Abstract: A multiple-input multiple-output (MIMO) communication system and method using a codebook, are provided. A transmitter and at least one receiver included in the MIMO communication system may use at least one codebook from among a plurality of codebooks. Codeword matrices included in one of the codebooks may correspond to vectors included in a block diagonal matrix, and another codebook may be configured by rotating the vectors. The codeword matrices of the remaining codebooks may include the rotated vectors and random vectors.

Abstract: Provided is a feedback method and apparatus in a multiple-input multiple-output (MIMO) communication system. A terminal may determine a preferred pre-coding matrix for a neighboring terminal, based on a reference rank determined by a base station and a preferred pre-coding matrix of the terminal. The terminal may calculate a channel quality indicator (CQI) based on the preferred precoding matrix for the neighboring terminal, and may feed the CQI back to the base station.

Abstract: A method for transmitting and receiving a codebook subset restriction bitmap is provided. The Codebook Subset Restriction (CSR) bitmap transmission method of an evolved Node B (eNB) in transmission mode 9 for communication with 8 antenna ports includes generating a CSR bitmap including bits corresponding to restricted precoding matrix indicators and rank indicators that are not allowed for reporting and transmitting the CSR bitmap to a User Equipment (UE). The CSR bitmap comprises 53 bits corresponding to a first codebook and 56 bits corresponding to a second codebook, the 53 bits corresponding to a first codebook comprise 16, 16, 4, 4, 4, 4, and 1 bits for layers 1, 2, 3, 4, 5, 6, 7, and 8, respectively, and the 56 bits corresponding to a second codebook comprise 16, 16, 16 and 8 bits for layers 1, 2, 3, and 4, respectively.

Abstract: Provided are a method and device for low-complexity feedback in a multiuser and multipoint cooperative communication system. The base station in the multiuser and multipoint cooperative communication system transmits a feedback stop signal to a terminal in order for the terminal receiving the feedback stop signal to stop feedback for a predetermined period. The terminal receiving the feedback stop signal stops the feedback of channel information for a period indicated by the feedback stop signal.

Abstract: A communication system control method, a communication system control apparatus and an apparatus for use in a communication system are provided. The communication system control apparatus includes an information collection unit to collect user set information about candidate user sets grouped by a plurality of base stations, and a scheduler to select target user sets corresponding to the plurality of base stations from among the candidate user sets based on an achievable sum data transmission rate of the plurality of base stations, and perform scheduling with respect to users included in the target user sets, the achievable sum data transmission rate being calculated based on the user set information.

Abstract: Provided is an uplink feedback channel allocation method and apparatus used to feedback data to indicate whether data packets corresponding an enhanced physical downlink control channel (E-PDCCH) were successfully decoded. A terminal may use an additional resource area of an uplink feedback channel or may use an empty resource area of the uplink feedback channel to which feedback information of a data packet corresponding to a physical downlink control channel (PDCCH) is not allocated, to perform feedback.

Abstract: A base station includes a storage unit to store a codebook, wherein the codebook includes a plurality of matrices; a control unit to perform beamforming using the codebook to generate a signal; and a multi-antenna to transmit the signal. For all of the plurality of matrices, all column vectors of a same matrix of the plurality of matrices are orthogonal to each other. For all columns of the plurality of matrices, all column vectors of a same column of all of the plurality of matrices satisfy a Grassmannian line packing (GLP) criterion.

Abstract: A transmitter and a receiver of a multiple input multiple output (MIMO) communication system may use two codebooks to share channel information. When the transmitter uses eight transmit antennas, two codebooks may be defined. When the receiver generates two precoding matrix indicators from two codebooks, a combination of the two precoding matrix indicators may indicate a single precoding matrix. Precoding matrix candidates may also be defined.

Abstract: Provided is a method of generating an adaptive codebook and a multiple input multiple output (MIMO) communication system using the adaptive codebook. A transmitter and a receiver may generate, from a base codebook based on a matrix associated with statistics of a channel matrix, the adaptive codebook maintaining a unitary characteristic. The transmitter may perform scheduling, transmit filter design, and precoding using adaptive codebook based feedback information.

