Abstract: An apparatus and method for exchanging frequency bands used by a plurality of base stations are provided. A base station for exchanging frequency bands includes a receiving unit to receive first quiet time duration information of an adjacent base station, a frequency band measuring unit to determine first frequency band measuring information with respect to a first frequency band used by the adjacent base station based on the first quiet time duration information, a frequency band exchange-determining unit to determine whether to exchange frequency bands with each other based on the first frequency band measuring information, and a transmitting unit to transmit data to a terminal using the first frequency band according to the determined result.

Abstract: A method quickly resuming a downlink service in a hard handover in a cellular mobile communication system. To provide the fast downlink service to an MS during a hard handover from an OBS to an NBS, the NBS receives handover user information from the OBS, and generates an MS temporary ID using the handover user information to identify the MS. If user data is generated for the MS before a connection is established for traffic transmission between the MS and the NBS, the NBS transmits the user data to the MS on an HCCH using the MS temporary ID.

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: A cognitive radio communication device and method are provided. The cognitive radio communication device includes a reception unit to receive reference signals from a first communication device, a frequency division unit to divide operating frequency bands of the first communication device into a plurality of sub frequency bands, a first sensing unit to sense each of the plurality of sub frequency bands using the reference signals to estimate whether the first communication device uses each of the plurality of sub frequency bands, and to determine an unused frequency band group including at least one sub frequency band not used by the first communication device based on the estimated result, and a transmission unit to transmit data to a second communication device using the sub frequency band included in the unused frequency band group.

Abstract: A mobile system and a base station system for effectively using a licensed spectrum and a shared spectrum are provided. The mobile system includes: an initialization unit to initialize transmitting and receiving of data using at least one of the licensed spectrum and the shared spectrum; a sensing unit to sense a spectrum for transmitting and receiving of the data via the at least one spectrum; and a transceiver to transmit and receive the data via the sensed spectrum.

Abstract: A technology that can adaptively control an access mode according to a shared band or an unlicensed band used by an adjacent communication system. An access mode controlling apparatus includes a band recognition unit to recognize a usage rate of an unlicensed band or a shared band that is used by an adjacent communication system of a target communication system; a mode determination unit to determine, as an access mode, any one of a contention access mode and a contention-free access mode, based on the usage rate of the unlicensed band or the shared band; and an information transmitter to transmit mode information associated with the determined access mode to member nodes or a base station of the target communication system.

Abstract: A mobile station which connects to a base station having a plurality of relays belonging thereto is provided. The mobile station includes a receiving unit which receives a first preamble signal from a first relay and receives a second preamble signal from a second relay, the first relay belonging to a first cluster including an N1 number of relays and the second relay belonging to a second cluster including an N2 number of relays, a control unit which selects the first cluster as an access cluster to connect to the base station, based on the first preamble signal and the second preamble signal, and a transmission unit which transmits an access request message to the first relay, wherein the access request message is transmitted to the base station via the first relay.

Abstract: A method of scheduling uplink resources in a wireless communication system supporting VoIP service is provided. A BS allocates an identical amount of the resource continuously until an uplink data rate is changed by an SS's request for a data rate change. When the data rate is changed, the SS reports this event to the BS so that the BS allocates an amount of resource corresponding to the requested data rate.

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: An operation method of a radio communication station is provided. The operation method of a radio communication station, the operation method including: transmitting a basic pilot signal to at least one terminal located in a coverage of a preoccupied system; and transmitting a cognitive radio (CR) pilot signal.

Abstract: A mini base station connectable with the Internet including a frequency recognition unit to recognize a frequency band of an external signal transmitted from a cellular base station; and an operation frequency determination unit to determine an operation frequency band according to interference generated with the cellular base station based on the recognized frequency band of the external signal.

Abstract: A method of setting a packet transmission path in a wireless communication network and a network apparatus using the same are provided. A method of setting a packet transmission path includes setting N?1 routing regions including at least one node between a source node and a destination node based on a predetermined N number of hops, N denoting an integer greater than or equal to two, and determining a node in each of the routing regions as a relay node based on a channel gain.

Abstract: A portable device for processing a multimedia signal is provided. The portable device includes: a signal receiver to receive a multimedia signal from a mobile terminal, the multimedia signal being received in the mobile terminal from a service providing server; a decoding-related information generation unit to generate decoding-related information which is related to at least one of a codec and a resolution; a decoder to decode the multimedia signal according to the decoding-related information, and to generate multimedia information; and a multimedia information transmitter to transmit the multimedia information to an external display device.

Abstract: A terminal apparatus for forwarding/sharing a data service is provided.

Abstract: A space frequency block code signal relaying system is provided. The space frequency block code signal relaying system includes a signal detecting unit which receives, via a radio channel, a source signal sent from a source station and detects the received signal; a relay signal generation unit which generates a relay signal corresponding with the source signal transmitted from the source station to a destination node based on the received signal, the source signal and the relay signal being signals encoded in a Space Frequency Block Code (SFBC) scheme; and a signal transmitting unit which transmits the relay signal to the destination node.

Abstract: A method and apparatus for compensating a distortion due to a clipped amplitude when an amplitude of a signal is clipped to reduce a peak to average power ratio (PAPR) in a wireless communication system using an orthogonal frequency division multiplexing (OFDM) scheme and a transmit diversity method using an orthogonal coding. A wireless data transmission apparatus which transmits a data stream via a plurality of antennas, the apparatus including: a coding unit which Space-Time block codes a first data stream into a plurality of second data streams, the plurality of second data streams being orthogonal to each other; an inverse Fourier transform unit which performs an inverse Fourier transform of each of the Space-Time block coded second data stream and generates a plurality of time domain signals; and a plurality of amplitude clipping units which clips an amplitude of each of the plurality of generated time domain signals.

Abstract: A method of determining an optimal transmission mode and a data frame structure for determining an optimal transmission mode in a data transmission system using a relay, are provided. Any one of a base station, a relay, and a mobile station determines an optimal transmission mode from among a plurality of transmission modes, and the base station transmits the determined optimal transmission mode by enabling the determined optimal transmission mode to be included in the system information duration of the data frame, so that the overall relay system can transmit data according to the optimal transmission mode.

Abstract: An HARQ method for guaranteeing a QoS in a wireless communication system is provided. In a transmitting apparatus using a HARQ for transmitting packet data in a wireless communication system, a retransmission controller determines the size of redundancy information for correcting transmission errors in packet data, and a transmitter transmits the redundancy information of the determined size upon request for a retransmission of the packet data. Transmission of redundancy information of a variable size at each retransmission satisfies the QoS required for each user, maximizes a data throughput, and allows for the efficient reception of an ACK or a NACK for the redundancy information.

Abstract: A system and method for transmitting resource allocation information in a wireless communication system is provided. A transmitter transmits resource allocation information mapped to a current time interval in a first region to a receiver, and transmits resource allocation information mapped to a next time interval in a second region. When receiving the resource allocation information of the second region, the receiver notifies the transmitter whether the resource allocation information has been received. The transmitter receives notification that the resource allocation information of the second region has been received and transmits resource allocation information mapped to a subsequent time interval in the second region.

Abstract: A method is provided for transmitting/receiving data in a communication system. The method includes allocating, by a Base Station (BS), bands unused in a band Adaptive-Modulation-and-Coding (band AMC) scheme to Mobile Stations (MSs) of a diversity scheme, and transmitting data by adaptively using the band AMC scheme and the diversity scheme; and identifying, by an MS, resources allocated to the MS, and transmitting data by using either the band AMC scheme or the diversity scheme according to a result of the identifying.