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 |
20090010149 | VIRTUAL MULTI-ANTENNA METHOD FOR OFDM SYSTEM AND OFDM-BASED CELLULAR SYSTEM - Provided are a virtual multi-antenna method for an orthogonal frequency division multiplexing (OFDM) system and an OFDM-based cellular system. The virtual multi-antenna method includes grouping sub-carriers in a frequency domain of an OFDM symbol and generating at least one group including G sub-carriers; and regarding the G sub-carriers included in the at least one group as multiple channels used in a multi-antenna technique and virtually applying the multi-antenna technique to the transmission and reception of the OFDM symbol. The virtual multi-antenna method can effectively reduce an interference signal and obtain the effects of a spatial division multiple access (SDMA) technique without physically using multiple antennas. | 01-08-2009 |
20090116565 | Method for selecting beams during initial synchronization process using switched beam, switched beam operation method and initial sychronization using the same - A method for selecting beams, a switched beam operation method during an initial synchronization process, and an initial synchronization method using it are provided for selecting beams to minimize the probability of occurrence of interferences between cells by considering a distance between beams within neighboring sectors during an initial synchronization process using switched beams, in an orthogonal frequency division multiplexing (OFDM) cellular system employing a smart antenna. The inventive method comprises the steps of dividing each cell into sectors, and counting the number of fixed beams per cell, and selecting a switched beam for minimizing probability of interference, from fixed beams presenting in a corresponding sector, based on distances between a selected beam and beams of all of adjacent cells and the number of cases to be selected in a subsequent time slot, according to the counted number of the fixed beams existing in each sector. | 05-07-2009 |
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 |
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 |
20100054233 | METHOD FOR SYNCHRONIZATION IN WIRELESS COMMUNICATION SYSTEM - A synchronization method is provided. In the synchronization method, a first mutual ranging symbol is transmitted to at least one other subscriber station. A second mutual ranging symbol is received from the other subscriber station. Uplink synchronization information is controlled on the basis of the second mutual ranging symbol. | 03-04-2010 |
20110280176 | A DEVICE AND METHOD FOR TRANSMITTING RELAY SYNCHRONIZATION SIGNAL ON LTE-A SYSTEM BASED ON ORTHOGONAL FREQUENCY DIVISION HAVING A MULTI-HOP RELAY - Provided is a relay-synchronization signal (R-SS) transmitting apparatus and method in an orthogonal frequency division multiplexing (OFDM)-based Long Term Evolution Advanced (LTE-A) system having a multi-hop relay. The R-SS transmitting apparatus generates a R-SS having the same peak-to-average power ratio (PAPR) characteristic as a synchronization signal (SS) and having a lower correlation characteristic than the SS, using the SS for synchronization with a terminal, for synchronization between a relay and a base station, for a synchronization between a relay and a subordinate relay, and for monitoring, by a relay, an adjacent base station or an adjacent relay | 11-17-2011 |
20120038526 | LOW-PROFILE ANTENNA RECEIVING VERTICAL POLARIZED SIGNAL - A low-profile antenna is provided. A laminated substrate is formed into a structure in which a plurality of substrates having different permittivities are stacked, and a radiator consists of a plurality of unit patches disposed on an upper surface of the laminated substrate and generates an electric field perpendicular to the upper surface of the laminated substrate. Ground vias are formed from the respective unit patches to a ground plane disposed on a lower surface of the laminated substrate through the substrates constituting the laminated substrate. In the low-profile antenna, the radiator consisting of the plurality of patches is disposed on the upper surface of the laminated substrate having a structure in which the plurality of substrates are stacked to generate a magnetic loop around the patches, so that vertical polarized signals can be received due to a magnetic field perpendicular to the upper surface of the laminated substrate. | 02-16-2012 |
20120263080 | APPARATUS AND METHOD FOR DETECTING SIGNAL IN SPATIAL MULTIPLEXING SYSTEM - Disclosed are an apparatus and a method for detecting signals in a spatial multiplexing system. An embodiment of the invention provides a signal detection apparatus for a single receiver unit equipped with a plurality of antennas in a system having at least one transmitter unit configured to transmit data streams by spatial multiplexing, where the signal detection apparatus includes: a partial linear coefficient generator unit configured to generate a linear weighting matrix by using a preset algorithm on a channel matrix formed between the transmitter unit and the single receiver unit; a partial symbol remover unit configured to generate a first symbol vector by removing all transmittable symbols for each transmitting antenna from all received data streams; and a partial symbol detector unit configured to generate a transmission symbol candidate vector by using the linear weighting matrix and the first symbol vector. | 10-18-2012 |