Abstract: A space frequency block code signal relaying system is provided. The space frequency block code signal relaying system includes a signal detecting unit which receives, via a radio channel, a source signal sent from a source station and detects the received signal; a relay signal generation unit which generates a relay signal corresponding with the source signal transmitted from the source station to a destination node based on the received signal, the source signal and the relay signal being signals encoded in a Space Frequency Block Code (SFBC) scheme; and a signal transmitting unit which transmits the relay signal to the destination node.

Abstract: A method and apparatus for compensating a distortion due to a clipped amplitude when an amplitude of a signal is clipped to reduce a peak to average power ratio (PAPR) in a wireless communication system using an orthogonal frequency division multiplexing (OFDM) scheme and a transmit diversity method using an orthogonal coding. A wireless data transmission apparatus which transmits a data stream via a plurality of antennas, the apparatus including: a coding unit which Space-Time block codes a first data stream into a plurality of second data streams, the plurality of second data streams being orthogonal to each other; an inverse Fourier transform unit which performs an inverse Fourier transform of each of the Space-Time block coded second data stream and generates a plurality of time domain signals; and a plurality of amplitude clipping units which clips an amplitude of each of the plurality of generated time domain signals.

Abstract: A receiving apparatus in an OFDM communication system, in which the receiving apparatus includes a serial-to-parallel converter that converts a serial signal received through an antenna to parallel signals. A pre-processor processes an nth symbol converted in the serial-to-parallel converter using an (n?1)th symbol and an (n+1)th symbol. A Fourier transformer Fourier-transforms the output of the pre-processor and an equalizer equalizes a Fourier-transformed signal. A deinterleaver deinterleaves an equalized signal, a decoder decodes a deinterleaved signal, and a parallel-to-serial converter converts parallel decoded signal to a signal stream.

Abstract: A method and apparatus for transmitting and receiving data by performing an iterative multi-user detection is provided.

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 mobile communication system, a transmitter includes a first transmission antenna and a second transmission antenna, and the first and second transmission antennas transmit signals through at least one odd carrier and at least one even carrier. The transmitter determines a first symbol and a second symbol to be used for initial channel estimation of a receiver, encodes the first symbol and the second symbol by a preset transmit diversity scheme for a preset time, and transmits the encoded first and second symbols to the receiver through odd carriers and even carriers of the first transmission antenna and the second transmission antenna.

Abstract: Provided are an apparatus for reducing clipping noise in a broadband wireless communication system in which a clipping method is used and a method thereof. The method includes, when clipped signals are received, decoding and equalizing the received signals to determine transmitted symbols, comparing the magnitudes of the amplitudes of the determined transmitted symbols with a predetermined reference value, and reconstructing signals using the amplitudes of the transmitted symbols and the phases of the received signals when it is determined that the magnitudes of the amplitudes of the transmitted symbols are greater than the reference value.

Abstract: A receiver for ICI cancellation in a MIMO system is provided, in which a detection orderer determines a subcarrier detection order according to SINRs of subcarriers in an I-CMOS, a detector receives a vector on the subcarriers and a priori information from a decoder according to the subcarrier detection order and iteratively estimates the received vector using the a priori information, and the decoder decodes an ICI-cancelled signal according to the estimate.

Abstract: A method and apparatus for transmitting and receiving a signal in a wireless communication system. The wireless communication system includes a transmitter with at least four transmit antennas and a receiver with at least one receive antenna. Space Frequency Block Coding (SFBC) processes are performed for input signals on a basis of two antenna pairs. Signal blocks whose number corresponds to the number of transmit antennas are output. A Space Time Block Coding (STBC) process is performed for the signal blocks generated according to the antenna pairs. Signals carried by single carriers are transmitted through the at least four transmit antennas mapped to the signal blocks.

Abstract: Disclosed is a VDSL (very high bit-rate digital subscriber line) system on the DMT line coding method basis and a method for determining a length of cyclic prefix samples using the system. The VDSL system comprises a transmitter data including cyclic prefix samples through a channel; a receiver for receiving the data including the cyclic prefix samples; a controller for controlling the transmitter and the receiver to control an initialization operation including handshake, training, channel analysis, and exchange, and a data transmission operation after the initialization operation; and a cyclic prefix sample length estimator for estimating an optimized length of the cyclic prefix sample on the basis of the correlation between the cyclic prefix sample and other data.

Abstract: Disclosed is a transceiving apparatus and method in which a space frequency block coding (SFBC) technique is applied to the SC-FDE technique. The transceiving method encodes an input signal into frequency-domain blocks so as to output at least two signal blocks in parallel to each other, inserts a cyclic prefix (CP) into the output signal blocks, and outputs the signal blocks through the same sub-channel by means of corresponding antenna.

Abstract: An apparatus and method for channel estimation and CP reconstruction in an OFDM-STBC mobile communication system are provided. An ISI canceller cancels ISI signal components from first and second received symbol sequences. A cyclicity restorer cancels ICI signal components from the ISI-cancelled first received symbol sequence and the ISI-cancelled second received symbol sequence. A recoverer acquires the recovered sequence estimates of the ICI-cancelled first received symbol sequence and the ICI-cancelled second received symbol sequence by decoding. The ICI cancellation of the ISI-cancelled first and second received symbol sequences and the ISI cancellation of the second received symbol sequence are iterated a predetermined number of times.

