Abstract: Provided is a data transmission system using a vertical layer optimisation technique. A data transmission device predicts the buffer state of a data receiving device by using feedback information of a physical layer, and controls data transmission by referring to the predicted buffer state. The data transmission device can control the transmission of first data and second data such that the buffer state of the receiving device is within a preset range.

Abstract: Provided are a distributed repeater for repeating output signals identical to input signals through a channel different from that of main transmitter signals but identical to channels of other distributed repeaters, and a distributed repeating method thereof. The distributed repeater includes: a pre-processing unit configured to receive a radio frequency (RF) signal transmitted from an external device and demodulate the RF signal into a baseband signal; an equalizer configured to equalize the baseband signal to correct a distortion occurring on a transmission channel; an identification signal generation and insertion unit configured to generate an identification signal for identification of the distributed repeater and network conditioning, and insert the identification signal in the equalized baseband signal; and a post-processing unit configured to convert the baseband signal from the identification signal generation and insertion unit into an RF signal, and send the RF signal.

Abstract: A method and apparatus for processing enhanced media data in a Digital Multimedia Broadcasting (DMB) system is provided. The apparatus for processing enhanced media data includes: a base layer processing unit configured to multiplex an elementary stream of a base layer and perform channel encoding for the multiplexed elementary stream of the base layer; an enhancement layer processing unit configured to synchronize an elementary stream of an enhancement layer with the elementary stream of the base layer and thereby multiplex the elementary stream of the enhancement layer and process the elementary stream of the enhancement layer to be transmittable via at least one of a plurality of transmission channels; and a synchronizer configured to provide the enhancement layer processing unit with synchronization information that is used for synchronizing the elementary stream of the enhancement layer with the elementary stream of the base layer.

Abstract: Provided is an apparatus and method for estimating inverse channel of a repeater's receiving channel, which ensures stability and causality by generating a time-domain filter coefficient having information on an inverse channel of repeater's receiving channel from a signal transmitted from a main transmitter or another repeater. The apparatus includes: a channel estimator for estimating a channel established by a transmission path from a received signal; an inverse minimum phase filter coefficient generator for generating inverse channel of a minimum phase channel from the estimated channel, and converting the inverse channel of the minimum phase channel into a time-domain filter coefficient; an inverse group delay filter coefficient generator for generating a time-domain filter coefficient by using the estimated channel and the minimum phase channel; and a combiner for generating an inverse channel of a receiving channel in a time domain by combining the filter coefficient and the filter coefficient.

Abstract: A data transmitting apparatus generates a plurality of modulation data symbols by performing symbol mapping of input data, converts and angle-modulates the plurality of modulation data symbols from a frequency domain to a real number signal of a time domain, and circular-shifts and transmits the angle-modulated signal from a signal of a frequency domain.

Abstract: A repeater converts a frequency of a received signal based on a local oscillating frequency and transmits a transmitting signal of a frequency that is different from the frequency of the received signal. Here, the local oscillating frequency includes a local oscillating error that may be different in a plurality of repeaters. Accordingly, the repeater cancels the local oscillating frequency error itself in a frequency conversion so that transmitting frequencies between the plurality of repeaters may be identical.

Abstract: Disclosed are payload formatting and deformatting methods for burst data loss recovery. The payload formatting method according to an embodiment of the present invention includes: generating an XOR operation packet by performing an XOR operation on the basis of a base layer packet and any one of enhancement layer packets of a group of pictures (GoP), the GoP including the base layer packet and the enhancement layer packets; and adding the XOR operation packet to the GoP.

Abstract: A method and an apparatus for providing video service according to example embodiments of the present invention are disclosed. The method for providing video service according to one example embodiment of the present invention comprises determining based on a predetermined reference whether it is necessary to set multiple bearers to provide the video service for a terminal, and when it is determined necessary to set the multiple bearers, setting an additional bearer, dividing a video source stream into a first stream and a second stream, assigning the first and second streams to a default bearer and the additional bearer, respectively, and transmitting the first and second streams to the terminal.

Abstract: Provided is an on-channel repeater capable of removing feedback signals based on pilot partitioning, which can efficiently remove a feedback signal by quickly coping with even a situation in which a feedback channel changes rapidly, by reducing a filter-coefficient update interval, i.e., increasing the number of times of filter-coefficient creation, through pilot partitioning, and a method thereof. The on-channel repeater includes: a receiver for receiving a signal; a subtractor for subtracting a replica of a feedback signal from the signal received in the receiver to remove the feedback signal; a replica creator for creating a filter coefficient using pilot partitioning, creating a replica of the feedback signal using the created filter coefficient, and feeding back the created replica to the subtractor; and a transmitter for transmitting an output signal of the subtractor.

Abstract: A repeater having different input and output frequencies converts a signal received with the input frequency to a first intermediate frequency signal based on a local oscillating frequency for intermediate frequency conversion, and converts the first intermediate frequency signal to a second intermediate frequency signal by performing digital processing on the first intermediate frequency signal. Then, the repeater generates a first frequency tone signal that corresponds to a difference between the input and output frequencies, and generates a second frequency tone signal from the local oscillating frequency for intermediate frequency conversion and the first frequency tone signal. The repeater up-converts the second intermediate frequency signal to the output frequency based on the second frequency tone signal, and transmits the signal.

