Patent application number | Description | Published |
20080212530 | APPARATUS AND METHOD FOR FREQUENCY REUSE IN A MULTI INPUT MULTI OUTPUT SYSTEM - A frequency reuse apparatus and method for a Mobile Station (MS) using a multiple-antenna in a broadband wireless access communication system are provided. The method includes dividing a first frequency band into ‘N’ second frequency bands where ‘N’ equals a number of Base Stations (BSs); dividing each second frequency band into ‘n’ third frequency bands; allocating each of the ‘N’ second frequency bands according to the number of receive antennas; and allocating the third frequency bands to all of the BSs, respectively. | 09-04-2008 |
20080234003 | APPARATUS AND METHOD FOR CANCELLING FREQUENCY OFFSET INTERFERENCE IN A BROADBAND WIRELESS COMMUNICATION SYSTEM - An apparatus and method for detecting a signal in a broadband wireless communication system are provided. In a Base Station, an offset estimator estimates frequency offsets of a signal received from each of a plurality of Mobile Stations (MSs), a channel estimator estimates a channel matrix having channel coefficients of subcarriers as elements, for each MS, a modeler models the received signals using the frequency offsets of the MSs and the channel matrices of the MSs, and a detector detects signals transmitted from the MSs using the modeled received signals. | 09-25-2008 |
20080244350 | APPARATUS AND METHOD FOR AUTOMATIC REPEAT REQUEST IN MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM - A method for an Automatic Repeat reQuest (ARQ) at a receiver in a Multiple Input Multiple Output (MIMO) system wherein when a received packet is erroneous and the erroneous packet is received from the weakest antenna in a Space Multiplexing (SM) mode, a first smallest number of retransmissions is computed to acquire a Signal to Noise Ratio (SNR) within or above an Adaptive Modulation and Coding (AMC) level. When the first number of the retransmissions is greater than a threshold, the sender is requested to retransmit the packets from the strongest antenna in the SM mode and when the first number of the retransmissions is smaller than the threshold, the sender is requested to retransmit the packets from the weakest antenna in the SM mode. | 10-02-2008 |
20080248773 | APPARATUS AND METHOD FOR INTERFERENCE CANCELLATION IN multiple-antenna COMMUNICATION SYSTEM - An apparatus and method for interference cancellation in multiple-antenna communication system is disclosed. Accordingly, a receiver of a multiple-antenna communication system cancels interference by selecting either a multiple-symbol processing scheme or a single-symbol processing scheme depending on a signal type, thereby improving performance of the communication system. | 10-09-2008 |
20090011756 | Method for maintaining the continuing existence of NPD in IEEE 802.22.1 operation - Methods for maintaining continuing existence of a next-in-line protecting device in a beacon network including a primary protecting device (PPD), the next-in-line protecting device (NPD) and a plurality of secondary protecting devices (SPDs). In one method, a subset of the plurality of secondary protecting devices periodically transmit beacon messages to the primary protecting device. When the next-in-line protecting device disappears, the primary protecting device selects a secondary protecting device from among the secondary protecting devices that have transmitted the beacon messages within a certain period to be a new next-in-line protecting device. In another method, the plurality of secondary protecting devices continuously monitor an existence of the next-in-line protecting device. When the next-in-line protecting device disappears for a certain period of time, a subset of the plurality of secondary protecting devices may contend to be a new next-in-line protecting device. In still another method, the primary protecting device transmits a beacon message to the plurality of secondary protecting devices to indicate whether a next-in-line protecting device is required. When a next-in-line protecting device is required, a subset of the secondary protecting devices contend to be a new next-in-line protecting device. | 01-08-2009 |
20090011788 | Method and apparatus for jointly controlling transmit power in cognitive radio communication system - 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. | 01-08-2009 |
20090016460 | Apparatus and method for beamforming with limited feedforward channel in multiple input multiple output wireless communication system - An apparatus and method are provided for beamforming in a MIMO wireless communication system. A base station includes a first calculator that repeatedly calculates downlink beamforming vectors of the user terminals to calculate the optimal beamforming vectors for the user terminals, a quantizer that quantizes the downlink beamforming vectors in order to transmit information of the downlink beamforming vectors, a control channel transmitter that feeds forward information of the quantized downlink beamforming vectors to the user terminals, a second calculator that calculates the final downlink beamforming vectors of the user terminals, and a beamforming transmitter that sums the beamformed TX signals of the user terminals and transmits the summed TX signals through a plurality of TX antennas. | 01-15-2009 |
