Patent application number | Description | Published |
20080214115 | Apparatus and method for estimating channel in multi antenna wireless communication system - The present invention relates to an apparatus and method for estimating a channel in a wireless communication system. The apparatus according to the present invention includes an estimator for initially estimating a channel response value by using a predetermined signal among reception signals, a detector for detecting transmission signals by using the channel response value and an operator for updating the channel response value by using detected transmission signals, a detection accuracy and reception signals. | 09-04-2008 |
20080232296 | Apparatus and method for operating relay link in relay broadband wireless communication system - Provided is a relay broadband wireless communication system. The relay broadband wireless communication system includes a plurality of base stations, and one or more relay stations. The base stations perform communication with a relay station placed within a coverage area and generate state information to be provided to the relay station. The one or more relay stations are disposed at a location allowing communication with the plurality of base stations and select one or more serving base stations based on state information received from each of the base stations. | 09-25-2008 |
20080247340 | METHOD AND APPARATUS FOR TRANSMITTING AND RECEIVING DATA IN A COMMUNICATION SYSTEM - A method and apparatus for transmitting and receiving data in a Base Station (BS) of a communication system are provided. A controller determines a location of a Mobile Station (MS), and determines a transmission/reception scheme for data transmission and reception to/from the MS according to the location of the MS. A transceiver transmits and receives data to/from the MS using the determined transmission/reception scheme. Preferably, the MS is located in any one of a cell's inner region and a cell's outer region, the cell's inner region has a radius which varies according to interference between adjacent cells, and the cell's outer region is a region defined by excepting the cell's inner region from the entire cell region. | 10-09-2008 |
20080247391 | Method and apparatus for transmitting and receiving data in a communication system - A method for receiving multicast service data by a terminal in a communication system. The method includes receiving a pilot from a base station, measuring channel state information using the received pilot, and transmitting the channel state information to the base station; receiving a frame from the base station, and determining whether there is an error in the received frame; when no error has occurred in the received frame, determining whether the number of frames consecutively received without error is greater than or equal to a predetermined number; and when the number of frames consecutively received without error is greater than or equal to the predetermined number, transitioning to a non-feedback state where the terminal transmits no channel state information to the base station. The frame includes multicast service data. | 10-09-2008 |
20080247478 | Orthogonal frequency division multiplexing communication system, multi-hop system, relay station, and spatially layered transmission mode - An apparatus and method for data transmission in an Orthogonal Frequency Division Multiplexing (OFDM) communication system are provided. An OFDM system includes a reference Relay Station (RS) and a cooperative relay station respectively for performing an Spatially Layered transmission Mode (SLM) process by modulating a phase and magnitude of a signal by using a predetermined modulation order suitable for the reference relay station to obtain a spatially-layered signal and for delivering the spatially-layered signal to a target Mobile Station (MS); a Base Station (BS) for selecting the reference relay station and the cooperative relay station among a plurality of relay stations; and an mobile station for detecting data through Maximum Likelihood (ML) detection in which a signal having the largest ML is detected by comparing the received spatially-layered signal with a signal which is converted through the SLM upon receiving the spatially-layered signal from the reference relay station and the cooperative relay station. | 10-09-2008 |
20080247489 | APPARATUS AND METHOD FOR SUPPORTING DISTORTIONLESS VECTOR PERTURBATION IN MULTIPLE ANTENNA SYSTEM - An apparatus and method for supporting distortionless vector perturbation in a Multi-Input Multi-Output (MIMO) system are provided. The apparatus includes a transmitter for supporting distortionless vector perturbation in a MIMO system. The transmitter includes a label inserter for generating a label and for inserting the label into a user information bit, a scrambler for scrambling the user information bit inserted with the label and for generating N independent candidate sequences, a modulator for modulating the N independent candidate sequences according to a modulation scheme and a vector perturbation unit for adding a limited offset vector so that the modulated symbols are mapped to a constellation point in a feasible region. The apparatus and method provide vector perturbation with improved performance and reduced computational complexity. | 10-09-2008 |
