Abstract: A method and apparatus of selecting N metrics among M metrics is provided. The apparatus determines M metrics P(i), where i=1, . . . , M. Each P(i) is represented by B bits. The apparatus determines N metrics among M metrics. The complexity for configuring the circuit is decreased, and the length of the critical path is reduced.

Abstract: The present invention relates to a decoding device and method for a MIMO system. A linear process is applied to a received signal vector by using a channel matrix estimated from the received signal vector and a poly-diagonalized matrix, and a soft decision value is acquired through a trellis decode by using the linear process result. Since the linear preprocess is performed by using the poly-diagonalized matrix, it is possible to receive a MIMO signal having good packet error rate performance and less complexity. Also, since the tail-biting trellis decoding method is used based on the poly-diagonalized matrix that is generated by poly-diagonalizing the effective channel matrix during the process for eliminating the signal interference, the soft decision value for the symbol can be generated with a simple hardwired device and less operation complexity.

Abstract: Provided are apparatus and method for receiving signals in a wireless communication system.

Abstract: A channel sounding method in a wireless local area network (WLAN) system is provided. The method, performed by a transmitter, includes transmitting a null data packet announcement (NDPA) frame to a receiver to initiate a channel sounding procedure; transmitting a null data packet (NDP) to the receiver and receiving a feedback frame. The feedback frame includes a plurality of segment frames and a channel feedback report. The channel feedback report is split into a plurality of feedback segments. Each of the plurality of feedback segments is respectively included in each of the plurality of segment frames. The each of the plurality of segment frames includes a first-segment subfield indicating whether the each of the plurality of feedback segment included is a first segment and a remaining-segment subfield indicating the number of remaining feedback segments.

Abstract: A method and apparatus for transmitting a relay frame in a relay end are provided. The method includes: receiving a relay request frame requesting data transmission to a receive end from a transmit end; transmitting a relay response frame including information on data to be relayed to each of the transmit end and the receive end; receiving the data from the transmit end; and generating a relay frame including the data to transmit the relay frame to the receive end. According to the present invention, the data is transmitted to the receive end positioned outside a transmission coverage of the transmit end, such that a wireless LAN service coverage may be expanded, and an adjacent terminal connected to the receive end is used as the relay end, such that the transmit end that may not be connected directly to the receive end may communicate with the receive end.

Abstract: A method and an apparatus for a transmitter to transmit data in a wireless communication system are provided. This method includes: generating a first signal field including at least one symbol; generating a second signal field configured by repeating at least one symbol of the first signal field; and transmitting a frame including the first signal field, the second signal field, and a data field and a first symbol of the second signal field is modulated through binary phase shift keying (BPSK) and symbols from a second symbol of the second signal field are modulated through Q-BPSK. According to the present invention, a service filed can be extended while maintaining compatibility with a wireless communication system in the related art by transmitting a frame using symbol repetition.

Abstract: Disclosed are a method and apparatus of performing a fast Fourier transform (FFT). The apparatus include a plurality of single-path delay feedback (SDF) butterfly blocks which performs butterfly operations, respectively; a plurality of memories which are connected to the SDF butterfly blocks, respectively; and a controller which controls the plurality of SDF butterfly blocks, wherein the plurality of SDF butterfly blocks are connected in a pipeline structure and thus output from one SDF butterfly block is input to a following SDF butterfly block.

Abstract: Disclosed is a method and receiver for detecting a wireless signal in a wireless local area network (WLAN) system. The receiver includes a radio frequency (RF) unit which receives a wireless signal; an analog/digital converter (ADC) which converts the wireless signal into a digital signal; a fast Fourier transform (FFT) unit which applies FFT to the digital signal; a multiple inputs and multiple outputs (MIMO) detector which performs channel compensation for the FFT applying result; a constellation-demapping unit which constellation-demaps with regard to the channel compensation result; a decoder which decodes the constellation-demapping result; and a high throughput (HT) detector which determines whether the wireless signal is a signal modulated with quadrature binary phase shift keying (Q-BPSK) constellation obtained by rotating binary phase shift keying (BPSK) constellation at an angle of 90 degrees on the basis of the FFT applying result.

Abstract: An apparatus for acquiring synchronization using a signal having repetition patterns is provided. The apparatus includes: a signal reception unit for receiving signal streams transmitted in the repetition patterns, a synchronization point tracking unit for calculating, during one period in which the signal streams are repeated in the repetition patterns, an add-sum of the signal streams, a sub-sum of the signal streams and an add-sub-sum which is a difference between the add-sum and the sub-sum, and for tracking an estimated synchronization point by comparing the sub-sum and the add-sub-sum, and a synchronization acquisition unit for acquiring, based on the estimated synchronization point, a synchronization point by searching for a point where the repetition of some of the signal streams is ended or a point where new signal streams having different characteristics from the signal streams are started.

Abstract: An apparatus for acquiring synchronization in a multi-channel system includes a signal reception unit for receiving information about repetition patterns of signal streams for each channel and receiving the signal streams and data from the channel, an estimated synchronization point tracking unit for determining a estimated synchronization point for the channel from a point of time where the repetition patterns are ended by tracking a period where the signal streams are repeated based on the repetition patterns, and a synchronization acquisition unit for searching, based on the estimated synchronization point related to the channel, for a point where the repetition of the signal stream is ended or a point where new signal streams are started and acquiring a synchronization point based on the point.

