Abstract: Disclosed are an apparatus and a method for reducing the coding complexity in an LDPC code used in a digital communication system. In the method, parameters required for coding are determined according to a coding rate and a code length, a seed matrix is generated according to values of the parameters, a plurality of cell matrices are generated according to the values of the parameters, a parity check matrix is generated using the seed matrix and the cell matrix, and information bits are coded from the parity check matrix. The method can be realized by a small memory and a simple shift register and can perform coding even without obtaining a generation matrix, thereby remarkably reducing the complexity of a system.

Abstract: Provided is a method of compensating for energy loss and eliminating inter-symbol interference (ISI) and inter-chip interference (ISI) in wireless signals, and a rake receiver for wireless LANs adopting the same. The rake receiver compensates for energy loss of a CCK signal transmitted in a multi-path wireless channel environment and eliminates ISI and ICI from the received CCK signal because a DFE structure per chip used for calculating ICI components, is connected in parallel with a DFE structure per symbol, thus eliminating ISI and ICI components.

Abstract: A method and apparatus for detecting a signal in a communication system using at least two transmit antennas are provided. The signal detection method and apparatus includes selecting a symbol corresponding to a lowest branch metric from among symbols, the number of which corresponds to a modulation scheme, determining a candidate symbol by extending a process of selecting a symbol corresponding to a lowest branch metric from among the selected symbols, to a number which is less by one than the number of the transmit antennas, setting an accumulated branch metric of the candidate symbol as a threshold, removing a symbol having an accumulated branch metric higher than the threshold, and selecting, as a last received symbol, a symbol corresponding to a path having the lowest accumulated branch metric among paths selected without being removed until a last stage.

Abstract: A method and system of relaying data are provided. The data is encoded into a turbo codeword by using a convolutional turbo code, and the turbo codeword is transmitted from a source to a relay and a destination by first puncturing the turbo codeword. The first punctured turbo codeword which is received in the relay is decoded and the decoded turbo codeword is transmitted from the relay to the destination by second puncturing the decoded turbo codeword. The turbo codeword received from the source and the relay to the destination are totaled respectively as a single turbo codeword and the totaled single turbo codeword is decoded and the data is recovered.

Abstract: Provided is a constellation rotation relay system and constellation rotation relay method which can acquire full diversity gain by performing constellation rotation for a channel matrix in a relay network when configuring a virtual MIMO channel. The constellation rotation system includes a matrix creator for creating a symbol matrix by configuring a symbol transmitted in parallel from a source of a relay network; and a constellation rotation unit constellation rotating the symbol in the symbol matrix by adding a constellation rotation matrix to the created symbol matrix.

Abstract: An OFDM receiving device for adjusting a beam formation azimuth through a plurality of antennas, a communication device using the same, and a method thereof.

Abstract: Provided is a receiver of a multi-input multi-output system using multiple antennas, the receiver including: a first multiplying unit for multiplying a vector r received via the antenna by a Hermitian matrix Q; a candidate transmitting vector generating unit for detecting a signal on a lowest modulation order transmitting antenna from the received vector y output from the first multiplying unit, creating as many symbol candidates as the modulation order of the detected signal, and generating a candidate transmitting vector using each symbol candidate; a transmitting vector determining unit for obtaining a distance between each candidate transmitting vector generated by the candidate transmitting vector generating unit and the received vector y to determine a final transmitting vector; and a demodulating unit for demodulating the final transmitting vector determined by the transmitting vector determining unit.

Abstract: A receiver performing a stable operation in a burst mode is provided. The receiver transmits packet data using a preamble, and has good acquisition performance so that a synchronization part converges on a preamble interval. For the acquisition performance, the receiver senses the carrier of a received signal, detects a rough location of a burst, and in response to the result of carrier sensing, performs coarse gain control, symbol timing compensation, and frame synchronization. Then, if the frame synchronization is completed, in response to the result of frame synchronization, the receiver performs fine gain control, equalization of the signal, and carrier recovery.

Abstract: An apparatus and method for lowering a tree searching complexity in a Spatial Multiplexing (SM) Multiple Input Multiple Output (MIMO) antenna system are provided. A transmitting apparatus includes a generator for generating a plurality of transmit streams by spatial-multiplexing a transmit data, a determiner for determining modulation schemes to be applied to the plurality of the transmit streams respectively and a modulator for modulating the plurality of the transmit streams using at least two modulation schemes under control of the determiner. The receiver detects the signals by allocating the modulation scheme of the lowest order to the upper tree level.

Abstract: An apparatus is provided for detecting a signal in a communication system using a Multiple Input Multiple Output (MIMO) scheme. The signal detection apparatus includes a detector for generating second matrixes by extending a first matrix composed of channel response vectors, generating specific matrixes by decomposing the second matrixes, generating a lattice point of vectors constituting the second matrixes, estimating a signal using the generated specific matrixes and lattice point, and detecting the estimated signal as a received signal if the estimated signal has a value within a predetermined allowable range.