20090207799 | SDMA communication system for feeding back channel state information and method supporting the same - According to one aspect of the present invention, there is provided a method for feeding back Channel State Information (CSI) by a Base Station (BS) in a communication system using Space Division Multiple Access (SDMA). The CSI feedback method includes grouping Mobile Stations (MSs) into at least two groups; allocating a second feedback channel over which CSI is to be fed back, to semi-orthogonal MSs having a semi-orthogonal relationship with MSs included in a first group which is one of the at least two groups, among MSs included in a second group which is one of the at least two groups and is different from the first group; receiving CSIs being fed back from the semi-orthogonal MSs through the second feedback channel; and selecting at least one MS satisfying a semi-orthogonal criterion to the MSs included in the first group from among the semi-orthogonal MSs that feed back CSIs through the second feedback channel. | 08-20-2009 |
20090253380 | Apparatus and method for beamforming in a multiantenna multiuser communication system - A method for beamforming by a transmission device in a multiantenna multiuser communication system. The method includes grouping codebook indexes included in a codebook into codebook index combinations, and calculating a sum of transmission rate for each of the codebook index combinations; selecting a codebook index combination with a maximum sum of transmission rate as an optimal codebook index combination; and transmitting a codebook index corresponding to a particular reception device among codebook indexes included in the optimal codebook index combination, to the particular reception device. | 10-08-2009 |
20090323841 | CODEBOOK DESIGN METHOD FOR MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM AND METHOD FOR USING THE CODEBOOK - A multiple input multiple output (MIMO) communication method using a codebook is provided. The MIMO communication method may use one or more codebooks and the codebooks may change according to a transmission rank, a channel state of a user terminal, and/or a number of feedback bits. The one or more codebooks may be adaptively updated according to a time correlation coefficient of a channel. | 12-31-2009 |
20100002643 | APPARATUS AND METHOD FOR INTER-CELL INTERFERENCE CANCELLATION IN MIMO WIRELESS COMMUNICATION SYSTEM - A method for operating a Mobile Station (MS) in a Multiple Input Multiple Output (MIMO) wireless communication system is provided. The method includes measuring channel quality for a serving Base Station (BS), if the channel quality is less than a threshold, measuring interference power from one or more neighbor BSs, determining a Precoding Matrix Index (PMI) and a priority metric for each neighbor BS, and feeding back at least one of the PMI, a PMI type indicator, the priority metric, and the channel quality to the serving BS. | 01-07-2010 |
20100104032 | CODEBOOK DESIGN METHOD FOR MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM AND METHOD FOR USING THE CODEBOOK - A multiple input multiple output (MIMO) communication method using a codebook is provided. The MIMO communication method may use one or more codebooks and the codebooks may change according to a transmission rank, a channel state of a user terminal, and/or a number of feedback bits. | 04-29-2010 |
20100195505 | METHOD FOR INITIALIZING PROTECTION DEVICE AND PROTECTION DEVICE IN WIRELESS MICROPHONE BEACON SYSTEM - A method for initializing a protection device PD comprising steps of: receiving by a beacon receiver beacon information from other protection devices around the PD; sending by the beacon receiver the received beacon information to a channel monitoring decision maker within a time period set in a channel monitoring timer; determining by the channel monitoring decision maker whether there exists any primary beacon transmission device PPD; if yes, deciding the PD as a secondary beacon transmission device SPD; if no, deciding the PD as a PPD; receiving by an initialization process decision maker a determination result from the channel monitoring decision maker and determining an operation status of the PD within a time period set in the initialization process timer; outputting by the initialization process decision maker the determination result to a transmitter of the PD to decide whether the transmitter has transmitted any data or request information. | 08-05-2010 |
20100272206 | TRANSMITTING/RECEIVING APPARATUS AND METHOD THEREOF IN CODEBOOK BASED MULTIPLE ANTENNA SYSTEM - A transmission/reception apparatus and a method thereof in a codebook-based multiple antenna system is provided. In a transmission method in a codebook-based Multiple Input Multiple Output (MIMO) system, control information is received from a receiver. A codeword is determined within an Open-Loop (OL)-MIMO codebook where a Closed-Loop (CL)-MIMO codebook is reused based on the control information. At least one data stream is transmitted via at least one antenna using the determined codeword. | 10-28-2010 |
