Abstract: A cognitive radio communication terminal including a transmission processing unit to divide data by a quiet time slot that is allocated at a first point in time of a collision detection period, to transmit at least one portion of the divided data to a reception side, and a sensing unit to determine whether at least one of a feature information and an energy of another terminal is detected in a channel with the reception side during the quiet time slot of the first point in time. Where neither the feature information nor the energy of the other terminal is detected based on a determination of the sensing unit, the transmission processing unit transmits the remaining divided data.

Abstract: A wireless network using a network coding scheme is provided. The wireless network may include at least two source nodes, at least two destination nodes, and a relay node. The at least two source nodes may divide source messages into partial source messages, and transmit the partial source messages to the relay node. The relay node may generate a network-coded message using the network coding scheme. The at least two destination nodes may overhear the partial source messages using overhearing channels and obtain the source messages based on the received network-coded message.

Abstract: An apparatus and method of facilitating cooperation within a cognitive radio communication system. The cooperation system facilitated in the communication system by another communication system. The apparatus include: a receiver to receive an uplink signal from a mobile station and a cooperation signal from a second communication system, wherein the cooperation signal is associated with the uplink signal; an evaluator to evaluate a contribution of the cooperation signal with respect to detection of the uplink signal; and a radio resource management unit to control an available radio resource for the second system according to the contribution of the cooperation signal.

Abstract: A data communication network to transmit and/or receive data using soft-decision information is provided. A target access point in a data communication network may compute soft-decision information with respect to information bits corresponding to a transmission symbol, and transmit the computed soft-decision information to a destination device or an access point connected to the destination device. The destination device or the access point connected to the destination device may combine soft-decision information of a plurality of access points, and detect information bits based on the combined soft-decision information.

Abstract: Disclosed are an apparatus and a method for generating a preamble sequence in an orthogonal frequency division multiplexing communication system including a reference base station and a plurality of non-reference base stations and employing m sub-carriers in a frequency domain. A reference preamble sequence having a length equal to n is generated and mapped on a one-to-one basis with n sub-carriers of the m sub-carriers. A final preamble sequence equivalent to the reference preamble sequence is generated when the base station is a reference base station, or a phase of the reference preamble sequence is shifted by a predetermined phase in order to generate a phase-shifted final preamble sequence when the base station is a non-reference base station, thereby minimizing interference between neighbor base stations.

Abstract: Disclosed is a method for acquiring synchronization in a mobile communication system using an Orthogonal Frequency Division Multiplexing (OFDM) scheme. The method includes modeling a power delay profile in time-varying frequency selective fading channel conditions by a specific function; detecting a log probability distribution function of a timing offset and a frequency offset in consideration of a correlation between a received signal and the received multi-path signal in the time-varying frequency selective fading channel conditions having the power delay profile modeled as the specific function; and estimating a timing offset and a frequency offset which maximize the log probability distribution function of the timing offset and the frequency offset.

Abstract: An apparatus and method for channel estimation using preamble signals received from a serving Node B and neighboring Node Bs each having N (?1) transmit antennas in a UE having M (?1) receive antennas in a broadband wireless communication system. In the channel estimation apparatus, a Node B number decider calculates the maximum number NS of channel-estimatable Node Bs using a preamble length, the number of antennas in each of the Node Bs, and the number of multiple paths. A multi-cell preamble matrix generator generates a multi-cell preamble matrix xS by generating a Node B preamble matrix for each of the Node Bs and selecting NS Node B preamble matrices according to reception power among the Node B preamble matrices. A channel estimator performs a channel estimation using xS and signals received through the M antennas during a preamble receiving period.

Abstract: Disclosed is a differential space-time block coding apparatus with a high transmission rate in a wireless communication system employing multiple transmit antennas and a method thereof. The differential space-time block coding method includes the steps of, when elements of a transmission matrix B43v are transmitted in a predetermined block (a vth block) through a predetermined transmit antenna at a predetermined time, modulating a symbol Sv of inputted binary data to a symbol Sv+1, creating a matrix S44v+1 in a block (a (v+1)th block) following the predetermined block by substituting the modulated symbol for the matrix P44, and then, in order to perform a differential encoding function, multiplying the matrix B43v by the matrix S44v+1 so as to calculate a new matrix B43v+1 to be transmitted in the (v+1)th block.

Abstract: A mobile communication system includes M transmission antennas, P encoders for receiving P information bit streams and encoding the received information bit streams with a space-time trellis code (STTC), and M modulators for modulating information bit streams output from the P encoders in a predetermined modulation scheme and outputting modulation symbol streams. A sequence used for channel estimation is generated, and the sequence is transmitted in substitute for at least one modulation symbol in a predetermined position through the M transmission antennas, for each of the modulation symbol streams output from the M modulators.

