Abstract: A method of performing relay communication in a next generation cellular communication system is disclosed. The next generation cellular communication system includes a base station and a plurality of terminals, and a communication target terminal which has not acquired a Line-Of-Sight (LOS) channel with the base station performs communication through the relay of a relaying terminal which has acquired a LOS channel. The base station determines the relaying terminal. The relaying terminal forms a relaying terminal group by determining one or more relaying assistant terminals. The communication target terminal forms a transmitting/receiving terminal group by determining one or more transmitting/receiving assistant terminals. The base station performs communication with the relaying terminal through the relaying terminal, relaying assistant terminals of the relaying terminal group and the transmitting/receiving assistant terminals of the transmitting/receiving terminal group.

Abstract: There is provided to a method for encoding an LDPC (Low Density Parity Check) code using the result of checking a previously specified parity, including the steps of: forming a parity bit check matrix having a dual diagonal structure consisting of (N-K) rows for check nodes and (N-K) columns on the basis of the H matrix; calculating the values of all the parity bits by inserting a given binary value in sub-blocks, with the parity bit check matrix formed on the H matrix; if the values of the parity bits are incorrect, checking the parity bit corresponding to the sub-block located in the last part of the H matrix; searching the parity bit parts where the parity bit check result is represented as “1”; performing an XOR operation in sub-blocks on the parity bit part obtained through a simultaneous equation between the parity bits of the searched parity bit parts and the parity bit parts; and determining the value of the parity bit satisfying the condition that the value obtained by multiplying the H matrix by a c

Abstract: Disclosed is an apparatus for receiving data in a communication system, including: a receiving unit configured to receive data transmitted from an access point (AP) by a multi-input multi-output (MIMO) scheme; a detecting unit configured to detect a data stream of the received data using an LQ decomposition scheme; a generating unit configured to generate channel information regarding the data stream; and a transmitting unit configured to feedback the channel information to the AP.

Abstract: Provided are an apparatus for receiving signals in an OFDM communication system using multiple transmission/reception antennas and a method thereof. The method includes modulating a predetermined part of a data stream based on a multi-dimensional reception procedure to generate a first modulated data stream; regenerating a symbol corresponding to the modulated data stream; eliminating the regenerated symbol from a remained data stream; modulating the eliminated data stream to generate a second modulated data stream; and outputting an output signal obtained by serializing the first modulated data stream and the second modulated data stream.

Abstract: In the present invention, data generated from a source unit are distributed to at least one bandwidth; the data distributed to the respective bandwidths are encoded in order to perform an error correction; the encoded data are distributed to at least one antenna; a subcarrier is allocated to the data distributed to the respective antennas, and an inverse Fourier transform is performed; a short preamble and a first long preamble corresponding to the subcarrier are generated; a signal symbol is generated according to a data transmit mode; and a frame is generated by adding a second long preamble between the signal symbol and a data field for the purpose of estimating a channel of a subcarrier which is not used.

Abstract: In the present invention, data generated from a source unit are distributed to at least one bandwidth; the data distributed to the respective bandwidths are encoded in order to perform an error correction; the encoded data are distributed to at least one antenna; a subcarrier is allocated to the data distributed to the respective antennas, and an inverse Fourier transform is performed; a short preamble and a first long preamble corresponding to the subcarrier are generated; a signal symbol is generated according to a data transmit mode; and a frame is generated by adding a second long preamble between the signal symbol and a data field for the purpose of estimating a channel of a subcarrier which is not used.

Abstract: In the present invention, data generated from a source unit are distributed to at least one bandwidth; the data distributed to the respective bandwidths are encoded in order to perform an error correction; the encoded data are distributed to at least one antenna; a subcarrier is allocated to the data distributed to the respective antennas, and an inverse Fourier transform is performed; a short preamble and a first long preamble corresponding to the subcarrier are generated; a signal symbol is generated according to a data transmit mode; and a frame is generated by adding a second long preamble between the signal symbol and a data field for the purpose of estimating a channel of a subcarrier which is not used.

Abstract: An apparatus and a method of performing radio communication are provided. The radio communication apparatus may determine a channel capacity of a radio channel based on a sensing duration to sense the radio channel and a false alarm probability, determine a sensing duration value and a false alarm probability value that maximize the channel capacity, and sense the radio channel based on the determined sensing duration value and the false alarm probability value.

Abstract: A pilot signal power control apparatus to determine a power level of a pilot signal of a primary network to indicate an availability of a wireless resource of thereof to a secondary user of a secondary network according to a cognitive radio technology, the pilot signal power control apparatus and an operation method thereof, the pilot signal power control apparatus including: a prediction unit to predict a noise increase and/or a sensing probability, the noise increase occurring in a primary user of the primary network due to a channel estimation error, and the sensing probability being a probability that a secondary user senses the pilot signal of; a channel capacity calculation unit to calculate a channel capacity of the primary user based on the predicted noise increase and/or sensing probability; and a power level determination unit to determine the power level of the pilot signal using the calculated channel capacity.

Abstract: Provided is a method, and an apparatus and communication system to perform the method, of detecting a victim terminal and performing an interference coordination in a multi-cell environment. The multi-cell environment may include a heterogeneous cell environment including a small cell and a macro cell. The method includes determining whether a macro terminal is located within a cell coverage of a small base station, and adjusting the cell coverage according to the determination.

