Abstract: A method of determining an optimal transmission mode and a data frame structure for determining an optimal transmission mode in a data transmission system using a relay, are provided. Any one of a base station, a relay, and a mobile station determines an optimal transmission mode from among a plurality of transmission modes, and the base station transmits the determined optimal transmission mode by enabling the determined optimal transmission mode to be included in the system information duration of the data frame, so that the overall relay system can transmit data according to the optimal transmission mode.

Abstract: A method and apparatus for transmitting and receiving a signal in a wireless communication system. The wireless communication system includes a transmitter with at least four transmit antennas and a receiver with at least one receive antenna. Space Frequency Block Coding (SFBC) processes are performed for input signals on a basis of two antenna pairs. Signal blocks whose number corresponds to the number of transmit antennas are output. A Space Time Block Coding (STBC) process is performed for the signal blocks generated according to the antenna pairs. Signals carried by single carriers are transmitted through the at least four transmit antennas mapped to the signal blocks.

Abstract: Provided is a method of an angle of arrival (AoA) estimating apparatus. The AoA estimating apparatus may obtain at least two candidate values for an AoA of a received signal, based on a first steering vector. The AoA estimating apparatus may further detect a second steering vector corresponding to a predetermined rotation angle to which the AoA estimating apparatus rotates, and may determine the AoA based on one of the at least two candidate values, with respect to the second steering vector and the predetermined rotation angle.

Abstract: Provided is a block Time Domain Equalizer (TDE) for a Time Reversal-Space Time Block Codes (TR-STBC) system. The block TDE comprises a block equalizer which generates an output based on an equalizer tap weight with respect to two consecutively received blocks, an equalizer tap weight updating unit which generates an error vector based on the output and the equalizer tap weight and updates the equalizer tap weight using the error vector, and a signal processing unit which processes the output into a digital signal wherein zero padding is eliminated from the output.

Abstract: Provided is a communication system using a space division multi-user multiple input multiple output (SD-MIMO) communication method. A transmission apparatus may transmit, to each of terminals included within a coverage, common control information commonly transmitted to the terminals and individual control information individually transmitted to each of the terminals. The transmission apparatus does not precode the common control information and transmits the non-precoded common control information. The transmission apparatus precodes the individual control information and transmits the precoded individual control information.

Abstract: A method of controlling data transmission mode in an orthogonal frequency division multiple access (OFDMA) wireless relay system and an apparatus using the method are provided. The method of controlling data transmission mode includes: dividing all frequency bands of an OFDM signal into a frequency band group including at least one subcarrier band; estimating a plurality of channels of wireless links which respectively link a base station (BS), at least one relay station (RS), and a mobile station (MS) with respect to the at least one subcarrier band; selecting any one of a plurality of data transmission modes based on a feature of the estimated plurality of channels of wireless links with respect to the frequency band group; and applying the selected data transmission mode to all of the at least one subcarrier bands in the frequency band group to transmit data.

Abstract: Disclosed are a data receiving apparatus that may discriminate a type of a received data frame, and a data transmission apparatus that may apply a constellation mapping scheme to a data frame so that a data receiving apparatus may discriminate the data frame in accordance with the constellation mapping scheme applied to the data frame.

Abstract: A method and apparatus for transmitting data in a communication system. In the apparatus, a repeater repeatedly processes an input signal a predetermined number of times. A Space-Frequency Block-Coded (SFBC) encoder performs SFBC coding on the repeatedly processed input signals, and outputs at least two signal blocks in parallel. A cyclic prefix (CP) inserter inserts a CP in the signal blocks and transmits the CP-inserted signal blocks via associated transmission antennas using a single carrier.

Abstract: A wireless data transmission method and apparatus are provided for compensating a distortion due to a clipped amplitude when an amplitude of a signal is clipped to reduce a peak to average power ratio (PAPR) in a wireless communication system using an orthogonal frequency division multiplexing (OFDM) scheme and a transmit diversity method using an orthogonal coding. The wireless data transmission apparatus includes a coding unit which Space-Time block codes a first data stream into a plurality of second data streams, the plurality of second data streams being orthogonal to each other; an inverse Fourier transform unit which performs an inverse Fourier transform of each of the Space-Time block coded second data stream and generates a plurality of time domain signals; and a plurality of amplitude clipping units which clips an amplitude of each of the plurality of generated time domain signals.

Abstract: An apparatus and a method for commonly applying channel scanning to non-network scanning schemes in a digital video broadcasting system are provided. The method includes deleting all services stored in a database, temporarily storing services scanned through each frequency in a temporary storage unit, and performing channel scanning for all frequencies. Accordingly, the same service including different Logical Channel Numbers (LCNs) that is repeatedly stored or another service including the same LCN that is not stored in a Multi Frequency Network (MFN) boundary area using the non-networking scanning scheme is prevented.

