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: A method and apparatus for allocating frequency resources for peer to peer (P2P) communication between terminals without a base station are provided. The method determines resources used for a direct communication between two terminals in a communication system. The method includes determining uplink frequency resources of a cellular communication system for use in the direct communication between the two terminals, determining a primary maximum transmission power to minimize interference caused by the direct communication on the cellular communication system and performing the direct communication between the two terminals by using the uplink frequency resources and a transmission power less than the determined primary maximum transmission power.

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 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: An apparatus and method for supporting Peer-to-Peer (P2P) communications in a broadband wireless communication system are provided. A frame used by the terminal in P2P communications includes a plurality of P2P contention channels overlapping with a region for cellular communications and at least one P2P dedicated channel allocated by a base station only for the P2P communications. The method includes establishing a P2P connection with a correspondent terminal through the at least one P2P dedicated channel, and exchanging P2P communication data with the correspondent terminal through at least one of the plurality of P2P contention channels.

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: An apparatus and method for performing Peer-to-Peer (P2P) communication in a broadband wireless communication system are provided. The apparatus includes a first calculator for calculating a maximum Transmit (Tx) power level for each band of a Mobile Station (MS) by using channel information and capability information of the MS; a second calculator for calculating a preference for each band of the MS by using information on the maximum Transmit (Tx) power level for each band and by using interference information for each band of a counterpart MS; and a selector for selecting a P2P transmission band of the MS according to the preference for each band.

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: Disclosed is a data transmission/reception method and system for minimizing intercarrier interference (ICI) in a communication system using a multicarrier. The data transmission method by a transmitter includes grouping transmission signals in units of a predetermined number of transmission signals when the transmitter has received the transmission signals, multiplying each group of the transmission signals by a transmission coding matrix, and transmitting the transmission signals multiplied by the transmission coding matrix to a receiver.

Abstract: A method and apparatus for scheduling multiuser terminals in a communication system is provided. A receiver receives feedback information from a plurality of user terminals. A user grouping unit selects terminals having a maximum Signal to Interference plus Noise Ratio (SINR) among terminals having the same beam index and beam subset index, from among the plurality of user terminals, and generates terminal groups using the selected terminals, each terminal group including terminals having the same beam subset index. A group scheduling unit calculates a throughput of each of the terminal groups to determine which terminal group has the maximum throughput. A random precoding unit generates random beam vectors corresponding to terminals included in the terminal group determined to have the maximum throughput, and transmits data for user terminals, included in the terminal group determined to have the maximum throughput, over the generated random beam vectors.

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: A retransmission apparatus and method in a wireless communication system are provided, in which it is determined whether a retransmission signal exists, when channels for transmitting signals are changed to new channels, a channel is allocated to the retransmission signal, taking into account state information about the new channels, when the retransmission signal exists, and the retransmission signal is transmitted on the allocated channel.

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: Disclosed is an apparatus and a method for signal transmission and reception according to a pre-processing scheme in a MIMO mobile communication system. The method includes: inputting a symbol; and pre-processing the input symbol according to a pre-processing matrix corresponding to pre-processing matrix information and transmitting the pre-processed symbol through a corresponding transmission antenna, wherein the pre-processing matrix is determined in accordance with a number of transmission antennas and a rate used in the MIMO mobile communication system.

Abstract: Selection of a relay station in a broadband wireless communication system is provided. In the broadband wireless communication system, a Base Station (BS) includes a sorter for generating a first index group in which indices of relay stations are sorted according to channel information between the BS and each relay station; a receiver for receiving a second index group in which the indices of the relay stations are sorted according to channel information between a Mobile Station (MS) and each relay station; and a selector for selecting a relay station to be used to communicate with the MS by using the first index group and the second index group.

Abstract: An apparatus and method for scheduling a multiuser and a single user in a Multiple Input Multiple Output (MIMO) system are provided. The method for scheduling a multiuser and a single user at BS in MIMO system includes determining ratios of MultiUser-MIMO (MU-MIMO) chunks and Single User-MIMO (SU-MIMO) chunks to allocation chunks, determining the MU-MIMO chunks in the determined ratio and the remaining chunks as the SU-MIMO chunks, transmitting chunk information relating to the determined chunks to one or more Mobile Stations (MSs), and, when Channel Quality Information (CQI) feedback information relating to the determined MU-MIMO chunks and the determined SU-MIMO chunks is received from the MSs, allocating chunks and streams for MU-MIMO/SU-MIMO to users who maximize overall capacity using the CQI feedback information.

Abstract: An apparatus and method for feeding back Channel Quality Information (CQI) in a wireless communication system are provided. Total channels are grouped into certain number of groups according to downlink channel estimates. Group indexes are determined for the channels. Feedback information is generated using the group indexes of the channels and representative values of the groups. Then, the generated feedback information can be transmitted.

Abstract: A transmitting apparatus and method in an OFDM system are provided. In the transmitting apparatus, a channel information receiver receives channel information. A rate allocator calculates a variable data rate. A scheduler allocates channel resources according to the channel information and the variable data rate.