Abstract: An interference determination apparatus, including a signal receiver to receive a first signal of a primary network and a second signal of a secondary network; a correlator to compute a correlation value of a first cyclic prefix included in the first signal and a correlation value of a second cyclic prefix included in the second signal; and an interference determination unit to determine an interference level or whether the interference occurs between the primary network and the secondary network, using the correlation value of the first cyclic prefix and the correlation value of the second cyclic prefix.

Abstract: Provided is a communication method of a vehicular access point, a vehicular user equipment, and a macro base station for a user present in a vehicle capable of effectively forming an operational relationship between the vehicular access point and the macro base station using a plurality of operational modes. The plurality of operational modes may be differentiated based on an operation of the vehicular access point and the macro base station, and are capable of transitioning the vehicular access point from an active state to an idle state by a triggering with respect to the vehicular access point.

Abstract: A method for selecting an antenna in an orthogonalized spatial multiplexing system. Upon receipt of at least one symbol from a transmitter via multiple receive antennas, a receiver decodes each of the received symbols; determines a rotation angle between the received symbols, and selects an optimal subset of transmit antennas using a distance between vectors of the decoded symbols; generates feedback information including the determined rotation angle and the selected optimal subset, and transmits the generated feedback information to the transmitter. Upon receipt of the feedback information, the transmitter beam-forms an antenna corresponding to the optimal subset depending on the received feedback information, and transmits a data symbol to the receiver. The receiver detects each of data symbols received from the transmitter.

Abstract: A communication method of a macro base station, a macro terminal, a micro base station, and a micro terminal determines an interference control scheme for each interference condition between a micro cell and a micro cell and between a macro cell and a micro cell in a hierarchical cellular network, and controls interference in the hierarchical cellular network where a detailed operation for each determined interference control scheme, a message associated with the detailed operation, and a resource management scheme are defined.

Abstract: A cognitive radio communication terminal including a transmission processing unit to divide data by a quiet time slot that is allocated at a first point in time of a collision detection period, to transmit at least one portion of the divided data to a reception side, and a sensing unit to determine whether at least one of a feature information and an energy of another terminal is detected in a channel with the reception side during the quiet time slot of the first point in time. Where neither the feature information nor the energy of the other terminal is detected based on a determination of the sensing unit, the transmission processing unit transmits the remaining divided data.

Abstract: Provided is a method and apparatus for determining a downlink beamforming vector in a hierarchical cell communication system. Small base stations may determine transmit beamforming vectors of the small base stations so that interference from the small base stations may be reduced in a macro terminal. A macro terminal and small terminals may determine receive beamforming vectors based on the transmit beamforming vectors of the small base stations. A macro base station may determine a transmit beamforming vector based on effective channels to terminals using the receive beamforming vectors of the terminals.

Abstract: Provided is an interference aligning method and apparatus that does not perform full feed-forwarding in a hierarchical cell communication. A macro base station may generate respective transmission beamforming vectors of macro terminals to null interference channels to pico terminals and to remove interference among the macro terminals. The effective interference channels are based on reception beamforming vectors of the pico terminals. The macro base station may transmit, to a macro terminal, a feed-forward indicator (FFI) indicating a method of transmitting information associated with a reception beamforming vector of the macro terminal. The macro terminal may obtain information associated with the reception beamforming vector based on the FFI.

Abstract: A method and apparatus of controlling resources of a femto base station for protecting a macro terminal and controlling interference among femto base stations are provided. The femto base station or a gateway of the femto base station may allocate resource blocks of a femto cell based on a silencing resource block for protecting the macro terminal. Also, the femto base station or the gateway of the femto base station may allocate the resource block of the femto cell based on a relative location between the macro base station and the femto base station and a victim macro terminal. The femto base station or the gateway of the femto base station may allocate the resource block of the femto cell based on a resource block used by a neighboring femto base station.

Abstract: A cognitive radio communication apparatus and method to control a sensing operation. The cognitive radio communication apparatus includes an information receiver to receive channel state information associated with a channel occupancy state of a primary system from at least one sensing node of a secondary system; a sensing control unit to control a sensing period of the at least one sensing node according to a change pattern of the channel occupancy state, based on the channel state information; and a control information transmitter to transmit control information associated with the controlled sensing period to at least one member node of the secondary system.

