Abstract: A method for transmitting a PTRS by a transmitting node may include: identifying a time density and a frequency density of PTRS; identifying a first offset based on the frequency density of PTRS and a second offset based on N times the frequency density of PTRS, N being an integer equal to or greater than 2; determining a position of a subcarrier to transmit a first PTRS and a position of a subcarrier to transmit a second PTRS using the first offset and the second offset; determining a resource block (RB) to transmit each of the first PTRS and the second PTRS from resources allocated to a receiving node; configuring a data channel including data, demodulation reference signals (DMRSs) for demodulation of the data, the first PTRS, and the second PTRS; and transmitting the data channel to the receiving node.

Abstract: An operation method of a receiving apparatus may comprise: receiving an N-th data block belonging to a frame including a plurality of data blocks from a transmitting apparatus, each of the plurality of data blocks including a data period and a UW period; storing a first UW received in a UW period of the N-th data block in a buffer; receiving an (N+1)-th data block belonging to the frame from the transmitting apparatus; estimating a phase noise in a time domain by combining the first UW with a second UW received in a UW period of the (N+1)-th data block; and applying time-domain compensation according to the estimated phase noise to the (N+1)-th data block, and demodulating data of the (N+1)-th data block, wherein the first UW and the second UW are configured with a same sequence.

Abstract: An operation method of a receiving apparatus may comprise: receiving an N-th data block belonging to a frame including a plurality of data blocks from a transmitting apparatus, each of the plurality of data blocks including a data period and a UW period; storing a first UW received in a UW period of the N-th data block in a buffer; receiving an (N+1)-th data block belonging to the frame from the transmitting apparatus; estimating a phase noise in a time domain by combining the first UW with a second UW received in a UW period of the (N+1)-th data block; and applying time-domain compensation according to the estimated phase noise to the (N+1)-th data block, and demodulating data of the (N+1)-th data block, wherein the first UW and the second UW are configured with a same sequence.

Abstract: The exemplary embodiment of the present invention provides a beam selecting apparatus of a fixed beam terminal, including: a delay time measuring unit which measures delay times of a plurality of signals received through a plurality of beams; a beam selecting unit which compares a threshold value selected based on the measured delay time and a signal strength of each of the plurality of signals to select a beam; and a switching type beam former which operates the plurality of beams in accordance with the selected beam.

Abstract: Disclosed herein are an apparatus and a method for receiving uplink data to determine whether to use a reception beam group in reception of the uplink data on the basis of a preamble for a random access or a CQI included in a feedback.

Abstract: The present invention relates to a data transmitting method using a bandwidth request channel and a user terminal and a base station conducting the same. The present invention provides a communication method by a user terminal which transmits data to a base station via a bandwidth request channel, including: generating a preamble for bandwidth request; determining whether a message for the bandwidth request is generated; generating a first signal value to be operated with the preamble when it is determined that the message is generated and generating a second signal value to be operated with the preamble when it is determined that the message is not generated; operating the preamble with the generated first signal value or second signal value; and transmitting a signal including the operated preamble to the base station, thereby reducing overhead occurring when the bandwidth request information is demodulated.

Abstract: The exemplary embodiment of the present invention provides a beam selecting apparatus of a fixed beam terminal, including: a delay time measuring unit which measures delay times of a plurality of signals received through a plurality of beams; a beam selecting unit which compares a threshold value selected based on the measured delay time and a signal strength of each of the plurality of signals to select a beam; and a switching type beam former which operates the plurality of beams in accordance with the selected beam.

Abstract: The present invention relates to a signal processing apparatus and method of a basestation. The apparatus according to the present invention includes a plurality of first processing units which allocates transmission data to a predetermined frequency band and transmits a transmission signal in which control information is allocated to a guard band in the predetermined frequency band; a plurality of second processing units which extracts the control information from the guard band in the predetermined frequency band for a reception signal to perform a corresponding operation and extracts the transmission data from the predetermined frequency band to transmit the transmission data through the antenna; and an optical transmitting unit which combines a plurality of transmission signals received from the plurality of first processing units into one signal to transmit the signal to the plurality of second processing units through the optical cable.

Abstract: The present invention relates to a data transmitting method using a bandwidth request channel and a user terminal and a base station conducting the same. The present invention provides a communication method by a user terminal which transmits data to a base station via a bandwidth request channel, including: generating a preamble for bandwidth request; determining whether a message for the bandwidth request is generated; generating a first signal value to be operated with the preamble when it is determined that the message is generated and generating a second signal value to be operated with the preamble when it is determined that the message is not generated; operating the preamble with the generated first signal value or second signal value; and transmitting a signal including the operated preamble to the base station, thereby reducing overhead occurring when the bandwidth request information is demodulated.

Abstract: There is provided a method for acquiring and modifying uplink and downlink synchronization, by which, if there is a possibility of ISI occurring due to incorrect downlink synchronization of a terminal with a base station, the terminal receives a ranging response from the base station, modifies incorrect downlink synchronization, and acquires uplink synchronization in accordance with modified downlink synchronization. The method for acquiring and modifying uplink and downlink synchronization efficiently prevents, in a cooperative communication network, discrepancy in signal transmission synchronization between the base stations, excessive attenuation of a transmitted signal, or a delay caused by a difference in reflection paths.

Abstract: Provided are a signal detector for an uplink control channel and a time error correction method capable of simply correcting time errors, which occur during adjustment of a starting point of an FFT of an uplink control channel signal, by use of differential demodulation and thus improving the signal detection performance of an uplink control channel.

