Abstract: Provided is an interference aligning method and apparatus that does not perform full feed-forwarding in a hierarchical cell communication. A macro base station may generate respective transmission beamforming vectors of macro terminals to null interference channels to pico terminals and to remove interference among the macro terminals. The effective interference channels are based on reception beamforming vectors of the pico terminals. The macro base station may transmit, to a macro terminal, a feed-forward indicator (FFI) indicating a method of transmitting information associated with a reception beamforming vector of the macro terminal. The macro terminal may obtain information associated with the reception beamforming vector based on the FFI.

Abstract: Provided is a method and system for relaying data using a plurality of relay nodes. The method may include obtaining a first channel matrix related to a first-hop channel and a second channel matrix related to a second-hop channel, generating an effective interference channel matrix based on the first channel matrix and the second channel matrix, and calculating a null space vector of the effective interference channel matrix.

Abstract: Provided is a method and apparatus for distributed transmission power control in a wireless network. The method and apparatus for distributed transmission power control may substantially maximize a minimum value of a transmission rate of each transmitter by controlling a transmission power of each transmitter. The transmission power may be controlled so that transmission rates of transmitters are substantially identical to each other. If the transmission rate is less than a requested transmission rate, the method and apparatus may change a resource of a transmitter that uses a substantially maximum power.

Abstract: A method of assigning and managing reference signals in a multi-cell environment, and a network device and a terminal for applying the method, are provided. Reference signal patterns may be assigned to multiple femtocells through a long term coordination of a central control unit that is used to control multiple cells.

Abstract: Provided are a communication apparatus that may generate a precoding matrix including precoding vectors to cancel or align interference existing in a plurality of terminal devices based on location of the terminal devices, and a terminal device that may estimate a channel formed between the terminal device and the communication apparatus to cancel or align interference signals.

Abstract: A relay and a terminal in a multi-pair two-way network and a communication method thereof is provided. A communication method of a relay of a network including K transmit-and-receive pairs including a plurality of terminals, with the relay including M antennas and each of the terminals including N antennas, including accessing a codebook including codewords, the codebook being configured to enable effective channels from the K transmit-and-receive pairs to the relay to be aligned in independent dimensions, respectively, when the K transmit-and-receive pairs transmit signals simultaneously, each of the effective channels being aligned based on one of the codewords, selecting one or more of the codewords indicating the effective channels from the K transmit-and-receive pairs to the relay, respectively, and transmitting information associated with the selected codewords to corresponding ones of the K transmit-and-receive pairs.

Abstract: A method of assigning and managing reference signals in a multi-cell environment, and a network device and a terminal for applying the method, are provided. Reference signal patterns may be assigned to multiple femtocells through a long term coordination of a central control unit that is used to control multiple cells.

Abstract: A data transmission system that determines data transmission power using a virtual cell is provided. A base station may receive transmission data from a plurality of cooperative base stations positioned around the base station, and model terminals receiving an interference signal from the base station and the plurality of cooperative base stations into a virtual cell. The base station may calculate the influence of the interference signal transmitted to the terminal, using the virtual cell, and determine a transmission power for a plurality of frequency bands based on the interference signal.

Abstract: A method and apparatus for transmitting and receiving content are provided. Content data is multicast from a transmitter to each of receivers. Cooperative receivers among the receivers provide data lost during the multicasting with each other through cooperative reception between the cooperative receivers.

Abstract: Provided is a method and relay that performs network coding. The relay may determine transmission and/or receiving beamforming vectors for terminals so as to align effective channels of a plurality of transmit-and-receive pairs into different dimensions.

Abstract: Provided is a cognitive inter-cell interference control method and apparatus. Inter-cell interference may be measured based on various methods in order to recognize an interference channel, and an appropriate interference control algorithm may be applied to the interference channel by modeling based on overhead. Accordingly, interference may be controlled.

Abstract: A transmitter and/or receiver for performing frequency domain equalization is provided. A transmitter includes a pilot position determination unit for determining positions for inserting pilots in a frequency domain based on frequency spectrums of data, and a pilot insertion unit for inserting the pilots between the frequency spectrums of the data according to the determined positions for inserting the pilots.

Abstract: A communication system performs an uplink communication and a downlink communication using respective radio resources that at least partially overlap each other in both time and frequency, which may cause interference to occur in at least one downlink terminal due to at least one uplink terminal. The at least one uplink terminal and the at least one downlink terminal may process the interference according to a rate split scheme, an interference control scheme, and the like. Interference occurring between at least one transmit antenna and at least one receive antenna of a base station may be processed according to an echo cancellation scheme and the like.

Abstract: Provided is a hierarchical rate splitting method and apparatus in a hierarchical cell communication system. An upper node or a macro base station may adaptively determine a hierarchical splitting mode based on a channel condition of a channel between the macro base station and a macro terminal and/or a performance of pico terminals in comparison to a performance of the macro terminal.

Abstract: Provided is a method of generating a transmit beamforming vector and a receive beamforming vector to substantially eliminate the effect of interference transmitted from macro terminals to a pico base station in a hierarchical cell environment. Also, provided is a method of selecting, from a plurality of macro terminals, a macro terminal for transmitting data to a macro base station.

Abstract: A beamforming method and apparatus for using a rate splitting scheme in a multi-cell multi-antenna system, are provided. The multi-cell multi-antenna system determines transmission and reception beamforming vectors, thereby being divided into a plurality of pairs of single input and single output (SISO) interference channels. A rate splitting scheme may be applied to each of the plurality of pairs.

Abstract: Each of a first transmitter and a second transmitter uses a rate split scheme. Each of the first transmitter and the second transmitter may transmit at least four sub-messages, and different transmission powers may be allocated to the at least four sub-messages. Also, each of receivers may cooperate with each other, may share sub-messages that act as interferences, and may extract desired messages using the shared sub-messages.

Abstract: A method and system of a relay node managing interference in a multi-hop network and a relay node that manages interference is provided. The relay node may determine whether an interference neutralization condition for neutralizing interference among pairs of transmitting nodes and receiving nodes is satisfied, select one of a full interference neutralization and a partial interference neutralization, based on a result of the determination and perform the selected interference neutralization with respect to the pairs of the transmitting nodes and the receiving nodes.

Abstract: A user scheduling and transmission power controlling method in a hierarchical-cell communication system or a multi-cell communication system, and a device to perform the methods, are provided. Interference may occur between various cells in the hierarchical-cell communication system or the multi-cell communication system, and the interference may be controlled by adjusting transmission power of various cells. The various cells may determine an optimal transmission power based on a cost of a corresponding transmission power. Also, the various cells may serve various users and may propose an optimal user scheduling method.

Abstract: A method and apparatus for controlling transmission power in a wireless network area is provided. A target base station may control transmission power in cooperation with a neighboring base station and, thus, a satisfaction with a Quality of Service (QoS) of target terminals may be improved. Additionally, the target base station may determine whether to control the transmission power in cooperation with the neighboring base station, based on a possible improvement in satisfaction with the QoS of the target terminals.