Abstract: An apparatus and a method for transmitting a Coexistence Beacon Protocol (CBP) packet in a Cognitive Radio (CR) wireless communication system are provided. In the method for transmitting CBP packet in a transmitter that operates in a scalable Orthogonal Frequency Division Multiple Access (OFDMA) mode, a priority is given to each channel of one or more channels based at least partly upon channel use statuses of two or more neighbor Wireless Regional Area Networks (WRANs). Whether a Quality of Service (QoS) for CBP packet transmission for each channel is met is sequentially determined according to the respective priority. A channel having a highest priority is selected from the one or more channels meeting the QoS as a channel for CBP packet transmission. A CBP packet is transmitted via the selected channel.

Abstract: An operating method and apparatus of a Customer Premise Equipment (CPE) in a Cognitive Radio (CR) wireless communication system and a base station in the CR wireless communications system are provided. The method includes, when receiving a beacon message from a Primary User (PU), transmitting a mode change request message including a signal strength from the PU and a channel number interfering with the PU to a base station, when receiving a mode change reply message from the base station, determining whether a partial Frequency Division Duplex (FDD) scheme is applied, and, when the partial FDD scheme is applied, communicating by receiving a downlink burst in a Time Division Duplex (TDD) channel indicated by the mode change reply message and transmitting an uplink burst in an FDD channel indicated by the mode change reply message.

Abstract: A method and apparatus for sychronizing a Quiet Period (QP) in a Cognitive Radio (CR) system includes receiving QP information based on a channel N from at least one neighbor BS. The method further includes determining whether the channel N is an in-band channel. If the channel N is the in-band channel, QP scheduling is performed according to the received QP information based on the channel N.

Abstract: A base station includes an apparatus and a method for exchanging frequency channel resources between base stations in a Cognitive Radio (CR) based communication system. A requesting Base Station (BS), which requests channel exchange a neighboring BS, receives a channel advertisement message from a neighboring BS and sends a channel exchange request message to the neighboring BS. The channel exchange request message includes at least one of a neighbor BS Identifier (ID), a requesting BS ID, channel information for the channel exchange at the requesting BS, and channel information exchangeable at the neighboring BS. The requesting BS receives a channel exchange response message from the neighboring BS in response to the channel exchange request message, determines whether to execute a channel exchange process to the neighboring BS based on information in the received channel exchange response message, and sends a channel exchange reply message indicative of the determination result.

Abstract: A method and apparatus for switching operational modes in a Cognitive Radio (CR) system are provided. A method for switching between a normal operation mode and a coexistence operation mode in a CR system includes occupying at least one channel in the normal operation mode, when there is no channel to be occupied, selecting at least one channel for the coexistence operation mode, and occupying available frames among frames of the selected at least one channel in the coexistence operation mode.

Abstract: An operating method of a source Base Station (BS) for inter-frame sharing in a Cognitive Radio (CR) system includes generating a first random number for a frame contention; requesting the frame contention to one or more destination BSs by carrying the first random number; receiving responses for the frame contention request from the one or more destination BSs; and when positive responses for the frame contention request are received from all of the one or more destination BSs, occupying one or more requested contention frames.

Abstract: A frequency overlay communication system that includes a first communication system for performing communication using a first frequency band being a preset bandwidth; and a second communication system for performing communication using a second frequency band being a second preset bandwidth, wherein the second frequency band includes the first frequency band.

Abstract: A method of and apparatus for operating a Coexistence Beacon Protocol (CBP) packet transmitter in a Cognitive Radio (CR)-based wireless communication system is provided. The method includes, identifying a Self-Coexistence Window (SCW) regular pattern of neighbor Wireless Regional Area Networks (WRANs), if vacant SCW slots are not periodically occurring, selecting a WRAN as a contender among the neighbor WRANs, performing a contention for transmitting the CBP packet with the contender within SCW slots that are occupied by the WRAN, and configuring an SCW usage pattern so that an SCW usage period of the CBP packet sender is double that of an SCW usage period of the contender when winning in the contention.

Abstract: A frame structure, a method, and an apparatus for inter-frame resource sharing in a Cognitive Ratio (CR) communication system are provided. An apparatus for sharing a channel in an environment where a plurality of CR communication systems coexist, constitutes a Superframe Control Header (SCH), in one superframe, that includes a frame allocation MAP for frame information allocated to a Base Station (BS), with respect to each BS, and transmits and receives the SCH at the start frame of the frames allocated to the BSs.