20080248803 | APPARATUS AND METHOD FOR ALLOCATING FREQUENCY RESOURCE IN A COMMUNICATION SYSTEM - A method and apparatus for allocating resources for a mobile station in a communication system is provided. The method includes determining if a mobile station within a cell is located in one of a first region corresponding to a cell center, a third region corresponding to a cell edge, and a second region corresponding to an area between the first and third regions, allocating frequency resources within an entire frequency band to the mobile station when the mobile station is located in the first region, wherein the entire frequency band comprises at least a first frequency band and a second frequency band, allocating frequency resources within the first frequency band to the mobile station when the mobile station is located in the third region, and allocating frequency resources within the second frequency band to the mobile station when the mobile station is located in the second region. | 10-09-2008 |
20080285673 | Apparatus and method for reducing peak to average power ratio based on tile structure in broadband wireless communication system - A broadband wireless communication system is provided. A transmitting end of the broadband wireless communication system includes: a controller for receiving a plurality of Orthogonal Frequency Division Multiple Access (OFDMA) symbols, and for generating the same number of symbol sets corresponding to the OFDMA symbols wherein each symbol set includes a plurality of OFDMA symbols having various Peak to Average Power Ratios (PAPRs) according to several phase-shifting patterns, a selector for grouping the plurality of OFDMA symbols into symbol groups according to the same phase-shifting pattern of the several phase-shifting patterns, and for finding maximum peak value in each symbol group, and a transmitter for transmitting the symbol group having a minimum value selected from among the maximum peak values of the symbol groups. | 11-20-2008 |
20080298491 | Apparatus and method for detecting signal based on QR-decomposition in multiple input multiple output wireless communication system - An apparatus and a method are provided for detecting N number of TX signals in a MIMO wireless communication system. The apparatus includes an RF processor, a channel estimator, and a signal detector. The RF processor converts signals, received through multiple antennas, into baseband signals. The channel estimator estimates channel information of the respective antennas by using the received signals. The signal detector arranges the baseband signals of the respective antennas on the basis of the channel information, calculates a threshold value of each stage, and selects symbols with a cumulative metric smaller than or equal to the threshold value as candidates at each stage, to detect a TX signal vector with N number of symbols. | 12-04-2008 |
20080310556 | Apparatus and method for detecting signal in multiple-input multiple-output (MIMO) wireless communication system - Receiving apparatus and method in a Multiple-Input Multiple-Output (MIMO) wireless communication system are provided. The receiver having N-ary receive antennas includes a decomposer for decomposing a channel matrix to a matrix Q and a matrix R through a QR decomposition; a detector for determining a candidate group of an n-th phase by estimating a plurality of transmit signal vectors by substituting a plurality of transmittable symbols into symbol combinations of a candidate group of a (n−1)-th phase as an n-th symbol and detecting (n+1)-th through N-th symbols using characteristics of the matrix R; a calculator for calculating square Euclidean distance values between the transmit signal vectors and a receive signal vector; and a determiner for determining the candidate group of the n-th phase by selecting transmit signal vectors having the smallest square Euclidean distance value among the transmit signal vectors. | 12-18-2008 |
20090028265 | Apparatus and method for detecting signal by maximum likelihood - An apparatus and method for detecting a signal in a receiver by maximum likelihood (ML) are provided, in which symbols are detected according to the number of transmit antennas of a transmitter and a modulation scheme, channels are estimated, an equivalent channel matrix corresponding to the estimated channels is determined, a permuted equivalent channel matrix is determined by multiplying the equivalent channel matrix by a predetermined permutation matrix, the permuted equivalent channel matrix is QR decomposed, a hard decision is performed on predetermined symbols among the detected symbols using a received signal resulting from the QR decomposition, and the log likelihood ratios (LLRs) of the hard-decided symbols are determined. | 01-29-2009 |
20090034437 | Apparatus and method for canceling interference in relay station in a communication system - A method and apparatus for canceling interference between a transmission signal and a received signal in a full-duplex RS in a communication system are provided, in which an RF/IF signal received from a first node through an antenna is converted to a baseband received signal, demodulated and decoded, a baseband transmission signal is generated by encoding and decoding the decoded data, a baseband interference estimate is calculated using the baseband received signal and the baseband transmission signal, a baseband interference is eliminated from the baseband received signal according to the baseband interference estimate, the baseband transmission signal is converted to an RF/IF transmission signal for a second node, an RF/IF interference estimate is calculated by converting amplitude of the RF/IF transmission signal and delaying it, and an RF/IF interference is eliminated from the RF/IF received signal according to the RF/IF interference estimate. | 02-05-2009 |
