Abstract: Provided is an apparatus and method for transmitting and receiving data. The method includes respectively estimating a carrier frequency offset (CFO) of data packets transmitted during a transmit opportunity (TXOP) period by a unit of a packet; calculating an average CFO of the estimated CFOs estimated during a window period for the data packets; and compensating an estimated CFO of a predetermined data packet to one of the estimated CFO of the predetermined data packet and the average CFO, and restoring the predetermined data packet.

Abstract: A method for automatically detecting a packet mode in a wireless communication system supporting a multiple transmission mode includes: acquiring at least one of data rate information, packet length information and channel bandwidth information from a transmitted frame; and determining the packet mode on the basis of the phase rotation check result of a symbol transmitted after a signal field signal and at least one of the data rate information, the packet length information and the channel bandwidth information acquired from the transmitted frame.

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: Provided are a preamble structure and a channel estimation algorithm thereof. A communication method for a transmitter for channel estimation in a Multiple Input Multiple Output (MIMO) wireless communication system having N receiving antennas, includes generating a preamble interval having a short training field that includes a predetermined pattern iterated N times on a time domain and is used for compensating for a carrier frequency offset, and transmitting a packet having the preamble interval.

Abstract: A communication method based on an access point (AP) in a radio communication system is provided. The method includes: acquiring positional information regarding at least one station (STA) and at least one adjacent AP; acquiring interference information from the at least one adjacent AP; determining whether to move based on the positional information and the interference information; determining a position to move based on the positional information and the interference information when determining to move; moving to the position to move; and providing communication services to a subscribed STA at the position.

Abstract: Provided is an apparatus and method for detecting reception signal symbol synchronization in a wireless communication system. The method, includes: calculating a channel power value in each of multiple antennas; selecting and averaging at least 2 channel power values; compensating carrier frequency offset for an average value; and determining a symbol boundary of a reception signal according to the size of the average value compensating the carrier frequency offset.

Abstract: Provided are a transmitter and receiver for a high throughput wireless communication system using a multiple antenna, a method thereof, and a digital intermediate frequency (DIF) transmission signal processing method for the same. The transmitter, includes: a baseband transmitting unit for processing a transmission signal by performing a Media Access Control (MAC) protocol process on transmission data and dividing the transmission data into n band signals where n is a predetermined natural number in a physical layer process; a DIF transmitting unit for integrating transmission signals of each band transmitted from the baseband transmitting unit and outputting m channels where m is a predetermined natural number; and a Radio Frequency (RF) transmitting unit for modulating each channel signal transmitted from the DIF transmitting unit into an RF signal and emitting the signal through the multiple antenna.

Abstract: The present invention relates to a method and apparatus for transceiving data. A method in which a transmitting terminal transmits data to a receiving terminal in a MIMO system according to one embodiment of the present invention comprises the following steps: generating a data field containing the data; generating a signal field containing information on the data field; generating a data frame containing the data field and the signal field; and transmitting the data frame to the receiving terminal. According to the present invention, an end of the frame being transmitted is accurately notified to the receiving terminal in a communication system in which the frame is transmitted using MIMO, thereby decoding the frame in a more efficient manner at the receiving terminal.

Abstract: An apparatus for reducing power consumption of a receiver in a high-speed wireless communication system and a control method thereof are provided. The apparatus for processing a signal in a receiver of a wireless communication system includes a carrier sensor configured to sense a carrier used in the wireless communication system, a decoder configured to decode the detected carrier signal to a signal and data, and a controller configured to control supplying power and a clock only to the carrier sensor during carrier sensing, and supplying power and a clock to an overall receiver when a carrier is sensed.

Abstract: A method and apparatus of accessing a channel in a wireless local area network is provided. A destination station receives a request to send (RTS) frame to allocate a network allocation vector from a source station over a first bandwidth and transmits a clear to send (CTS) frame over a second bandwidth to the source station in response to the RTS frame. The second bandwidth is dynamically determined when a first parameter has a predetermined value.

Abstract: A frame format discrimination method in a wireless communication system is provided. The frame format discrimination method includes: calculating a power of an in-phase signal and a power of a quadrature signal in a predetermined section of a frame; comparing the power of the in-phase signal with the power of the quadrature signal; and determining the format of the frame in accordance with the comparison result.

Abstract: Disclosed is an apparatus and method for transmitting data in a wireless communication system. The apparatus for transmitting a packet data in a wireless communication system includes a Media Access Control (MAC) layer for determining the number of preambles to be inserted based on a feed-back reply signal from a receiver, and generating a multi-preamble aggregation packet by inserting the determined number of preambles into packets received from an upper layer and a physical layer for forming the multi-preamble aggregation packet generated in a data processing unit, by using a physical layer packet, and transmitting the formed multi-preamble aggregation packet.

Abstract: A method and apparatus of accessing a channel in a wireless local area network is provided. A destination station receives a request to send (RTS) frame to allocate a network allocation vector from a source station over a first bandwidth and transmits a clear to send (CTS) frame over a second bandwidth to the source station in response to the RTS frame. The second bandwidth is dynamically determined when a first parameter has a predetermined value.

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: The present invention relates to a method and apparatus for transceiving data. A method in which a transmitting terminal transmits data to a receiving terminal in a MIMO system according to one embodiment of the present invention comprises the following steps: generating a data field containing the data; generating a signal field containing information on the data field; generating a data frame containing the data field and the signal field; and transmitting the data frame to the receiving terminal. According to the present invention, an end of the frame being transmitted is accurately notified to the receiving terminal in a communication system in which the frame is transmitted using MIMO, thereby decoding the frame in a more efficient manner at the receiving terminal.

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: 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: Provided are a receiving apparatus for a multiple input multiple output (MIMO) system and a method thereof. The receiving apparatus includes a QR decomposing unit for calculating a single (Q) matrix vector and an upper triangle (R) matrix vector for a receiving signal vector; a first symbol estimation unit for estimating predetermined symbols using the calculated Q matrix vector and R matrix vector; a log likelihood ratio (LLR) calculating unit for calculating log likelihood ratios of unit bits for the estimated symbols; an interference removing unit for receiving a decoded signal that is decided using the calculated log likelihood ratios and removing interference from the receiving signal vector; and a second symbol estimation unit for linearly estimating remaining symbols for the interference removed signal.

Abstract: Provided are a system and method for providing a wireless network service to a user terminal free of charge, by providing a doorway page for exposing an advertisement on the user terminal provided with the wireless network service through an access point. Accordingly, the user terminal may be provided with the wireless network service free of charge, other than the cost of viewing the advertisement exposed on the doorway page. An advertiser and a proprietor may expose the advertisement at the cost of providing the free wireless network service.