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: 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: 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: A spatial multiplexing detection device using a MIMO technology comprises a MIMO detector for detecting receive symbols which correspond to symbols transmitted through transmit antennas from receive signals when the transmit data transmitted by the terminal group are received through receive antennas; a terminal identifier for identifying the receive symbols detected by the MIMO detector into symbols which correspond to respective terminals in the terminal group; a symbol demapper for demapping the receive symbols identified by the terminal identifier to binary data which correspond to a modulation method used by the terminal group; and a reverse data processor for performing deinterleaving, decoding of error correction codes, and descrambling on the binary data demapped by the symbol demapper, and detecting receive data of the respective terminals.

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.

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 for tracking a residual frequency offset for a single carrier-frequency domain equalizer system includes: determining a pilot from the data and known pilot data, adding the determined pilot to the leading part of the data, copying a part of the frame of the data after a block and adding it before the block, and generating a preamble to construct one frame; eliminating a cyclic prefix, processing signals per an FFT block, extracting the preamble, and performing an initial channel estimation; updating a channel estimation, performing channel compensation, receiving a pilot, calculating an average phase of all the pilots in one FFT block, updating the channel estimation, performing an IFFT operation, extracting data, and recovering the original digital signal from the data.

Abstract: A method for tracking carrier frequency and sampling frequency offsets in an OFDM wireless communication system comprises: (a) detecting data received from the transmitter using a first signal, and tracking a phase offset caused by the carrier frequency offset using the detected received data; (b) detecting the data received from the transmitter using the first signal, and tracking the phase offset caused by the sampling frequency offset using the detected received data; (c) compensating for the phase offset caused by the carrier frequency offset between the transmitter and the receiver according to the phase offset tracked in (a); and (d) compensating for the phase offset caused by the sampling frequency offset between the transmitter and the receiver according to the phase offset tracked in (b).

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: The present invention relates to a transmitting apparatus of a wireless communication system, and a method thereof. The transmitting apparatus monitors receiving of response data for data that has been transmitted to a receiving end, and sets a first parameter for counting successful receipts according to receiving on the response data. The transmitting apparatus demodulates the response data and extracts the number of demodulated data that satisfies a first set value. Subsequently, it is determined whether the first parameter satisfies a second set value and the number of demodulated data satisfies a predetermined ratio of a referential amount of packets. According to the present invention, an efficient transmission mode for a channel state can be provided with reference to an extracted number of soft-decision data from response data received at a receiving end. In addition, a transmission mode can be determined by using only response data according to the present invention.

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: 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. According to the present invention, first OFDM modulation is performed for an even-numbered time, and second OFDM modulation is performed by changing subcarrier allocation positions of first OFDM modulated symbols for an odd-numbered time. In addition, a transmitting frame including a plurality of signal fields according to the first and second OFDM modulation is transmitted. The receiving system determines a format configuration of the received frame to determine whether a signal field is repeatedly generated in the frame. When it is determined that the signal field is not repeatedly generated, corresponding demodulation is performed.

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.

Abstract: A spatial multiplexing detection device using a MIMO technology comprises a MIMO detector for detecting receive symbols which correspond to symbols transmitted through transmit antennas from receive signals when the transmit data transmitted by the terminal group are received through receive antennas; a terminal identifier for identifying the receive symbols detected by the MIMO detector into symbols which correspond to respective terminals in the terminal group; a symbol demapper for demapping the receive symbols identified by the terminal identifier to binary data which correspond to a modulation method used by the terminal group; and a reverse data processor for performing deinterleaving, decoding of error correction codes, and descrambling on the binary data demapped by the symbol demapper, and detecting receive data of the respective terminals.

Abstract: A method for tracking carrier frequency and sampling frequency offsets in an OFDM wireless communication system comprises: (a) detecting data received from the transmitter using a first signal, and tracking a phase offset caused by the carrier frequency offset using the detected received data; (b) detecting the data received from the transmitter using the first signal, and tracking the phase offset caused by the sampling frequency offset using the detected received data; (c) compensating for the phase offset caused by the carrier frequency offset between the transmitter and the receiver according to the phase offset tracked in (a); and (d) compensating for the phase offset caused by the sampling frequency offset between the transmitter and the receiver according to the phase offset tracked in (b).

Abstract: A method for tracking a residual frequency offset for a single carrier-frequency domain equalizer system includes: determining a pilot from the data and known pilot data, adding the determined pilot to the leading part of the data, copying a part of the frame of the data after a block and adding it before the block, and generating a preamble to construct one frame; eliminating a cyclic prefix, processing signals per an FFT block, extracting the preamble, and performing an initial channel estimation; updating a channel estimation, performing channel compensation, receiving a pilot, calculating an average phase of all the pilots in one FFT block, updating the channel estimation, performing an IFFT operation, extracting data, and recovering the original digital signal from the data.