Abstract: A new diversity scheme for orthogonal frequency division multiplexing/multi-input multi-output (OFDM/MIMO) systems. The new diversity scheme, i.e., turbo layered space-frequency coded OFDM (TLSFC-OFDM), uses the turbo principle with space hopping (SH). The TLSFC-OFDM system uses a successive interference cancellation (SIC) algorithm to reduce the number of iterations. As a result, this scheme reduces computational complexity. Simulation results show that the SIC-based TLSFC-OFDM system outperforms a conventional OFDM/Horizontal Bell Labs Layered Space-Time (H-BLAST) system using a horizontal coding scheme.

Abstract: Disclosed is a VDSL (very high bit-rate digital subscriber line) system on the DMT line coding method basis and a method for determining a length of cyclic prefix samples using the system. The VDSL system comprises a transmitter data including cyclic prefix samples through a channel; a receiver for receiving the data including the cyclic prefix samples; a controller for controlling the transmitter and the receiver to control an initialization operation including handshake, training, channel analysis, and exchange, and a data transmission operation after the initialization operation; and a cyclic prefix sample length estimator for estimating an optimized length of the cyclic prefix sample on the basis of the correlation between the cyclic prefix sample and other data.

Abstract: Disclosed is a multicarrier-based wireless communication system including a base station for providing a multiple access service to terminals which filter multitone transmitting signals through filters and transmit the filtered signals. A transmitter of the respective terminals includes a multiplexer for multiplexing an input signal and outputting the signal as a plurality of transmitting signals, at least one filter bank for filtering the plurality of transmitting signals, an inverse fast Fourier transformer for executing inverse fast Fourier transform of the filtered transmitting signals output from the filter bank, and a filter information generator for providing filter information to the filter bank. Since the transmitter of the present invention distinguishes users from each other by a filter and thus no synchronization is required between users, which causes a problem in an uplink of the multicarrier-based wireless communication system, system performance can be expected to be improved.

Abstract: A receiving apparatus in an OFDM communication system, in which the receiving apparatus includes a serial-to-parallel converter that converts a serial signal received through an antenna to parallel signals. A pre-processor processes an nth symbol converted in the serial-to-parallel converter using an (n?1)th symbol and an (n+1)th symbol. A Fourier transformer Fourier-transforms the output of the pre-processor and an equalizer equalizes a Fourier-transformed signal. A deinterleaver deinterleaves an equalized signal, a decoder decodes a deinterleaved signal, and a parallel-to-serial converter converts parallel decoded signal to a signal stream.

Abstract: A mobile communication system, a transmitter includes a first transmission antenna and a second transmission antenna, and the first and second transmission antennas transmit signals through at least one odd carrier and at least one even carrier. The transmitter determines a first symbol and a second symbol to be used for initial channel estimation of a receiver, encodes the first symbol and the second symbol by a preset transmit diversity scheme for a preset time, and transmits the encoded first and second symbols to the receiver through odd carriers and even carriers of the first transmission antenna and the second transmission antenna.

Abstract: A preprocessing apparatus and method for a transmitter and a receiver to prevent system performance degradation caused by Inter-Channel Interference (ICI) or inter-symbol interference (ISI) in an OFDM system. In the OFDM system using N carriers having different frequency bands and K carriers of the N carriers designated as redundant carriers, the transmitter renders ICI-causing parts to be zeroes in a data frame, when a cyclic prefix is not longer than a channel impulse response. Therefore, the ICI is prevented. The receiver eliminates the ISI involved in a current frame using an interference estimated from a previous data frame. Therefore, noise spread caused by the use of redundant carriers is prevented and system complexity is remarkably reduced.

Abstract: A decision feedback equalizer and a method for updating tap coefficients of the decision feedback equalizer are provided. The decision feedback equalizer (DFE) includes a first equalizer for reducing channel interference noise in an input signal, a second equalizer for generating a feedback signal for reducing remaining interference noise, and an update controller for controlling the first and the second equalizers so as to freeze the second equalizer when the first equalizer is updated and to freeze the first equalizer when the second equalizer is updated. The tap coefficients of the feedforward equalizer and the feedback equalizer are alternately initialized. It then becomes possible to stably converge the levels of respective tap coefficients without diverging them and to reduce the power used for updating the tap coefficients in a steady state.

Abstract: A digital subscriber line receiving apparatus having resilience to HAM radio interference noise and a method therefore includes an automatic gain controller for amplifying a received signal level to a signal level having a predetermined magnitude, a timing recoverer for recovering timing from a signal output from the automatic gain controller, an equalizer for removing interference noise from a signal received from the timing recoverer, a slicer for detecting a digital value from a signal received from the equalizer, an initialization controller for resetting the receiving apparatus and initializing the automatic gain controller, the timing recoverer, and the equalizer when the signal to noise ratio of the output signal of the equalizer is smaller than a reference signal to noise ratio, and an update controller for preventing automatic gain controller and equalizer from being initialized by the initialization controller when HAM radio interference noise is detected in the received signal.