20110053633 | Method and apparatus for triggering multicell MIMO schemes in multiple antenna system - A method for triggering multicell MIMO schemes in a multiple antenna system includes transmitting, at a Mobile Station (MS), a first feedback information for single-cell closed-loop MIMO to a Base Station (BS); requesting, at the BS, Normalized Interference Power (NIP) feedback from the MS based on the first feedback information; feeding, at the MS, the NIP back to the BS; selecting, at the BS, a first NIP threshold and a second NIP threshold based on the NIP fed back from the MS; and requesting, at the MS, one of a first MIMO scheme and a second MIMO scheme by comparing the calculated first and second NIPs with the first NIP threshold and the second NIP threshold. | 03-03-2011 |
20110080971 | MULTIPLE-INPUT MULTIPLE-OUTPUT COMMUNICATION SYSTEM USING EXPLICIT FEEDBACK - A multiple input multiple output (MIMO) communication system using an explicit feedback is provided. In the MIMO communication system using the explicit feedback, a receiver may generate an explicit feedback vector by calculating an explicit channel matrix, and by vectorizing the explicit channel matrix or an explicit channel matrix processed using a predefined function. Feedback information generated based on the explicit feedback vector may be provided to a transmitter. The transmitter may reconfigure the explicit channel matrix or the processed explicit channel matrix based on the feedback information. The transmitter and the receiver may share the explicit channel matrix or the processed explicit channel matrix using an adaptively transformed codebook. | 04-07-2011 |
20110092232 | APPARATUS AND METHOD FOR ELIMINATING INTER CELL INTERFERENCE IN MULTIPLE INPUT MULTIPLE OUTPUT WIRELESS COMMUNICATION SYSTEM - Provided is a device and a method for eliminating inter-cell interference in Multiple Input Multiple Output (MIMO) wireless communication system. The method for operating a user equipment for eliminating the inter-cell interference includes determining one or more optimum bands among bands not requested to be restricted from a neighboring cell, determining at least one of band and Precoding Matrix Index (PMI) to be requested to be restricted to the neighboring cell among the determined one or more optimum bands, and feeding back at least one of the band and PMI to be requested to be restricted to the neighboring cell to a serving base station. | 04-21-2011 |
20110158192 | APPARATUS AND METHOD FOR EFFICIENTLY OPERATING FAST FEEDBACK CHANNEL IN WIRELESS COMMUNICATION SYSTEM - An apparatus and method for efficiently operating a fast feedback channel in a wireless communication system are provided. A method for operating a feedback channel in a Base Station (BS) of a wireless communication system includes identifying feedback information types of one or more feedback channels intended to be deallocated among a plurality of existing allocated feedback channels for a Mobile Station (MS), activating a bit corresponding to the identified feedback information type in a ‘deallocation bitmap’ field within a DownLink (DL) control signal, and transmitting the DL control signal to the MS. Among the feedback information types of the plurality of existing allocated feedback channels, the feedback information type having the smallest value corresponds to the highest priority bit among bits within the ‘deallocation bitmap’ field. | 06-30-2011 |
20110223949 | APPARATUS AND METHOD FOR MITIGATING INTER-CELL INTERFERENCE IN MULTIPLE ANTENNA SYSTEM - An apparatus and method for mitigating inter-cell interference in a Multiple Input Multiple Output (MIMO) system are provided. The method includes allocating a serving band for providing service to at least one Mobile Station (MS) through scheduling, receiving at least one request set for at least one neighboring cell, from at least one MS, updating the at least one request set considering a serving band of each MS, and transmitting the updated at least one request set to the at least one neighboring cell. The request set includes at least one piece of information among a band and Precoding Matrix Index (PMI) for making a use restriction request to a neighboring cell that exerts interference on an MS. | 09-15-2011 |
20130266084 | CODEBOOK DESIGN METHOD FOR MULTIPLE INPUT MULTIPLE OUTPUT SYSTEM AND METHOD FOR USING THE CODEBOOK - A multiple input multiple output (MIMO) communication method using a codebook is provided. The MIMO communication method may use one or more codebooks and the codebooks may change according to a transmission rank, a channel state of a user terminal, and/or a number of feedback bits. The one or more codebooks may be adaptively updated according to a time correlation coefficient of a channel. | 10-10-2013 |
20140120937 | APPARATUS AND METHOD FOR MITIGATING INTER-CELL INTERFERENCE IN MULTIPLE ANTENNA SYSTEM - A method for operating a Base Station (BS) in a wireless communication system is provided. The method comprises of receiving at least one request set for at least one neighboring cell, from at least one Mobile Station (MS), updating the at least one request set based at least in part on a serving band of each MS, and transmitting the updated at least one request set to the at least one neighboring cell, wherein the request set comprises a band and a Precoding Matrix Index (PMI) for making a use restriction or recommendation request to a neighboring cell. | 05-01-2014 |