Abstract: A wireless apparatus providing wireless LAN services for a transport means is provided. The wireless apparatus includes: a transceiver established to transmit or receive a frame; and a processor functionally connected to the transceiver, wherein the processor is established to generate and process the frame for providing the wireless LAN services, the transceiver includes a plurality of remote antennas, and the plurality of remote antennas are disposed to be spaced away from each other along a moving path of the transport means.

Abstract: The present invention provides a method of a node sending frames in a Cognitive Radio (CR) system. The method of the node includes being allocated a first channel as an operating channel where the node will be operated, sensing one or more candidate channels available as the operating channel of the node, determining whether to extend a frequency bandwidth of the operating channel, in addition to the first channel, based on a result of the sense for the one or more candidate channels, and sending the frames using a frequency bandwidth extended by adding a second channel, newly determined as the operating channel, to the first channel according to the determination.

Abstract: Disclosed is a loop-back apparatus in wireless communication systems, including: an MAC processing unit configured to transmit a user data and a control frame when a loop-back mode is established; a loop-back unit configured to generate a response frame of a receipt for the user data and the control message transmitted from the MAC processing unit and again feedbacks the generated response frame to the MAC processing unit.

Abstract: An apparatus for detecting a packet end point in a wireless communication system includes: a signal reception unit configured to receive a signal from an outside, convert the signal into a baseband signal, perform analog-digital conversion of the baseband signal, and perform a digital front end; a storage unit configured to store an output of the signal reception unit; a frequency offset estimation unit configured to estimate a frequency offset using the output of the storage unit; a frequency offset correction unit configured to compensate for a frequency error using the estimated frequency offset; an offset correlation unit configured to calculate correlation of the frequency offset and a cyclic prefix; an auto-correlation operation unit configured to calculate auto-correlation of the cyclic prefix; and a packet end detection unit configured to check a packet end point using the auto-correlation.

Abstract: Provided are an apparatus and method for compensating for a delay mismatch between an amplitude component signal and a phase component signal. The apparatus includes an amplitude path delay obtainer configured to obtain amplitude-delay information on a delay occurring in a propagation path of an amplitude component signal, a phase path delay obtainer configured to obtain phase-delay information on a delay occurring in a propagation path of a phase component signal, a delay controller configured to calculate and output a difference between the obtained amplitude path delay and the obtained phase path delay, and a variable delayer configured to compensate for a delay by changing a delay value on the basis of the delay difference output from the delay controller.

Abstract: Provided is an apparatus and method for detecting a packet in a Wireless Local Area Network (WLAN) which can reduce a processing time of packet detection based on Orthogonal Frequency Division Multiplexing (OFDM) by detecting a received packet employing symmetry of a short preamble. The packet detecting apparatus includes an autocorrelation average power calculation unit for calculating an absolute value of an autocorrelation average power value obtained by delaying a preamble signal of a received signal by half of a preamble length, an average power calculation unit for calculating an average power value of the received signal, a power ratio calculation unit for calculating a ratio of the average power value to the absolute value of the average power value, and a packet detection unit for detecting the packet by using the power ratio calculated by the power ratio calculation unit.

Abstract: Provided are apparatus and method for transmitting and receiving data for a wireless communication system. The method includes generating a first aggregation packet by controlling the number of preambles or by controlling a size of a packet according to a channel state of a channel formed to at least one reception terminal or according to a state of the reception terminal, and transmitting the first aggregation packet to the reception terminal.

Abstract: A data communication method in a basic service set (BSS) of a wireless communication system using a carrier sense multiple access with collision avoidance (CSMA/CA) protocol includes: performing, by first and second nodes within the BSS, communication within a predetermined first time period; and transmitting, by a third node within the BSS, data to a fourth node within the first time period through a channel which is not used by the other nodes.

Abstract: A phase calculation apparatus using a binary search is provided. The phase calculation apparatus includes a quarter surface preprocessor determining the bigger one between an absolute value of I component data and an absolute value of Q component data as horizontal component data and the smaller one as perpendicular component data, and detecting information on a phase region indicating an mth (m=1 to 8) phase region (the mth phase region is between (m?1) ?/4 and m ?/4 in which the I/Q component data are located; a phase representative value detector detecting phase representative values x corresponding to the horizontal component data and the perpendicular component data; and a quarter surface postprocessor calculating phase values of the I/Q component data based on the detected information about the phase region and the detected phase representative values x. The phase can be calculated using a limited memory, low complexity of calculation and regardless of the number of bits of I/Q component data.

Abstract: The present invention relates to a decoding device and method for a MIMO system. A linear process is applied to a received signal vector by using a channel matrix estimated from the received signal vector and a poly-diagonalized matrix, and a soft decision value is acquired through a trellis decode by using the linear process result. Since the linear preprocess is performed by using the poly-diagonalized matrix, it is possible to receive a MIMO signal having good packet error rate performance and less complexity. Also, since the tail-biting trellis decoding method is used based on the poly-diagonalized matrix that is generated by poly-diagonalizing the effective channel matrix during the process for eliminating the signal interference, the soft decision value for the symbol can be generated with a simple hardwired device and less operation complexity.