Abstract: Provided are an apparatus and method for time synchronization in a Precision Time Protocol (PTP) network. According to an aspect, there is provided a time synchronization apparatus including: a synchronization unit configured to perform time synchronization between a master and at least one slave based on the number of synchronization messages that are sent from the master; a state-of-synchronization determiner configured to measure performance of the synchronization to thereby determine the state of the synchronization; and a number-of-messages adjustor configured to adjust the number of synchronization messages based on the state of the synchronization. Therefore, by automatically adjusting the number of synchronization messages that are sent from a master according to network traffic, the states of slave nodes, etc., it is possible to minimize entire network traffic and optimize the synchronization performance of nodes.

Abstract: A scheduling method in a wireless communication includes receiving a Channel Quality Indicator (CQI) from a plurality of terminals. The method also includes determining an average transmission rate of each terminal based on the CQI by approximating an instantaneous transmission rate distribution to a Gaussian distribution. The method further includes determining a weight of each terminal such that the average transmission rate of each terminal satisfies a target transmission rate. The method also includes selecting a terminal set by applying the determined weight. Thus, it is possible to control the fairness between the terminals and to efficiently control the transmission rate of the terminals according to the required transmission rate and the channel environment of the terminals.

Abstract: A wireless communication method and apparatus using adaptive transmission polarization control are provided. The wireless communication apparatus includes an orthogonal polarization antenna, a channel state estimator, and a transmission polarization state (TPS) selector. The orthogonal polarization antenna receives at least one reference signal. The channel state estimator estimates a wireless polarization channel on the basis of the reference signal. The TPS selector selects a TPS corresponding to the estimated wireless polarization channel from among a plurality of predefined TPSs, and feeds back the selected TPS information. Accordingly, the wireless communication apparatus feeds back information for polarization control using minimum uplink wireless resources, and maximizes a transmission capacity on the basis of the feedback information.

Abstract: A transmission method and apparatus utilizing Multiple-Input and Multiple-Output (MIMO) precoding based on Distributed Antenna Systems (DASs) are provided. The transmission method includes determining active antenna ports, for a User Equipment (UE) having multiple receive antennas, from among a plurality of Distributed Antenna Ports (DAPs) evenly placed in a service area; assigning a Multiple-Input and Multiple-Output (MIMO) mode to the UE and notifying the UE of the MIMO mode assignment; determining a signal precoding vector on a basis of feedback information for the MIMO mode received from the UE; and precoding a signal using the signal precoding vector and transmitting the precoded signal through the active antenna ports.

Abstract: A channel condition information feedback method and apparatus are provided for a collaborative wireless communication network using a multiple input multiple output antenna system. The apparatus includes a downlink channel estimator that estimates channels of adjacent base stations, groups base stations from among the adjacent base stations that are capable of collaborative communication, and obtains a maximum singular vector to base stations belonged to a same group; and a vector selector which selects a weight vector most accurately representing the maximum singular vector and a complex variable most accurately representing the maximum singular vector in combination with the weight vector.

Abstract: A method and an apparatus allocate a cell identifier in a self-organizing network. A database stores and obtains position information of a plurality of femto base stations. A Physical Cell Identifier (PCID) reconfiguring unit configures an initial Merge Table (MT) including allocation information of a PCID based on the position information of the femto base station and minimizes the number of rows or columns according to at least one permutation set in the initial MT.

Abstract: An apparatus and method for automatically setting a configuration in a home base station. In the method for automatically setting a configuration in a home base station, wireless setting information of a neighbor base station and a neighbor home base station is retrieved through a communication interface for a terminal operation when updated wireless setting information is not received from a network apparatus. The retrieved wireless setting information is transmitted to the network apparatus. An operation is performed by reflecting last wireless setting information when the last wireless setting information is received from the network apparatus. The configuration can be automatically set by monitoring an environment of a neighbor base station without a direct operation of an engineer, transmitting a monitoring result to a server, and receiving FA information and PN code information from the server.

Abstract: A method and system for operating cells in a network where macro cells and home cells coexist are provided.

Abstract: A method and an apparatus for sending and receiving channel state information in network Multiple-Input Multiple-Output (MIMO) wireless communication systems are provided. Hybrid feedback technology is provided to transfer complete Channel State Information (CSI) to a transmitter by efficiently combining limited amounts of long-term channel information and short-term channel information are in a down link MIMO network system.