Abstract: A data transmitting apparatus performs symbol mapping on each of first and second input data to generate a plurality of first and second modulation data symbols, performs inverse fast Fourier transform (IFFT) on the plurality of first and second modulation data symbols to convert the same into first and second real signals of a time domain from a frequency domain, angle-modulates the first and second real signals, and transmits the same to a data receiving apparatus. Thus, a peak-to-average power ratio (PAPR) can be lowered, while the same data transfer amount as that of the general OFDM data transmitting apparatus is maintained.

Abstract: Disclosed are data transmission/reception apparatus and method that may be applied to a case where additional data is to be transmitted in a CE-OFDM modulation/demodulation scheme that satisfies an OFDM feature which is robust against multipath fading and simultaneously has a feature that amplitude is constant. Service channel information, modulation parameter information of a physical layer, and the like, may be transmitted by using an additionally secured information channel. If using this, a service search time may be saved, and power of a receiver may be reduced.

Abstract: Provided is an on-channel repeater, which includes a receiver for receiving radio frequency (RF) signals; a subtractor for subtracting replica from the RF signals to thereby produce output signals of the subtractor; a repeating process unit for performing a repeating process onto the output signals of the subtractor; and a replica generator for calculating replica based on the output signals of the subtractor and the signals obtained after repeating process performed thereon and feeding the replica back to the subtractor.

Abstract: Provided are a coordinated multipoint transmission and reception method and a coordinated multipoint transmission and reception system for performing the same. In the coordinated multipoint transmission and reception method, a first point and a second point participating in the coordinated multipoint transmission exchange resource allocation information for coordinated multipoint transmission, allocate resources for coordinated multipoint transmission not to overlap each other based on the exchanged resource allocation information, and perform the coordinated multipoint transmission using the allocated resources. Accordingly, use efficiency of radio resources can be improved and embodying complexity can be reduced.

Abstract: Provided is a method of retransmitting and receiving a packet in heterogeneous network environment. A terminal and a relay base station receive a packet transmitted from a macro base station, and the relay base station informs the terminal of whether the packet is successively received or not. When the packet fails to be received, the terminal is configured to receive the erroneous packet again from at least one of the macro base station and the relay base station. The macro base station and the relay base station may be configured to retransmit the packet through joint processing JP) transmission, and the terminal may be configured to receive the JP transmission. Thus, the method allows the m optimization of a HARQ process and scheduling scheme to efficiently utilize a relay and radio resources, thereby leading to a maximum capacity and quality of wireless network.

Abstract: Provided are an apparatus and method for transmitting multimedia data in a wireless network. The apparatus and method receive multimedia data classified into at least one layer, and set different radio bearer channels for the respective at least one multimedia layer. Here, a service quality parameter is differentially applied to the respective set radio bearer channels, so that end-to-end quality of service (QoS) improvement is maximized.

Abstract: Provided are a method of packetizing encoded symbols and an apparatus using the same. The method includes an encoded symbol and target packet selection step of deciding a first source symbol and selecting an unpacketized first encoded symbol and a target packet into which the unpacketized first encoded symbol is inserted if there is the unpacketized first encoded symbol of at least one first encoded symbol, which is an encoded symbol of the first source symbol generated using an AND-OR tree structure, and a packetization step of generating a second source symbol based on at least one unpacketized first encoded symbol by use of the AND-OR tree structure, generating at least one second encoded symbol based on the second source symbol by use of the AND-OR tree structure, and packetizing at least one of second encoded symbols into the target packet along with the first encoded symbol.

Abstract: Provided are an apparatus and method for selecting an optimal signal using auxiliary equalization in a diversity receiver. The optimal signal selecting apparatus includes: a plurality of sync recovery units for extracting sync information from baseband signals, which are candidate signals, except a baseband signal selected as a current optimal signal a plurality of auxiliary equalizers for channel-equalizing the candidate signals based on the extracted sync information; a plurality of SNR measuring units for measuring signal-to-noise ratios (SNRs) of the candidate signals inputted to the auxiliary equalizers and the candidates signals equalized in the auxiliary equalizers; and an optimal signal selector for selecting an optimal candidate signal from the candidate signals by using the extracted sync information and the measured SNRs, and replacing the optimal signal with the optimal candidate signal when reception quality of the current optimal signal is poor.

Abstract: Provided are an on-channel repeater for repeating an output signal the same as an input signal on channel by removing feedback signals caused by low isolation of a transmission/reception antenna by converting a transmitted Radio Frequency (RF) signal into a signal of a predetermined band and subtracting a replica of the feedback signal from the converted signal, and by compensating for channel distortion of a reception signal by estimating an inverse of reception channel from a signal acquired by removing the feedback signal, and an on-channel repeating method.

Abstract: A data transmission apparatus is provided. A symbol mapper performs symbol mapping on information about an optimum key index that instructs a modified Walsh-Hadamard matrix that causes a minimum peak-to-average power ratio and generates a plurality of key symbols. A modified Walsh-Hadamard transformer generates a plurality of modified Walsh-Hadamard-transformed data symbols by performing modified Walsh-Hadamard transform on a plurality of data symbols according to a modified Walsh-Hadamard matrix that an optimum key index instructs. An inverse Fourier transformer generates a plurality of inverse Fourier-transformed symbols by performing inverse Fourier transform on a plurality of key symbols and a plurality of modified Walsh-Hadamard-transformed data symbols. A transmitter transmits a plurality of inverse Fourier-transformed symbols to a channel through at least one antenna.