Abstract: An interference alignment method and apparatus in a wireless communication system are provided. A method of a serving Base Station (BS) for uplink interference alignment in a wireless communication system includes estimating a channel for at least one served Mobile Station (MS), estimating an interference channel for at least one neighboring MS, exchanging information about an interference channel with at least one neighboring BS, determining a precoding vector of each of the at least one served MS for configuring interference from all of the at least one neighboring MS as one spatial dimension, and transmitting the determined precoding vector to each of the at least one served MSs.

Abstract: An apparatus and a method for opportunistic user scheduling of two-cell multiple user Multiple Input Multiple Output (MIMO) by a base station, the method comprising: broadcasting signals through random beams to users; and receiving Channel Quality Information (CQI) from best K user set. The CQI is calculated based on all possible combinations of transmit beamforming vectors.

Abstract: An antenna device in a wireless communication includes antenna wires of four sides which include three feeding points and have a loop structure and four main switches which are located among the antenna wires of the four sides, wherein the antenna device operates as a loop antenna when the antenna wires of the four sides are connected according to operations of the main switches and wherein the antenna device operates as dipole antennas when the antenna wires of the four sides are disconnected according to operations of the main switches.

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

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

Abstract: A method and apparatus process interference in a wireless communication system. A method of a master node for interference processing in a wireless communication system includes determining an interference-alignment dimension that is to perform interference alignment, distributing a dimension remaining after determining the interference-alignment dimension, determining a non-interference-alignment dimension not performing the interference alignment, determining at least one matrix for interference alignment of the plurality of transmitters and the plurality of receivers, and transmitting the determined at least one matrix to at least one of the plurality of transmitters and the plurality of receivers.

Abstract: An apparatus and a method for opportunistic user scheduling of two-cell multiple user Multiple Input Multiple Output (MIMO) by a base station, the method comprising: broadcasting signals through random beams to users; and receiving Channel Quality Information (CQI) from best K user set. The CQI is calculated based on all possible combinations of transmit beamforming vectors.

Abstract: An antenna device in a wireless communication includes antenna wires of four sides which include three feeding points and have a loop structure and four main switches which are located among the antenna wires of the four sides, wherein the antenna device operates as a loop antenna when the antenna wires of the four sides are connected according to operations of the main switches and wherein the antenna device operates as dipole antennas when the antenna wires of the four sides are disconnected according to operations of the main switches.

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 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: A method and an apparatus determine an analog beam in a digital/analog hybrid beam-forming system. In a method of a reception end, for determining an analog beam in a hybrid beam-forming system, channel information regarding a transmission end is measured. At least one of an analog transmission beam-forming vector and a reception beam-forming vector is determined depending on the measured channel and a digital beam-forming technique in use. Information of the determined transmission beam-forming vector is fed back to the transmission end.

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 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: 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: 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 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 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: 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: 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.