Abstract: A method and an apparatus for supporting connectivity of Peer-to-Peer (P2P) communication in a mobile communication system are provided. An operating method of a Mobile Station (MS) for providing the connectivity of the P2P communications in the mobile communication system includes connecting P2P communications by searching for a correspondent MS in a first Base Station (BS), determining whether a direct P2P communication is feasible with the correspondent MS in the P2P communications and, when the direct P2P communication is not feasible, setting a P2P relay using the first BS.

Abstract: A method and apparatus for adaptively selecting a Peer-to-Peer (P2P) communication mode in a wireless communication system are provided. In a method of operating a Base Station (BS) for establishing a P2P connection between Mobile Stations (MSs) in the wireless communication system, the method includes, upon receiving a connection request message from a transmitting MS, broadcasting an instruction message to one or more neighbor MSs, receiving P2P-related information from a receiving MS among the neighbor MSs, selecting a communication mode by determining whether P2P communication is possible between MSs according to the P2P-related information and, if P2P communication is possible between the MSs, transmitting a connection response message to the transmitting MS and the receiving MS.

Abstract: A method for supporting a Peer-to-Peer (P2P) communication in a wireless communication system is provided. The method includes identifying whether a Mobile Station (MS) is in a wireless communication active state, a P2P active state, or a P2P previous active state, and transiting to the P2P active state if a P2P connection request occurs in the P2P previous active state and transiting to the P2P previous active state if a P2P communication termination occurs in the P2P active state.

Abstract: A method and apparatus for establishing a Peer-to-Peer (P2P) connection between Mobile Stations (MSs) in a wireless communication system are provided. A method of operating a transmitting MS for establishing the P2P connection between the MSs in the wireless communication system includes when a location of a receiving MS is not known, requesting a Base Station (BS) to transmit a message instructing MSs to prepare for P2P setup, and thereafter, broadcasting to neighbor MSs a message requesting P2P-related information, receiving the P2P-related information from each of the neighbor MSs, generating a list of MSs capable of P2P communication using the received P2P-related information, and establishing a P2P connection by selecting the receiving MS from the list of MSs with which P2P communication is desired. Accordingly, in an environment where the location of the receiving MS is not known, the receiving MS can be found and thus the P2P connection can be established.

Abstract: A multiple-input multiple-output (MIMO) wireless communication system includes a first calculator for calculating pairwise error rates (PERs) for each modulation scheme combination which comprise elements smaller than or equal to receive antennas in number; a second calculator for calculating symbol error rates (SERs) for the each modulation scheme combination using the PERs; a converter for converting the SERs to effective signal to noise ratios (SNRs); and a determiner for determining one among sets of effective SNR per stream acquired from the modulation scheme combinations, as a final effective SNR per stream.

Abstract: An apparatus and method for generating an effective Signal to Noise Ratio (SNR) per stream in a Multiple Input Multiple Output (MIMO) wireless communication system is disclosed. The apparatus includes a selector, a calculator, a generator, and a decider. The selector selects effective streams among whole streams. The calculator calculates a relative SNR rate between the effective streams. The generator generates an equation having as a solution an SNR of a first effective stream. The decider decides an SNR per effective stream using the solution of the equation and the relative SNR rate.

Abstract: An apparatus and a method for interference cancellation in a transmitting end of a multi-antenna system are provided. A precode is generated which maximizes a diversity gain of one or more receive antennas using channel information of the receive antennas to be serviced. Transmit powers of the receive antennas are updated by taking into account a power loss and a shaping loss according to a dirty paper coding. Transmit signals are precoded by updating the precode according to the updated transmit powers. The dirty paper coding is performed on the precoded transmit signals to be transmitted to the receive antennas.

Abstract: A method and system for determining a communication mode in a communication system are provided. The system and method include determining whether a first MS and a second MS are located within a preset area where P2P communications are available, estimating a first expected performance that can be achieved when the first and second MSs operate in a cellular communication mode, estimating a second expected performance that can be achieved when the first and second MSs operate in a P2P communication mode if the first and second MSs are located within the predetermined area, and selecting one of the cellular communication mode and the P2P communication mode as a communication mode between the first and second MSs by comparing the first expected performance with the second expected performance.

Abstract: An apparatus and a method for canceling interference using a space-frequency block coding in a multi-antenna system. The method includes confirming a code for coding to minimize a Pairwise Error Probability (PEP) of a transmit signal of which the PEP is maximized according to a time variation; and coding the transmit signal with the code and transmitting the coded signal via at least two antennas. Accordingly, the interference cancellation can be accomplished while lowering the complexity of the receiver without degrading the spectral efficiency.

Abstract: A mobile communication system includes at least three transmission antennas of first to third transmission antennas, and uses an overlapped antenna scheme for grouping the first and second transmission antennas into a first transmission antenna group and grouping the second and third transmission antennas into a second transmission antenna group. First and second modulators modulate L information bit streams to be transmitted through the first transmission antenna group and output first and second modulation symbol streams. Third and fourth modulators modulate L other information bit streams to be transmitted through the second transmission antenna group and output third and fourth symbol streams. First to fourth puncturers puncture at least one modulation symbol in a predetermined position among the first to fourth modulation symbol streams.

