Abstract: An apparatus for generating a precoding matrix codebook includes a matrix group generator to generate a first group of unitary matrices based on a vector-based codebook for precoding of a multiple input multiple output (MIMO) communication scheme; a matrix group extender to extend the first group of unitary matrices to generate a second group of unitary matrices; and a matrix group selector to select a group of columns corresponding to a communication rank from each of the unitary matrices that are elements of the second group so that the columns are optimized based on a distance between the columns corresponding to the communication rank.

Abstract: A device and method for generating a codebook. The device includes a generator. The codebook generator is configured to generate a precoding codebook using an 8-PSK alphabet-based 4 bits 4 TX and 8 TX antennas for use in a closed-loop SU-MIMO scheme. According to aspects of the present disclosure, it is possible to generate a precoding codebook for use in 8 Transmission Antenna systems.

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 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 system is provided for performing downlink beamforming based on information fed back by a mobile station. The mobile station includes a channel matrix generation unit to generate a channel matrix with respect to channels ranging from a base station to a mobile station, the base station including multiple transmission antennas, a codebook updating unit to generate a second codebook including a plurality of second codeword matrixes based on the generated channel matrix and a first codebook including a plurality of first codeword matrixes, a codeword selection unit to select at least one transmission codeword matrix from among the plurality of second codeword matrixes, a transmission unit to transmit an index of the selected transmission codeword matrix to the base station, and a receiving unit to receive data transmitted from the base station via the multiple transmission antennas.

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: A communication apparatus and method include: selecting, as a precoding matrix, one of pre-stored at least one matrix Wi, where i is a natural number, and precoding a data stream desired to be transmitted based on the precoding matrix, wherein each diagonal block, among a plurality of blocks included in each of the at least one matrix Wi, includes a nonzero matrix, the nonzero matrix excluding a zero matrix, and wherein each remaining block among the plurality of blocks, excluding the diagonal blocks, includes the zero matrix.

Abstract: A method of generating a codebook for a multiple-input multiple-output (MIMO) system is provided. The codebook generation method 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: 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.

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: An apparatus and method for a communication system including a transmitter and a receiver are provided. The method may include using a first codebook including first codewords and a second codebook including second codewords. The receiver may generate a first precoding matrix indicator corresponding to one of the first codewords and a second precoding matrix indicator corresponding to one of the second codewords. The transmitter may generate a precoding matrix based on the first precoding matrix indicator and the second precoding matrix indicator.

Abstract: A communication apparatus and method include: selecting, as a precoding matrix, one of pre-stored at least one matrix Wi, where i is a natural number, and precoding a data stream desired to be transmitted based on the precoding matrix, wherein each diagonal block, among a plurality of blocks included in each of the at least one matrix Wi, includes a nonzero matrix, the nonzero matrix excluding a zero matrix, and wherein each remaining block among the plurality of blocks, excluding the diagonal blocks, includes the zero matrix.

Abstract: Provided is a coordinated communication method and apparatus that may perform coordinated communication based on long-term channel information, for each sub-band. Base stations may exchange scheduling information of each sub-band with each other to determine a priority among the base stations, and may perform rescheduling for each sub-band based on the determined priority. The base stations may obtain the long-term channel information, and thus may reduce overhead occurring with exchanging of information between a base station and a terminal or between base stations, and may decrease damage due to a delay of channel information associated with a terminal.

Abstract: A communication apparatus includes a mobile terminal to measure a downlink channel state of a downlink between a base station and the mobile terminal, and to determine whether to transmit feedback information about the downlink channel state to the base station based on the measured downlink channel state.

Abstract: A multiple input multiple output (MIMO) communication system and communication method of configuring a codebook are provided. A channel may be formed between a transmitter and a receiver, and a cross-polarization discrimination value (XPD) may be detected. The XPD may vary based on a location of the transmitter and the receiver, a mobility thereof, or a peripheral environment, among other factors. The codebook may be configured based on the XPD.

Abstract: A plurality of reporting modes used to report feedback information is provided. A transmitter and a receiver generate and share feedback information based on a corresponding reporting mode.

Abstract: A multiple input multiple output (MIMO) communication system using a first codebook and a second codebook is provided. The first codebook and the second codebook may independently exist, or may exist in a form of an overall codebook in which the first codebook and the second codebook are integrated with each other. A receiver may extract a first precoding matrix indicator from the first codebook, and may extract a second precoding matrix indicator from the second codebook. The receiver may also extract the first precoding matrix indicator and the second precoding matrix indicator from the overall codebook. The first precoding matrix indicator and the second precoding matrix indicator may be fed back to a transmitter. The transmitter may determine a precoding matrix based on the first precoding matrix indicator and the second precoding matrix indicator.

Abstract: A method of generating a codebook for a multiple-input multiple-output (MIMO) system is provided. The codebook generation method includes: assigning a single-polarized preceding 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 control information transmission and reception method based on a spatial-multiplexing gain, are provided. The control information may be transmitted by obtaining the spatial-multiplexing gain using an E-PDCCH region, and thus, a transmission efficiency of the control information may be improved. The common control information used for decoding the E-PDCCH may be transmitted via a PDCCH, and thus, a base station supporting both a general terminal and an enhanced terminal may effectively transmit the control information. Information associated with an indicator indicating whether the E-PDCCH is to be used during a subsequent resource allocation period may be transmitted, and thus, whether decoding with respect to the E-PDCCH is to be performed during the subsequent allocation period may be determined.