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 base station apparatus including a receiving unit to receive, from a terminal, quantized channel state information with respect to a radio channel from a plurality of transmission antennas of the base station apparatus to a plurality of receiving antennas of the terminal. A control unit to determine a control ratio of interference signal to noise with respect to the radio channel based on the channel state information. A precoding matrix computing unit to compute a precoding matrix based on the control ratio of interference signal to noise and a transmission unit to transmit data to one or more of the connected terminals using the precoding matrix.

Abstract: A communication system for supporting a primary user and a secondary user is provided. A base station of a communication system, includes a scheduler to group at least one primary user and at least one secondary user corresponding to each of the at least one primary user according to characteristics of services desired by users, a superposition coding unit to perform superposition coding for primary data associated with the at least one primary user and secondary data associated with the at least one secondary user to generate a transmission data stream, and a beamformer to perform beamforming for the transmission data stream.

Abstract: A method and apparatus for controlling power in a decode-and-forward (DF) relay system is provided. The method of controlling power in a DF relay system includes: acquiring first channel information of a first link between a source node and a destination node, second channel information of a second link between the source node and a relay node, and third channel information of a third link between the relay node and the destination node, by using a pilot signal; determining a power level of the source node from the acquired first through third channel information; and feeding back the determined power level to the source node and the relay node.

Abstract: A transmitter, a receiver, and a method of supporting a space time block code (STBC) scheme in a single carrier (SC) system based on a unique word (UW) are provided. The transmitter supporting an STBC scheme in an SC system based on a UW includes: a space time (ST) encoder encoding a plurality of symbols, which has been received according to a predetermined pattern, using a space time encoding; a first UW adder generating a first transmission sequence by inserting a first UW after a first symbol, from the encoded plurality of symbols; and a second UW adder generating a second transmission sequence by inserting a second UW after a second symbol, from the encoded plurality of symbols.

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 pre-coding method for improving diversity gain in an Orthogonal Frequency Division Multiplexing (OFDM) system and a transmission apparatus and method are disclosed. The transmission method includes converting an input transmission signal into parallel signals, pre-coding the parallel signals with a predetermined frequency offset, performing Inverse Discrete Fourier Transform (IDFT) on the pre-coded signals, and up-converting the IDFT signals and outputting the up-converted signals to a wireless network. By performing pre-coding on a transmission signal with a frequency offset in an OFDM system, diversity gain can be improved.

Abstract: An apparatus and method for transmitting and receiving a data stream in a multi-antenna system, in which a plurality of data streams are received, a plurality of code symbol sequences are generated by precoding the plurality of data streams, the code symbol sequences being mapped to the transmit antennas in a one-to-one correspondence, the code symbol sequences being delayed by delay times for the mapped transmit antennas, and the delayed code symbol sequences are transmitted through the mapped transmit antennas.

Abstract: An explicit outband signaling method for detecting sharable resources for management of public resources in a wireless network supporting Cognitive Radio (CR) technology. To this end, the invention transmits state information for the current channel to a CR system in order to enable communication of the CR users, whose communication with the CR system is impossible due to an influence of an incumbent system, thereby allowing the CR system to stop the use of the interference channel, and to provide a corresponding service with another channel.

Abstract: A resource management method in a Cognitive Radio communication system where at least two Base Stations of heterogeneous networks provide a connection service to Mobile Stations within their service areas is provided. In the method, at least one BS having candidate resources broadcasts its candidate resource information on the downlink of a system information channel. At least one BS lacking in resources searches the downlinks of system information channels from neighbor heterogeneous networks, selects an offer BS among the BSs having candidate resources, and rents resources from the selected offer BS by negotiations.

Abstract: A method of partitioning resources in a CR wireless communication system and a system supporting the same are provided. A new BS receives radio resource status information from a prior BS using a particular frequency band, and requests resource partitioning to the prior BS using a new uplink subchannel defined for communications between BSs. Resource negotiation messages are exchanged over a channel defined between the two BSs so as to efficiently partition resources between the BSs.

Abstract: Dynamic frequency selection based on CR is provided. A CR BS detects an interference-free and unused frequency band. When sensing a new BS that has great signal strength and requires the frequency band during communications in the frequency band, the CR BS releases the frequency band and dynamically selects another frequency band to avoid interference.

Abstract: A communication initialization method at a MAC layer in a CR wireless communication system is provided. The use or non-use of a frequency band is sensed over a broadband with a minimized sensing time in a non-interfering manner with existing communication systems.

Abstract: A current frame containing a multiplicity of current block signals is predicted based on a previous frame by employing an apparatus which produces a predicted current block signal corresponding to each of the current block signals. The apparatus first calculates a correlation factor depicting an improved correlation between the current block signal and a corresponding predicted block signal selected from the previous frame based on an estimation of the motion between the current and the previous frames. Once the correlation factor is computed, the predicted current block signal is determined based on the correlation factor and the current and the predicted block signals.

Abstract: A motion vector detecting method determines a motion vector of a search block included in a search frame of a video signal by using motion vectors of processed neighboring blocks, wherein the search frame is divided into a multiplicity of blocks which include a set of processed blocks whose motion vectors have been determined, and the set of processed blocks contain the processed neighboring blocks which are neighboring blocks of the search block, by: (a) selecting an X-vector and an Y-vector among the motion vectors of the processed neighboring blocks, wherein the X-vector is a vector which is most similar to a horizontal vector the and the Y-vector is a vector which is most similar to a vertical vector, to thereby provide a group of candidate vectors which include the X-vector, the Y-vector and a 0 vector; (b) deciding a candidate motion vector among the group of candidate vectors; and (c) providing the candidate motion vector as the motion vector of the search block in case a distortion between the search

Abstract: A processing block is processed by using an extension-interpolation ("E-I") technique, wherein the processing block consists of N.times.