Abstract: A wireless communication method and apparatus using adaptive transmission polarization control are provided. The wireless communication apparatus includes an orthogonal polarization antenna, a channel state estimator, and a transmission polarization state (TPS) selector. The orthogonal polarization antenna receives at least one reference signal. The channel state estimator estimates a wireless polarization channel on the basis of the reference signal. The TPS selector selects a TPS corresponding to the estimated wireless polarization channel from among a plurality of predefined TPSs, and feeds back the selected TPS information. Accordingly, the wireless communication apparatus feeds back information for polarization control using minimum uplink wireless resources, and maximizes a transmission capacity on the basis of the feedback information.

Abstract: A transmission method and apparatus utilizing Multiple-Input and Multiple-Output (MIMO) precoding based on Distributed Antenna Systems (DASs) are provided. The transmission method includes determining active antenna ports, for a User Equipment (UE) having multiple receive antennas, from among a plurality of Distributed Antenna Ports (DAPs) evenly placed in a service area; assigning a Multiple-Input and Multiple-Output (MIMO) mode to the UE and notifying the UE of the MIMO mode assignment; determining a signal precoding vector on a basis of feedback information for the MIMO mode received from the UE; and precoding a signal using the signal precoding vector and transmitting the precoded signal through the active antenna ports.

Abstract: An apparatus and method for transmitting and receiving packet data using multiple antennas in a wireless communication system is provided. In a wireless communication, system using multiple antennas, the apparatus and method can efficiently transmit and receive packet data according to channel conditions without a waste of transmission bandwidth.

Abstract: Feedback methods and apparatuses are provided for efficiently feeding back downlink Channel State Information (CSI) using limited information in a DAS-based wireless communication system.

Abstract: An apparatus and method for beamforming of a terminal in a Multiple Input Multiple Output (MIMO) wireless communication system are provided. The method includes transmitting sounding signals beamformed through a plurality of beamforming weight vectors in sequence, receiving control information indicative of an uplink weight vector determined by a base station and a maximum channel quality value using the sounding signals and transmitting a transmit signal beamformed with the uplink weight vector via a plurality of antennas.

Abstract: A scheduling method in a wireless communication includes receiving a Channel Quality Indicator (CQI) from a plurality of terminals. The method also includes determining an average transmission rate of each terminal based on the CQI by approximating an instantaneous transmission rate distribution to a Gaussian distribution. The method further includes determining a weight of each terminal such that the average transmission rate of each terminal satisfies a target transmission rate. The method also includes selecting a terminal set by applying the determined weight. Thus, it is possible to control the fairness between the terminals and to efficiently control the transmission rate of the terminals according to the required transmission rate and the channel environment of the terminals.

Abstract: Provided is a method of managing a neighbor relation table by a base station in a wireless communication system having a self-organizing network function, which includes receiving a neighbor base station report from a terminal; comparing the neighbor base station report with a stored neighbor relation table; calculating a statistic value of a new base station when the new base station is present in the comparison step; and adding the new base station to the stored neighbor relation table when the statistic value is equal to or greater than a first reference value.

Abstract: A method and an apparatus for sending and receiving channel state information in network Multiple-Input Multiple-Output (MIMO) wireless communication systems are provided. Hybrid feedback technology is provided to transfer complete Channel State Information (CSI) to a transmitter by efficiently combining limited amounts of long-term channel information and short-term channel information are in a down link MIMO network system.

Abstract: A method and system for operating cells in a network where macro cells and home cells coexist are provided.

Abstract: An apparatus and method for transmitting/receiving data in a mobile communication system using multiple antennas are provided. A receiver estimates a fading channel of received data, selects a weight set relative to a maximum data transmission rate from at least one weight set with elements of a plurality of orthogonal weight vectors, and transmits feedback information including the selected weight set and channel-by-channel state information to a transmitter. The transmitter demultiplexes data to be transmitted on a basis of the feedback information into at least one sub-data stream, multiplies each sub-data stream by an associated weight, and transmits the data.

Abstract: A method and an apparatus allocate a cell identifier in a self-organizing network. A database stores and obtains position information of a plurality of femto base stations. A Physical Cell Identifier (PCID) reconfiguring unit configures an initial Merge Table (MT) including allocation information of a PCID based on the position information of the femto base station and minimizes the number of rows or columns according to at least one permutation set in the initial MT.