Abstract: A method and apparatus for transmitting common control information by a base station in a wireless communication system are provided. The base station determines whether a first system and a second system different from the first system coexist in a wireless communication system. When the wireless communication system is a coexistence system, the base station indicates information for coexistence of the first system and the second system, position and size information of a resource allocation zone where common control information for the second system can be transmitted, and information necessary for decoding of the resource allocation zone, through a first information element in a downlink subframe where resources are occupied for the first system. The base station transmits the common control information of the second system in the resource allocation zone where the common control information can be transmitted.

Abstract: A method and apparatus for selecting an antenna in a communication system is provided. The apparatus includes a mobile station for determining a set of transmit antennas by considering statistical channel information, for determining a subset of the transmit antennas, which can increase a diversity gain and reduce an effect of a spatial correlation, from among the determined set of the transmit antennas by considering the statistical channel information and instantaneous channel information, for generating antenna selection information by using the determined subset of the transmit antennas, and for feeding back the generated antenna selection information to a base station.

Abstract: An apparatus and method for downlink scheduling in a multi antenna wireless communication system are provided. The apparatus includes a receiver for receiving channel information of at least one mobile station that is selected as an active user by a base station, a judgment unit for judging whether it feeds back its own channel information using the channel information of the selected at least one mobile station, and a transmitter for transmitting the its own channel information to the base station according to judgment of the judgment unit.

Abstract: Disclosed is a method to transmit a signal in a Multiple Input Multiple Output (MIMO) mobile communication system. The method includes determining a Hybrid Automatic Repeat reQuest (HARQ) scheme to be used for a transmission signal; determining a MIMO scheme to be used for the transmission signal in accordance with the determined HARQ scheme; and transmitting the transmission signal using the determined HARQ scheme and the determined MIMO scheme.

Abstract: Disclosed is a symbol synchronization method in an OFDM-based communication system which includes multiple access nodes supporting wireless connection of terminals, supports multi-connection of each terminal for the access nodes and performs synchronization by means of a cyclic prefix. The symbol synchronization method includes monitoring connection of a new access node; setting a number of times by which the new access node transmits equal symbols and a number of times by which at least one existing access node transmits the equal symbols when the connection of the new access node is detected; transmitting the equal symbols by the determined number of times by each access node; and performing synchronization by means of the symbols received from the access nodes by the terminal.

Abstract: An apparatus and method for removing interference in a transmitting end of a multi-antenna system are provided. The method includes receiving channel information for all Receive (Rx) antennas; calculating a beam-forming matrix that maximizes a Signal-to-Interference plus Noise Ratio (SINR) for each Rx antenna by using the received channel information; calculating an integer value which is in proportion to an interference signal for each Rx antenna by using the received channel information and the calculated beam-forming matrix, and performing Dirty Paper Coding (DPC) on a Transmit (Tx) signal by using the calculated integer value; and performing beam-forming by multiplying the Tx signal that has undergone the DPC by the calculated beam-forming matrix. Accordingly, a highest data rate for each user and a highest diversity can be obtained.

Abstract: An apparatus and method for generating an edge sidelobe canceling signal and an uplink communication apparatus using the same in an orthogonal frequency division multiplexing access (OFDMA) system. The uplink communication apparatus includes a transmitting terminal. The transmitting terminal includes a signal mapping unit, a serial-to-parallel conversion unit, an edge sidelobe canceling signal generation unit, an inverse fast Fourier transform (IFFT) unit, and a guard interval insertion and parallel-to-serial conversion unit.

Abstract: An apparatus and method for cooperative transmission in a multi-antenna relay wireless communication system are provided. A receiving end includes an estimator, a reader, a feedback unit and a detector. According to the present invention, the receiving end receives the signal from both the transmitting end and the relay station. Therefore, a reception gain is obtained and a high throughput can be ensured.

Abstract: A method and apparatus for transmitting/receiving a differential space-time block code (STBC) by estimating only channel power in a wireless communication system using a plurality of transmission antennas. A receiver for receiving information symbols encoded by a differential STBC before and decoding the received information symbols collects a signal received at a reception antenna from a plurality of transmission antennas for one block duration; calculates a substitution signal by multiplying the received signal by a signal received for a previous block duration; estimates channel power for a channel from the plurality of transmission antennas to the reception antenna; normalizes the estimated channel power with a normalization value determined as a size of previously received symbols; and calculates information symbols by dividing the substitution signal by the normalized channel power.

Abstract: A collaborative Hybrid Automatic Repeat reQuest (HARQ) in a broadband wireless communication system using a relay station is provided. A transmitting end includes a distance estimator for estimating a distance to a relay station; a controller for determining whether to execute a collaborative HARQ using the estimated distance to the relay station; and a transmitter for, when the execution of the collaborative HARQ is determined and a retransmission request is received from a receiving end, sending a retransmission packet according to a multiple antenna signal processing scheme by constituting a virtual multiple antenna group with the relay station.