least one receiver during the TXOP, wherein a bandwidth of a subsequent data frame of the plurality of data frames is same to or narrower than a bandwidth of a preceding data frame of the plurality of data frames which is last previously transmitted before the subsequent data frame.