Abstract: A transmission method based on random beamforming. A base station receives, from mobile stations, feedback information including channel-by-channel transmission rates for a weight vector arbitrarily set by the base station. The base station compares transmission rates of identical channels received from the mobile stations. The base station allocates an associated channel to a mobile station with a large transmission rate and transmits a signal through the allocated channel. The transmission method based on random beamforming can improve fairness and efficiency of a resource allocation by simultaneously allocating different channels to multiple terminals and can increase a total system capacity through the improved fairness and efficiency.

Abstract: Provided are a method and apparatus for compensating for a frequency offset in an interleaved frequency division multiple access. The method compensates for a frequency offset between a transmission signal and a reception signal for a uth user (1?u?U, where U denotes the number of users) in an interleaved frequency division multiple access.

Abstract: A transmitter and a receiver are disclosed herein that support transmit antenna diversity using space-time block coding in a wireless communication system. The transmitter produces symbol combinations containing, as their elements, input symbols, the inversions and conjugates of the symbols, and symbols obtained by rotating the phases of the symbols once, forms a matrix having symbols in at least two columns orthogonal to each other with the symbol combinations, and transmits the matrix. The receiver detects symbols that minimize maximum likelihood (ML) decoding metrics over all possible symbols using channel gains from transmit antennas to a receive antenna. Also, the receiver selects candidate symbols among all possible symbols according to the characteristics of transmitted modulation symbols and detects symbols that minimize the ML decoding metrics.

Abstract: A mobile communication system includes M transmission antennas, P encoders for receiving P information bit streams and encoding the received information bit streams with a space-time trellis code (STTC), and M modulators for modulating information bit streams output from the P encoders in a predetermined modulation scheme and outputting modulation symbol streams. A sequence used for channel estimation is generated, and the sequence is transmitted in substitute for at least one modulation symbol in a predetermined position through the M transmission antennas, for each of the modulation symbol streams output from the M modulators.

Abstract: Disclosed herein is a scheduling method and apparatus based on eigen values robust against spatial correlation in a mobile communication system supporting multiple users by use of multiple transmit/receive antennas. A user terminal estimates channel characteristics from the transmit antennas to the user terminal, decomposes the estimated channel characteristics into receive channel characteristics and transmit channel characteristics, and feeds back a transmit principal eigen vector to the base station (BS). The BS selects a predetermined number of user terminals having the least correlation using the feedback principal eigen vectors from a plurality of user terminals, constructs a user precoding matrix by combining the principal eigen vectors of the selected user terminals, multiplies data streams for the selected user terminals by the user precoding matrix and transmits the multiplied data to the selected user terminals.

Abstract: An apparatus and method for full-diversity, full-rate space-time block coding in a transmitter using two Tx antennas are provided. An input symbol sequence is STBC-encoded in a predetermined method and transmitted through the two Tx antennas.

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: In the ICI cancellation method for OFDM communication system, a receiver performs channel estimation using pilot subcarriers included in transmission signals transmitted from at least one transmitter. The transmitter generates the transmission signal in which pilot subcarriers and data subcarriers are regularly arranged, performs preceding on the transmission signal, modulates the pre-coded transmission signal into an OFDM symbol, and transmits the OFDM symbol. The receiver receives the OFDM symbol; demodulates the OFDM symbol, detects the pilot subcarriers from a demodulated signal, estimates channels using the pilot subcarriers, and restores the transmission signal using the estimated channels.

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 transmitter and a receiver are disclosed herein that support transmit antenna diversity using space-time block coding in a wireless communication system. The transmitter produces symbol combinations containing, as their elements, input symbols, the inversions and conjugates of the symbols, and symbols obtained by rotating the phases of the symbols once, forms a matrix having symbols in at least two columns orthogonal to each other with the symbol combinations, and transmits the matrix. The receiver detects symbols that minimize maximum likelihood (ML) decoding metrics over all possible symbols using channel gains from transmit antennas to a receive antenna. Also, the receiver selects candidate symbols among all possible symbols according to the characteristics of transmitted modulation symbols and detects symbols that minimize the ML decoding metrics.

Abstract: Apparatuses and methods for efficiently transmitting and receiving multicast data having a scalable data structure preferably provide for the transmission of a first data stream at a basic data rate using a first modulation scheme that can be received by all receivers in a communications system, while simultaneously providing for the transmission of at least a second data stream at a higher data rate using a second modulation scheme that can be received by groups of receivers having higher data rate capabilities, thereby maximizing data communications to all receivers in the communications system. The transmitting apparatus preferably includes a stream generator that divides multicast data into a plurality of multicast streams, an encoding processor, a header processor that generates a header for each of the encoded multicast streams, a stream modulator that modulates each of the encoded multicast streams, and a frame generator for generating a transmission frame.