Abstract: A communication device and a mobile station to perform interference alignment, and an interference alignment method are provided. Interference alignment may be performed to enable an interference signal, received in a mobile station, to be removed using channel information fed back from the mobile station.

Abstract: A method of assigning a carrier for mitigating inter-cell interference in a fixed relay based communication system is provided. In a normal mode, the method includes defining at least one sector group by grouping cells at least two tiers away from each other; selecting a single sector group; and assigning, by a base station of the selected sector group, a first carrier to a relay station or a mobile station which is located in a coverage area of the base station. In a relay mode, the method includes determining whether a current mode is a normal mode or a relay mode; determining whether a base station is included in a selected sector group; and assigning carriers to a relay station or a mobile station belonging to the base station, when the current mode is the normal mode and the base station is included in the selected sector group.

Abstract: A method and apparatus for controlling a power of a relay are provided. The apparatus includes: a signal receiver which receives signals which are transmitted to a plurality of receiving antennas directly from a source or via at least one relay; a channel information acquirement unit which acquires channel information between the source and the at least one relay, and acquires channel information between the at least one relay and the plurality of receiving antennas; a power control signal generation unit which generates a power control signal, based on the acquired channel information and a maximum SNR; and a relay power control unit which transmits the generated power control signal to the relay and thereby controls a transmit signal power with respect to the at least one relay.

Abstract: A receiver for ICI cancellation in a MIMO system is provided, in which a detection orderer determines a subcarrier detection order according to SINRs of subcarriers in an I-CMOS, a detector receives a vector on the subcarriers and a priori information from a decoder according to the subcarrier detection order and iteratively estimates the received vector using the a priori information, and the decoder decodes an ICI-cancelled signal according to the estimate.

Abstract: A cellular communication system and method supporting both a time division duplexing (TDD) scheme and a frequency division duplexing (FDD) scheme. The apparatus includes a plurality of mobile stations, at least three first fixed stations communicate with the mobile station based on the FDD scheme, the first fixed station defining respective macro cells that are contiguous and form a virtual cell, and a cluster including at least one second fixed station communicating with the mobile stations based on the TDD scheme, the second fixed station defining a micro cell in the virtual cell.

Abstract: A fast adaptive time domain equalizer for a Time Reversal-Space Time Block Code (TR-STBC) system is provided. More particularly, a reduced-complexity hybrid Decision Feedback Equalizer (DFE) configuration for the TR-STBC system, and a Least Mean Square (LMS), a normalized LMS (NLMS), and a Recursive Least Square (RLS)-based adaptive algorithms for the hybrid DFE are provided.

Abstract: Disclosed is a cellular-based wireless communication system, and more particularly a method for allocating resources for data transmission in a cellular-based wireless communication system employing a multicarrier scheme. Frequency resources are divided into time slots defined by one frame and the divided time slots are allocated to an uplink and the downlink. During a predetermined time period, the frequency resources are allocated as resources for transmitting sync preambles. During a next predetermined time period, the frequency resources are allocated in such a manner that the frequency resources for sectors are successively and repeatedly used as resources for transmitting broadcasting messages on a sector-by-sector basis. In the remaining time slots, except the time slots for transmitting the preambles and the broadcasting messages, the frequency resources are allocated as resources for transmitting channel estimation midambles for dynamic channel allocation.

Abstract: A communication system may include a serving base station and neighboring base stations. Each of the serving base station and the neighboring base stations may have a corresponding user group. Terminals belonging to a particular user group may feed back information associated with interference channels, and reasonably generate a precoding matrix. Through this, it is possible to perform an accurate interference alignment and to enhance a throughput. In this instance, terminals belonging to the other user groups may feed back information associated with a throughput, and a corresponding base station may perform the interference alignment using a user selection resulting in decreased overhead.

Abstract: Provided is a signal transmission system including a terminal to receive a signal using an interference alignment scheme, and a transmitting base station to transmit, to the terminal, a signal where interference is aligned. The transmitting base station may select, from a plurality of terminals, a target terminal to receive the signal using the interference alignment scheme. The selected target terminal may receive the signal from the transmitting base station and receive interference signals from a plurality of interference base stations.

Abstract: A communication network applying an interference alignment scheme with a low or reduced complexity is provided. The communication network may include a plurality of transmit nodes and a plurality of receive nodes. A plurality of combinations of transmit-receive pairs may exist between the plurality of transmit nodes and the plurality of receive nodes. A communication apparatus for the communication network may select, from candidate combinations of transmit-receive pairs, a target combination to be applied with the interference alignment scheme. In particular, the communication apparatus may sequentially decrease a number of candidate combinations to select the target combination with a low complexity.