20090061899 | APPARATUS AND METHOD FOR LOCATION ESTIMATION IN A WIRELESS COMMUNICATION SYSTEM - An apparatus and method for location estimation in a wireless communication system are provided. The method includes identifying if a received at least one signal passed through at least one repeater, when the received at least one signal is identified as having passed though at least one repeater, measuring a Base Station (BS) basis delay time and calculating a repeater basis delay time using the measured BS basis delay time, and estimating a location of the MS using the repeater basis delay time. | 03-05-2009 |
20090075659 | Apparatus and method for allocating resources based on error vector magnitude (EVM) in a broadband wireless communication system - A resource allocation in a broadband wireless communication system is provided. An apparatus for a base station in a broadband wireless communication system includes a manager for managing resources by dividing the resources into a plurality of regions based on a maximum supportable error vector magnitude (EVM) in a frequency axis; and an allocator for allocating resources of a region other than a first region, the region having the smallest maximum supportable EVM, to a service to which a maximum modulation and coding scheme (MCS) level is not applied. | 03-19-2009 |
20090086840 | Apparatus and method for transmitting feedback information in communication system - Disclosed is a system and method for transmitting feedback information in a communication system. A receiver calculates a minimum distance of each two symbol vectors among all symbol vectors which can be received through a k | 04-02-2009 |
20090086848 | Apparatus and method for reducing peak-to-average power ratio in a wireless communication system - An apparatus is provided for reducing a peak-to-average power ratio (PAPR) in a wireless communication system having multiple transmit antennas. A symbol generator generates symbols to be transmitted via the multiple transmit antennas, and a PAPR calculator calculates a PAPR value for each symbol. A detector detects a maximum PAPR value among the PAPR values of the symbols. A controller outputs a control signal to reduce a PAPR value of a corresponding symbol when the detected maximum PAPR value exceeds a reference PAPR value. A PAPR reducer reduces the PAPR value of the corresponding symbol upon receipt of the control signal. | 04-02-2009 |
20090097585 | Apparatus and method for generating per stream channel quality information in multiple-input multiple-output (MIMO) wireless communication system - The generation of per stream Channel Quality Information (CQI) in a Multiple-Input Multiple-Output (MIMO) wireless communication system is provided. An apparatus includes a receiver for receiving signals from a transmitting end via a plurality of antennas; an estimator for estimating channels per antenna in relation with the transmitting end using the received signals and constituting a channel matrix; and a generator for deriving per stream effective noise when a lattice reduction scheme is adopted and generating per stream CQI using the per stream effective noise. Thus, feedback information for a Closed Loop (CL) MIMO system can be produced by generating the per stream CQI using the effective noise obtained through the lattice reduction. | 04-16-2009 |
20090116590 | APPARATUS AND METHOD FOR DETECTING SIGNAL IN MULTI-ANTENNA SYSTEM - A method and an apparatus for detecting a signal in a multi-antenna system using a spatial multiplexing are provided. The apparatus includes at least one antenna for receiving a signal, a channel estimator for estimating a channel using the received signal, a detector for calculating multiplication values commonly used to determine a Euclidean distance using the receive signal and channel information and for detecting a transmitted signal by calculating Euclidean distances of one or more candidate symbols using the receive signal and the determined multiplication values and a decoder for demodulating and decoding the detected signal. Hence, the computational complexity of the signal detection can be mitigated. | 05-07-2009 |
20090147706 | Frame structures, method and apparatus for resource allocation in wireless communications system based on full duplex replay - Frame structures, a method and an apparatus for resource allocation in a wireless communication system based on a full duplex relay are provided. The method for a centralized resource allocation in the wireless communication system based on the full duplex relay includes receiving channel information from a plurality of mobile stations (MSs) and relay stations (RSs); scheduling radio resources for a link between a base station (BS) and the MS and a link between the BS and the RS using the channel quality; constituting a first radio resource region for the link between the BS and the RS and a second radio resource region for the link between the BS and the MS; and scheduling radio resource for a link between the RS and the MS by reusing the first radio resource region. The relay link resource is reused in the full-duplex relay structure, and the system capacity can be raised by minimizing the interference in the resource utilization. | 06-11-2009 |
20090154335 | RECEIVING APPARATUS AND METHOD FOR SINGLE CARRIER FREQUENCY DIVISION ACCESS SYSTEM - A receiver and a receiving method for a Single Carrier Frequency Division Multiple Access (SC-FDMA) system are provided. The receiver includes a matrix selector for selecting a constant channel matrix according to a Multiple-Input Multiple-Output (MIMO) reception scheme, a channel equalizer for equalizing a multi-path channel to a specific path channel in a frequency domain by using the constant channel matrix, and a MIMO detector for detecting a Euclidean distance of transmittable symbols from a time-domain Transmit (Tx) signal by using the channel equalized in the frequency domain and then for selecting a symbol having a minimum distance. | 06-18-2009 |