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: Provided is a method of generating a transmit beamforming vector and a receive beamforming vector to substantially eliminate the effect of interference transmitted from macro terminals to a pico base station in a hierarchical cell environment. Also, provided is a method of selecting, from a plurality of macro terminals, a macro terminal for transmitting data to a macro base station.

Abstract: A cognitive radio base station may transmit, for each channel, common control channel information to a plurality of cognitive radio terminals at different points in time, respectively. Accordingly, the cognitive radio base station may receive a channel allocation request from the plurality of cognitive radio terminals receiving the common control channel information and allocate a plurality of channels to the plurality of cognitive radio terminals, respectively, to perform communication. In response to another terminal existing in a corresponding channel, the cognitive radio base station may update the common control channel information and switch to another channel to transmit subsequent common control channel information at, for example, a closest point in time to thereby broadcast the updated common control channel information to the plurality of cognitive radio terminals using the switched channel.

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 method and apparatus for controlling transmission power in a wireless network area is provided. A target base station may control transmission power in cooperation with a neighboring base station and, thus, a satisfaction with a Quality of Service (QoS) of target terminals may be improved. Additionally, the target base station may determine whether to control the transmission power in cooperation with the neighboring base station, based on a possible improvement in satisfaction with the QoS of the target terminals.

Abstract: A cognitive radio communication apparatus and method which adaptably controls a sensing reference level based on a transmission power of a transmitter is provided. A cognitive radio communication apparatus includes a sensing reference level control unit to adaptably control a sensing reference level based on a transmission power of a secondary transmitter included in a secondary network, and a fast sensing unit to determine whether a signal received for a predetermined time period exists based on the controlled sensing reference level.

Abstract: A communication method of a macro base station including reporting information about a broadcast channel section in order to identify a femtocell in the macrocell, is provided. The macro base station receives position information of a mobile terminal and a request for information about neighboring femto base stations from the mobile terminal, when the mobile terminal identifies an accessible femto base station in the broadcast channel section. The macro base station generates a list of the neighboring femto base stations and information about the neighboring femto base stations based on the position information of the mobile terminal, and transmits the list and the information about the neighboring femto base stations to the mobile terminal.

Abstract: Provided is a cognitive inter-cell interference control method and apparatus. Inter-cell interference may be measured based on various methods in order to recognize an interference channel, and an appropriate interference control algorithm may be applied to the interference channel by modeling based on overhead. Accordingly, interference may be controlled.

Abstract: A method is provided for efficiently allocating a transmission period in a wireless network system. An access point (AP) transmits a PSMP frame indicating a downlink period provided to each station (STA) and a minimum amount of an uplink period allocated to each STA, and at least one sub PSMP frame indicating an uplink period additionally provided for an STA that transmitted a resource request message for remaining queued data in the uplink period indicated by the PSMP frame. If the uplink period indicated by the PSMP frame is insufficient to transmit the queued data, the STA transmits a data unit including a part of the queued data and a resource request message for the remaining queued data in the uplink period. After transmitting the resource request message, the STA receives the sub PSMP frame after the full period indicated by the sub PSMP frame, and transmits the remaining queued data to the AP in the uplink period indicted by the sub PSMP frame.

Abstract: Communication methods of a macro base station which collects position information about a mobile micro base station and that is served by the macro base station, predicts a channel between the macro base station and the micro base station, and performs a handover between the macro base station and the micro base station based on a state of the predicted channel is provided.

Abstract: In a system for sharing hybrid resources in an independent network, each one of a plurality of stations preferably employs a sharing authority transferring protocol that allows the network control function to be moved from station to station depending on the network traffic. Although a distributed coordination method is normally used in the network, when an individual station determines that a real-time data stream is intended for the station, an apparatus having a method and data format for the use thereof allows control to be transferred to the targeted station. This allows the targeted station to control the sharing of the wireless hybrid resources using a centralized control method in a direct mode for the duration of the real-time service transmission, thereby optimizing network efficiency. As a result of using the distributed control authority of the present invention, a station may be freely subscribe/withdraw to/from the network.