Abstract: Provided are a user interface method of enabling a user to conveniently use a terminal allowing multi-tasking, and a computer readable recording medium storing the method. The user interface method includes classifying applications capable of being executed by the apparatus into groups, in such a manner as to classify one or more applications that perform similar functions into the same group; and displaying a window for executing a corresponding application, for each of the groups.

Abstract: A method for generating a parity check matrix of a Low Density Parity Check (LDPC) code. A base matrix is generated in which elements with a value of 1 are arranged at predefined distances. The elements with the value of 1 in the base matrix are replaced with predefined sub-matrices. The method can improve the performance of the LDPC code by implementing the parity check matrix in which the number of 4-cycles or 6-cycles adversely affecting the LDPC code performance is minimized.

Abstract: A channel equalizing and carrier recovery system for home phoneline networking alliance (HomePNA) receiver and method thereof are provided. The channel equalizing system includes a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer and a quadrature amplitude modulation (QAM) equalizer. The FD-QAM equalizer receives an FD-QAM signal, determines FD-QAM tap coefficients, and equalizes the FD-QAM signal using the FD-QAM tap coefficients. The QAM equalizer receives a QAM signal, determines QAM tap coefficients, and equalizes the QAM signal using the QAM tap coefficients. The QAM equalizer receives the FD-QAM signal and determines the QAM tap coefficients during a predetermined header period. The carrier recovery circuit includes a phase detector, a loop filter, and a numerically controlled oscillator (NCO).

Abstract: A digital multimedia broadcasting receiver and a channel managing method of the same. The digital multimedia broadcasting receiver includes a tuner that receives a broadcasting signal including a carrier frequency and multiple broadcast programs carried by the carrier frequency, a demodulating unit that demodulates the received broadcasting signal, and a controller that classifies a broadcast program of the demodulated broadcasting signal according to a broadcast program type, and selectively displays the classified broadcast program through a graphical user interface.

Abstract: An image forming apparatus and a method for providing a file list using the same. The image forming apparatus comprises a user interface for inputting an address of a File Transfer Protocol (FTP) server, a network interface for accessing the FTP server corresponding to the input address of the FTP server and receiving file information, a list generator for generating a file list based on the receiving file information, and a print part for generating an image of the generated file list and outputting the image. Accordingly, the image forming apparatus provides a user with file information provided from the FTP server.

Abstract: A method and an apparatus are provided for displaying ensembles and services provided by digital multimedia broadcasting (DMB) so that a user can search for and select a desired service, and can determine, register, and manage a preferred service according to the user's inclination for watching TV. The method relates to displaying a broadcast program schedule provided by a digital multimedia broadcasting, and includes displaying ensembles included in the broadcast program schedule on a first window of a screen, and displaying services linked to each of the ensembles on a second window of the screen. Accordingly, it is possible for the user to easily view and select ensembles and services provided by DMB.

Abstract: An image forming device for transmitting and receiving an email message and a method for transmitting and receiving an email message by an image forming device. The image forming device includes a communication unit, a memory unit, an email processing unit, an email preparing unit, and a controller. The communication unit is connected to a network connected to a predetermined terminal device and performs data communication with the terminal device. The memory unit stores a pre-processed data file. The email processing unit detects the content of any email messages that are transmitted from the terminal device and received through the communication unit. The email preparing unit prepares an email message to be transmitted to the terminal device.

Abstract: A digital multimedia broadcast (DMB) receiver and a user interface including a processor that processes the received DMB signal and extracts information regarding ensembles and services from the DMB signal so that the user interface can display received services using the extracted information regarding the ensembles and services. The user interface can be a grid-type interface which includes an ensemble axis and a service axis to display multiple services linked to an ensemble along with the total duration of each service and the duration that each service has been viewed so that a user can easily determine the current status of each service.

Abstract: An improved receiver for a multicarrier-based MIMO (Multiple-Input Multiple-Output) system is provided. A MIMO receiving apparatus includes a detection priority decision unit, which receives via N receiving antennas signals transmitted from M transmitting antennas and determines the detection priorities of the signals, and a signal detector, which successively detects the signals in a decreasing order from a signal having a higher priority according to the detection priorities determined by the detection priority decision unit. System complexity can be reduced by minimizing the number of the inverse matrix calculations required for an SIC mechanism using one MIMO DFE and MISO DFEs corresponding to the number of transmitting antennas.

Abstract: Disclosed are an apparatus and a method for reducing the coding complexity in an LDPC code used in a digital communication system. In the method, parameters required for coding are determined according to a coding rate and a code length, a seed matrix is generated according to values of the parameters, a plurality of cell matrices are generated according to the values of the parameters, a parity check matrix is generated using the seed matrix and the cell matrix, and information bits are coded from the parity check matrix. The method can be realized by a small memory and a simple shift register and can perform coding even without obtaining a generation matrix, thereby remarkably reducing the complexity of a system.