20090156214 | Preamble design method for reducing overhead during handover in hierarchical cellular system - Provided is a handover method of a wireless communication system using a hierarchical cellular scheme. In the method, signal quality of a serving node is measured, so that whether to start scanning for a handover is determined. When the scanning for the handover starts, signal qualities of a serving cell including the serving node and one or more neighbor cells are measured through a first preamble including a first identifier for distinguishing a cell. An intra-cell handover or an inter-cell handover is selected using the signal qualities of the serving cell and the neighbor cells. Therefore, a terminal can easily distinguish between the inter-cell handover and the intra-cell handover, and an overhead during a handover can be reduced because an intra-cell handover procedure is simplified. | 06-18-2009 |
20090160710 | Method and apparatus for estimating location to support location based service of terminal in mobile communication system - A method and an apparatus for estimating a location to support a location based service of a terminal in a mobile communication system are provided. The method includes receiving first reference signals from three base stations, calculating TDOAs, and solving a first equation using the TDOAs based on the first reference signals; when a solution of determining a location of a terminal based on the first equation is real or imaginary values, receiving second reference signals from the three base stations, calculating TDOAs, and solving a second equation using the TDOAs based on the second reference signals; and when a solution of determining the location of the terminal based on the second equation is real or imaginary values, determining the location of the terminal based on a relation between the first equation and the second equation. | 06-25-2009 |
20090286494 | Iterative tree search-based precoding technique for multiuser mimo communication system - An iterative tree search-based preceding method for a multi-user Multi-Input Multi-Output (MIMO) communication system includes determining a reference value of a cumulative branch metric of a candidate symbol, eliminating candidates having values that exceed the determined reference value of the cumulative branch metric of the candidate symbol, and registering values, which do not exceed the determined reference value of the cumulative branch metric of the candidate symbol, as entries, and selecting the least value from the values registered as the entries. Thereby, the method has low complexity and similar performance compared to an existing Sphere Encoding (SE) technique. | 11-19-2009 |
20090286546 | Apparatus and method for avoiding interference between base station and relay station when using full duplex relay in a multi hop relay system - An apparatus and method for avoiding interference between a base station and a relay station when using full duplex relay in a multi-hop relay wireless communication system are provided. An operation of a mobile station includes measuring an strength of a receive signal from a base station and an strength of a receive signal from an relay station, calculating a receive signal strength ratio of base station to relay station by dividing the strength of the receive signal from the base station by the strength of the receive signal from the relay station, determining if interference occurs using the receive signal strength ratio, and transmitting a control message representing if interference occurs. | 11-19-2009 |
20090290516 | Automatic gain control apparatus and method in a wireless communication system - An apparatus and method for adaptively adjusting a target Received Signal Strength Indicator (RSSI) for Automatic Gain Control (AGC) in a full-duplex relay apparatus with an interference cancellation function. A Signal to Interference Ratio (SIR) estimation block estimates an SIR based on an interference signal estimated from a received signal and an interference-cancelled signal determined by cancelling the estimated interference signal from the received signal. A target RSSI determination block determines a target RSSI according to the estimated SIR. An AGC block adjusts a gain for the received signal based on the determined target RSSI. | 11-26-2009 |
20100165971 | SCHEDULING METHOD OF WIRELESS COMMUNICATION SYSTEM AND APPARATUS ADAPTED THERETO - A scheduling method and an apparatus adapted thereto are disclosed that can allocate sub-carriers to a terminal at the cell edge in a wireless communication. The scheduling method includes, calculating average interference and instantaneous interference of at least two terminals for a sub-carrier, determining whether an interference for the sub-carrier is partial interference, and allocating a corresponding sub-carrier serving as transmission resource to a terminal having a higher ratio of the instantaneous interference compared to the average interference than the other terminal if an interference for the sub-carrier is partial interference. | 07-01-2010 |
20100177839 | METHOD OF DIRTY PAPER CODING USING NESTED LATTICE CODES - A method of Dirty Paper Coding DPC using nested lattices is disclosed. The complexity of DPC can be reduced by scaling nested lattices and mapping interference to a lattice point of the scaled lattice. | 07-15-2010 |
20100195543 | APPARATUS AND METHOD FOR INTERFERENCE CANCELLATION IN MOBILE FULL DUPLEX RELAY - A method and an apparatus for canceling an interference in a mobile Full Duplex Relay (FDR) are provided. A signal is received from a base station, interference canceling that uses a transmitter interference signal from which an original signal interference has been cancelled is repeatedly performed on the signal received from the base station, and an interference-cancelled signal is transmitted. | 08-05-2010 |