Abstract: The present invention relates to an orthogonal frequency division multiplexing wireless local area network (LAN) transmitting/receiving system for providing expanded service coverage, and a method thereof. A first OFDM modulation is performed for an even-numbered time, and a second OFDM modulation is performed for an odd-numbered time. A transmitting frame including a plurality of signal fields according to the first and second OFDM modulation is transmitted. The receiving system determines whether a signal field is repeatedly generated in the frame. If the signal field is not repeatedly generated, corresponding demodulation is performed. If repeatedly performed, the signal field is demodulated by using first bit allocation information and second bit allocation information having a ½ value of the first bit allocation information. A data field is demodulated according to the demodulated signal field.

Abstract: In the present invention, data generated from a source unit are distributed to at least one bandwidth; the data distributed to the respective bandwidths are encoded in order to perform an error correction; the encoded data are distributed to at least one antenna; a subcarrier is allocated to the data distributed to the respective antennas, and an inverse Fourier transform is performed; a short preamble and a first long preamble corresponding to the subcarrier are generated; a signal symbol is generated according to a data transmit mode; and a frame is generated by adding a second long preamble between the signal symbol and a data field for the purpose of estimating a channel of a subcarrier which is not used.

Abstract: A method of performing relay communication in a next generation cellular communication system is disclosed. The next generation cellular communication system includes a base station and a plurality of terminals, and a communication target terminal which has not acquired a Line-Of-Sight (LOS) channel with the base station performs communication through the relay of a relaying terminal which has acquired a LOS channel. The base station determines the relaying terminal. The relaying terminal forms a relaying terminal group by determining one or more relaying assistant terminals. The communication target terminal forms a transmitting/receiving terminal group by determining one or more transmitting/receiving assistant terminals. The base station performs communication with the relaying terminal through the relaying terminal, relaying assistant terminals of the relaying terminal group and the transmitting/receiving assistant terminals of the transmitting/receiving terminal group.

Abstract: A digital system design method uses a higher programming language. In order to realize a digital system, an algorithm is verified based on a program written by the higher programming language and a program is programmed considering the higher programming language-hardware characteristics before the program is written in the lower programming language, and thus conversion into the lower programming language may be easily performed.

Abstract: In the present invention, data generated from a source unit are distributed to at least one bandwidth; the data distributed to the respective bandwidths are encoded in order to perform an error correction; the encoded data are distributed to at least one antenna; a subcarrier is allocated to the data distributed to the respective antennas, and an inverse Fourier transform is performed; a short preamble and a first long preamble corresponding to the subcarrier are generated; a signal symbol is generated according to a data transmit mode; and a frame is generated by adding a second long preamble between the signal symbol and a data field for the purpose of estimating a channel of a subcarrier which is not used.

Abstract: The present invention is related to a beam division multiple access system and a method thereof. The base station according to the present invention comprises a initial mobile station information receiver for receiving initial mobile station information that a mobile station omnidirectionally transmits in an initial communication step, a mobile station location and speed detector for detecting a location and a moving speed of the mobile station from the initial mobile station information, a downlink beam generator for generating a downlink beam based on the location and the moving speed of the mobile station transferred from the mobile station location and speed detector, and adjusting at least one of a width and a direction of each the downlink beam, and a downlink beam transmitter for transmitting the downlink beam generated by the downlink beam generator to the mobile station through a phase array antenna.

Abstract: An exemplary automatic gain control device includes: a radio frequency receiver for receiving a plurality of first signals through a plurality of antennas, respectively controlling gains of the plurality of first received signals, and outputting the plurality of the first signals having the controlled gain as a plurality of second signals; a signal saturation detecting unit for outputting a saturation index determination value when the number of plurality of second signals that are greater than a threshold value is greater than a predetermined number; and a gain controlling unit for comparing power values of the plurality of second signals to detect one power value, and outputting a gain value determined based on a detected power value and a saturation index determination value to the radio frequency receiver.

Abstract: There is provided to a method for encoding an LDPC (Low Density Parity Check) code using the result of checking a previously specified parity, including the steps of: forming a parity bit check matrix having a dual diagonal structure consisting of (N-K) rows for check nodes and (N-K) columns on the basis of the H matrix; calculating the values of all the parity bits by inserting a given binary value in sub-blocks, with the parity bit check matrix formed on the H matrix; if the values of the parity bits are incorrect, checking the parity bit corresponding to the sub-block located in the last part of the H matrix; searching the parity bit parts where the parity bit check result is represented as “1”; performing an XOR operation in sub-blocks on the parity bit part obtained through a simultaneous equation between the parity bits of the searched parity bit parts and the parity bit parts; and determining the value of the parity bit satisfying the condition that the value obtained by multiplying the H matrix by a c

Abstract: Provided are an apparatus for receiving signals in an OFDM communication system using multiple transmission/reception antennas and a method thereof. The method includes modulating a predetermined part of a data stream based on a multi-dimensional reception procedure to generate a first modulated data stream; regenerating a symbol corresponding to the modulated data stream; eliminating the regenerated symbol from a remained data stream; modulating the eliminated data stream to generate a second modulated data stream; and outputting an output signal obtained by serializing the first modulated data stream and the second modulated data stream.

Abstract: Disclosed is an adaptive receiving MIMO (multi input and multi output) system and method which decides a symbol detecting order so as to estimate the symbol having the minimum summation of weights of least square errors at the time of estimating the symbol for respective equalizers provided in parallel by the number of transmit antennas, and updates filter tap coefficients based on the RLS algorithm according to the detecting orders. Therefore, the filter tap coefficients are directly updated without tracking channels in the time-varying channel environment, and accordingly, detection performance very similar to those of the channel tracking and conventional V-BLAST scheme is provided with reduced complexity.