Abstract: A method of operating a Data Base (DB) server for storing spectrum condition information on a licensed system in a Cognitive Radio (CR)-based wireless communication system and a CR-based wireless communication system are provided. The method includes determining changes in the spectrum condition information on the licensed system, recalculating maximum Equivalent Isotropically Radiated Power (EIRP) allowed for each channel of CR-based devices registered in a list, and transmitting information regarding the recalculated maximum allowed EIRP.

Abstract: Provided are an apparatus and a method for transmitting a CBP packet for communication information sharing between base stations in a CR-based wireless communication system. In the method, a CBP packet including a CBP identifier is transmitted to a base station of adjacent cells via one SCW slot. A CBP identifier list for successfully received CBP packets is received from the base station of the adjacent cells. When the CBP identifier is included in the CBP identifier list, the SCW slot is occupied.

Abstract: An apparatus and a method for selecting a candidate channel to change an operating channel so as to minimize effect of interference in a wireless communication system using a Cognitive Radio (CR) function are provided. The method includes confirming an operating channel of at least one neighbor cell and candidate channel set to a third group by the neighbor cell; setting a candidate channel used as the operating channel of the neighbor cell among at least one candidate channels changeable to the operating channel, to a third group of lowest priority; setting candidate channels set to the third group of the neighbor cell among candidate channels not set to the third group, to a second group; and setting candidate channels set to neither the second group nor the third group, to a first group of highest priority.

Abstract: A channel interleaving method and apparatus in a communication system using a low density parity check (LDPC) code. Upon receipt of information data bits, an encoder encodes the information data bits into an LDPC codeword using a predetermined coding scheme. A channel interleaver interleaves the LDPC codeword according to a predetermined channel interleaving rule. A modulator modulates the channel-interleaved LDPC codeword into a modulation symbol using a predetermined modulation scheme.

Abstract: A wireless communication system based on a Cognitive Radio (CR) is provided. A method includes checking channels unused by a licensed system through a spectrum sensing; selecting one of the channels unused by the licensed system as a control channel based on a channel quality per channel; and transmitting control information to terminals within a cell over the control channel.

Abstract: An apparatus and method for transmitting Coexistence Beacon Protocol (CBP) in a cognitive radio system are provided. The apparatus includes a detector, a controller, and a transmitter. The detector scans channels on which neighboring Base Stations (BSs) operate through a plurality of directional antennas. The controller links the plurality of directional antennas with BSs, respectively. The transmitter receives a CBP packet through the directional antenna linked with the BS, and transmits the received CBP packet to at least one or more other BSs linked with at least one or more other directional antennas.

Abstract: A wireless communication system using multiple channels is provided. An apparatus includes an allocator for, when bursts are allocated to an Accessing Terminal (AT) which utilizes a plurality of channels at the same time, allocating the same amount of the bursts to each channel in use; a generator for, when a map message to be transmitted in a primary channel of the AT is generated, generating the map message which comprises allocation information of the bursts allocated to the AT; and a transmitter for transmitting the map message in the primary channel of the AT.

Abstract: A method and apparatus for channel management in a Cognitive Radio (CR) system supporting multiple channels are provided. The method includes generating a candidate channel set from an available channel list, configuring a backup channel set by combining at least one candidate channel, and updating the backup channel set when a channel change event occurs. Accordingly, the multiple channels can be effectively used in CR communication.

Abstract: A method and apparatus for estimating a geo-location of a terminal in a wireless communication system are provided. In a method of operating a terminal for providing geo-location information in a cognitive ratio (CR) system, the method includes obtaining first ranging information and transmitting a first ranging code to a base station (BS) in a network entry process; receiving an allocated second ranging resource from the BS; and transmitting a second ranging code.

Abstract: Provided is an apparatus and method for controlling power in a cognitive radio wireless communication system, the method comprising: performing channel scheduling and the first power control for at least one terminal; checking whether the at least one terminal exist within constraint area, and determining whether the at least one terminal within constraint area cause interference to incumbent system; and performing the secondary power control so that an allocating power may be less than the maximum tolerable interference.

Abstract: A call connection method and apparatus in a communication system are provided, in which a call connection request message is received from each of first and second terminals, it is determined whether the first and second terminals are requesting a call connection to each other, one of the first and second terminals is selected if the first and second terminals are requesting a call connection to each other, the call connection request of the selected terminal is rejected, and a call is connected between the first and second terminals by performing a call connection to the selected terminal according to the call connection request of the non-selected terminal.