20100227562 | METHOD AND APPARATUS FOR ELIMINATING MULTI-USER INTERFERENCE IN MULTI-ANTENNA SYSTEM - A method and an apparatus are provided for eliminating multi-user interference in a multi-antenna system. In a BS, precoding vector information of at least one interfering user terminal interfering with a user terminal and information about a ratio of the transmission (TX) power of the user terminal to the total TX power of the BS are detected. A control signal including the detected information is transmitted to the user terminal. | 09-09-2010 |
20100271932 | APPARATUS AND METHOD FOR COMPENSATING FOR PHASE ERROR IN WIRELESS COMMUNICATION SYSTEM - An apparatus and method for compensating for a phase error in a wireless communication system are provided. The apparatus includes a reception modem, a transmission modem, a Common Phase Error (CPE) compensator, a first channel estimator, a phase compensator, and a second channel estimator. The reception modem demodulates and decodes a signal received. The transmission modem encodes and modulates a signal for transmission. The CPE compensator compensates for phase errors of at least two symbols constituting a signal. The first channel estimator estimates channels for respective bursts. The phase compensator compares phases for the channels for the respective bursts with each other and compensates for a phase difference between at least two bursts. The second channel estimator estimates an interference channel. | 10-28-2010 |
20100273498 | APPARATUS AND METHOD FOR INTERFERENCE MITIGATION IN A WIRELESS COMMUNICATION SYSTEM - An apparatus and method for mitigating inter-cell interference in a macro Base Station (BS) of a wireless communication system having at least one femto cell are provided. The method includes restricting the use of at least one code among at least one available code when forming a beam by resource block, constructing a codebook set for each resource block, when feedback information is received from at least one Mobile Station (MS), allocating a resource to the MS in consideration of the feedback information, determining a weight for forming a beam to the MS in consideration of the codebook set for each resource block and the resource allocated to the MS, and forming the beam to the MS using the weight. | 10-28-2010 |
20100322139 | Apparatus and method for simultaneous transmission scheduling in a multi-hop cellular system - An apparatus and method for simultaneous transmission scheduling in a multi-hop cellular system are provided, in which a base station presets simultaneous transmission relay station set information and transmits the simultaneous transmission relay station set information to relay stations managed by the base station, and an relay station receives the simultaneous transmission relay station set information from the base station, determines, upon receipt of a data frame from the base station, a state of the relay station preset in relation to a receiving relay station for the data frame by comparing an ID of the receiving relay station included in the data frame with the simultaneous transmission relay station set information, and operates according to the preset state. | 12-23-2010 |
20110070881 | ANTI-INTERFERENCE APPARATUS AND METHOD IN WIRELESS COMMUNICATION SYSTEM - The present invention relates to an apparatus and method for reducing the interference caused by a femtocell in a wireless communication system. The method comprises the steps of: measuring the intensity of a signal received from a terminal when the transmission mode is deactivated; and controlling the transmission mode to be activated according to the signal intensity, and thus has the advantage of decreasing the influence effects caused by the femtocell and reducing the power consumption in a femto base station. | 03-24-2011 |
20120009867 | APPARATUS AND METHOD FOR LOCATION ESTIMATION IN A WIRELESS COMMUNICATION SYSTEM - An apparatus and method for location estimation in a wireless communication system are provided. The method includes identifying if a received at least one signal passed through at least one repeater, when the received at least one signal is identified as having passed though at least one repeater, measuring a Base Station (BS) basis delay time and calculating a repeater basis delay time using the measured BS basis delay time, and estimating a location of the MS using the repeater basis delay time. | 01-12-2012 |
20120076158 | METHOD AND APPARATUS FOR TRANSMITTING/RECEIVING DATA IN SINGLE CARRIER FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM - The present invention provides a method for transmitting and receiving data in a single carrier frequency division multiple access system to which a precoding matrix is applied, and to a transmitting/receiving apparatus for same. The method for transmitting data comprises the steps of: applying selected mapping algorithm (SLM) sequences of an SLM sequence subset corresponding to a precoding matrix, to respective data; selecting the SLM sequence in which each of the applied data has the smallest peak to average power ratio (PAPR) value; and transmitting the index of the selected SLM sequence and data to which the selected SLM sequence is applied. The method for receiving data, to which a precoding matrix is applied, comprises the steps of: receiving the index of the SLM sequence selected from the SLM sequence subset corresponding to the precoding matrix, and data to which the selected SLM sequence is applied; and removing the SLM sequence from the data to which the SLM sequence is applied using the SLM sequence indicated by the index, in order to recover data. | 03-29-2012 |