Abstract: Provided is a multiple-input multiple-output (MIMO) communication system that may provide a plurality of feedback modes. A receiver may feed back, to a transmitter, a base codeword indicator indicating one of base codewords included in the base codebook, a differential codeword indicator indicating one of differential codewords included in the differential codebook, and/or a correlation codeword indicator indicating one of correlation codewords included in the correlation codebook. The transmitter may generate a precoding matrix using at least one of the base codeword indicator, the differential codeword indicator, and the correlation codeword indicator.

Abstract: Provided is an uplink feedback channel allocation method and apparatus used to feedback data to indicate whether data packets corresponding an enhanced physical downlink control channel (E-PDCCH) were successfully decoded. A terminal may use an additional resource area of an uplink feedback channel or may use an empty resource area of the uplink feedback channel to which feedback information of a data packet corresponding to a physical downlink control channel (PDCCH) is not allocated, to perform feedback.

Abstract: A transmitter and a receiver of a multiple input multiple output (MIMO) communication system may use two codebooks to share channel information. When the transmitter uses eight transmit antennas, two codebooks may be defined. When the receiver generates two precoding matrix indicators from two codebooks, a combination of the two precoding matrix indicators may indicate a single precoding matrix. Precoding matrix candidates may also be defined.

Abstract: A multiple input multiple output (MIMO) communication system including a base station and at least one terminal may adaptively transform a codebook. The terminal may calculate one or more correlation matrices based on one or more subchannel matrices included in a channel matrix. The terminal may feed back information for the base station to reconstruct the one or more correlation matrices. The terminal may transform a codebook stored in the memory of the terminal, based on the one or more correlation matrices. The base station may verify the one or more correlation matrices using the information for the base station to reconstruct the one or more correlation matrices. The base station may transform a codebook stored in the memory of the base station such that the transformed base station codebook is the same as the transformed terminal codebook.

Abstract: A multiple input multiple output (MIMO) communication method using a codebook is provided. The MIMO communication method may use one or more codebooks and the codebooks may change according to a transmission rank, a channel state of a user terminal, and/or a number of feedback bits. The one or more codebooks may be adaptively updated according to a time correlation coefficient of a channel.

Abstract: Provided are a beamforming vector determining method and an apparatus which may compute a normalization factor of each of a plurality of terminals by normalizing a predetermined reference value using noise power occurring in each of the terminals. A leakage channel of each of the terminals may be estimated, and a beamforming vector for each of the terminals may be determined with respect to a plurality of base stations based on the leakage channel of each of the terminals.

Abstract: The present invention relates to a method and apparatus for interference alignment in a wireless communication system.

Abstract: A terminal and method for generating a codebook for a multiple-input multiple-output (MIMO) system is provided. The codebook generation includes: assigning a single-polarized precoding matrix to diagonal blocks among a plurality of blocks arranged in a block diagonal format in which a number of diagonal blocks corresponds to a number of polarization directions of transmitting antennas; and assigning a zero matrix to remaining blocks excluding the diagonal blocks.

Abstract: A method and apparatus of controlling resources of a femto base station for protecting a macro terminal and controlling interference among femto base stations are provided. The femto base station or a gateway of the femto base station may allocate resource blocks of a femto cell based on a silencing resource block for protecting the macro terminal. Also, the femto base station or the gateway of the femto base station may allocate the resource block of the femto cell based on a relative location between the macro base station and the femto base station and a victim macro terminal. The femto base station or the gateway of the femto base station may allocate the resource block of the femto cell based on a resource block used by a neighboring femto base station.

Abstract: Provided is a control method of a control apparatus for a multi-cell communication system including a plurality of cells, the method including determining a cell edge terminal or an inner cell terminal from each of terminals included in each of the cells, and selecting, from base stations included in the plurality of cells, a first base station and a second base station. The first base station may serve all of a corresponding cell edge terminal and a corresponding inner cell terminal, and the second base station may serve only the corresponding inner cell terminal between the corresponding cell edge terminal and the corresponding inner cell terminal.

Abstract: An adaptive scheduling method and apparatus that adaptively perform scheduling based on a coordinated rank in a multi-cell communication system are provided. A master base station may schedule, with a first priority, master terminals, each of which has a preferred rank equal to a transmission rank of the master base station, and may transmit, to a slave base station, information associated with a group of scheduled master terminals. The slave base station may schedule, with different priorities, slave terminals based on whether a transmission rank of the slave base station is equal to the coordinated rank for the master base station.