Abstract: A data processing method, an equalizer, and a receiver in a wireless communication system including a relay station are provided. The data processing method includes: receiving a base station signal from a base station; receiving a relay station signal from a relay station; determining a propagation delay between the base station signal and the relay station signal; generating an equalizing signal in which interference generated between the base station signal and the relay station signal is alleviated in consideration of the propagation delay; and recovering information bits transmitted by the base station from the equalizing signal. According to an exemplary embodiment of the present invention, it is possible to alleviate performance deterioration due to an interference problem generated in a relay system.

Abstract: There is provided a method and apparatus for estimating a signal to noise ratio (SNR) in a wireless communication system. The apparatus selects a preamble signal for each of a plurality of sectors from a reception signal experienced by fast Fourier transform (FFT), outputs a correlation signal by performing a correlation between the preamble signal for each sector and a preamble reference signal, estimates power of the reception signal and noise power for each sector based on the correlation signal, selects a minimum value from among the noise powers for the sectors, outputs a net power for each sector by subtracting the minimum value from the power of the reception signal for each sector, and calculates the SNR by dividing the net power for each sector by the minimum value.

Abstract: Disclosed is a method and apparatus for composing a received symbol signal modulated with a bit reflected Gray code into bit information. According to an embodiment of the present invention, a positive integer of the received symbol signal having bits is assigned according to the Gray mapping rule, and a sign is determined. A value that is indicative of an arrangement of the bits constituting the received symbol signal is calculated. A boundary value in at least one bit group consisting of the bits constituting the received symbol signal is acquired, and a difference from an absolute value of the received symbol signal is calculated. The received symbol signal is converted into information per bit using a value of the received symbol signal based on the positive integer and the determined sign, the value that is indicative of the bit arrangement, and the difference from the absolute value.

Abstract: The present invention relates to a digital clipping method for reducing a high peak-to-average power ratio (PAPR) of a transmission signal in a transmitter of an orthogonal frequency division multiplexing access (OFDMA) system. In the method, a) the transmission signal to be digitally clipped is divided into real and imaginary parts, b) magnitudes of the real and imaginary part signals are divided into a plurality clipping levels, and c) the transmission signal is respectively clipped by comparing the real and imaginary part signals with the plurality of clipping levels while allowing phase errors. In c), a plurality of comparators is used to respectively compare the real and imaginary parts of the complex number transmission signal with the plurality of clipping levels.

Abstract: There is provided a method and apparatus for estimating a signal to noise ratio (SNR) in a wireless communication system. The apparatus selects a preamble signal for each of a plurality of sectors from a reception signal experienced by fast Fourier transform (FFT), outputs a correlation signal by performing a correlation between the preamble signal for each sector and a preamble reference signal, estimates power of the reception signal and noise power for each sector based on the correlation signal, selects a minimum value from among the noise powers for the sectors, outputs a net power for each sector by subtracting the minimum value from the power of the reception signal for each sector, and calculates the SNR by dividing the net power for each sector by the minimum value.

Abstract: A data processing method, an equalizer, and a receiver in a wireless communication system including a relay station are provided. The data processing method includes: receiving a base station signal from a base station; receiving a relay station signal from a relay station; determining a propagation delay between the base station signal and the relay station signal; generating an equalizing signal in which interference generated between the base station signal and the relay station signal is alleviated in consideration of the propagation delay; and recovering information bits transmitted by the base station from the equalizing signal. According to an exemplary embodiment of the present invention, it is possible to alleviate performance deterioration due to an interference problem generated in a relay system.

Abstract: Disclosed herein is a base station that extracts a ranging channel signal from a received signal partially correlates each of a plurality of ranging channel signals and each of ranging codes according to ranging modes, and selects a ranging channel signal greater than a first threshold value, the plurality of ranging channel signals being signals according to plurality of time delays of a ranging channel signal. In addition, the base station correlates each of the selected ranging channel signal and each of corresponding ranging code, selects a ranging channel signal having the maximum correlation value, and estimates receiving power by using a time delay corresponding to the selected ranging channel signal.

Abstract: Disclosed herein are a method and an apparatus for transmitting a downlink control signal in a wireless communication system. The apparatus for transmitting a downlink control signal includes: a preamble symbol generator generating preamble orthogonal frequency division multiplexing (OFDM) symbols based on a first pilot pattern among pilot patterns for each of the plurality of transmit antennas; a midamble symbol generator generating midamble OFDM symbols based a second pilot pattern excluding the first pilot pattern from the pilot patterns for each of the plurality of transmit antennas; an IFFT unit performing inverse fast Fourier transform (IFFT) for each transmit antenna on the preamble OFDM symbol and the midamble OFDM symbol; and a plurality of transmit antennas transmitting the preamble OFDM symbols and the midamble OFDM symbols.

Abstract: Disclosed is a method of detecting signals at a receiver of a communication system with a multiple input multiple output antenna. With the signal detection method, a square of the distance between a received signal vector and a channel status-considered transmission symbol vector is calculated first, and the square of the distance is then classified into first and second components. The first component is minimized to calculate a plurality of first soft symbol estimates. A solution set of the first component is calculated on the basis of the plurality of first soft symbol estimates. The second component is minimized to calculate a plurality of second soft symbol estimates. A solution set of the second component is calculated on the basis of the plurality of second soft symbol estimates. A final solution set is calculated by doing the sum of the first component solution set and the second component solution.