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Do-Seob Ahn, Daejeon KR

Do-Seob Ahn, Daejeon KR

Patent application numberDescriptionPublished
20090268841POWER CONTROL SYSTEM AND METHOD FOR COMMUNICATION SYSTEM USING SPACE-TIME TRANSMIT DIVERSITY SCHEME - A power control system and method for communication system using space-time transmit diversity scheme. In the power control method, transmission power information of a plurality of antennas or a plurality of subcarriers is monitored. A new space-time code is generated by concatenating the monitored transmission power information and symbols to be transmitted. Symbols encoded using the generated space-time code are generated and the encoded symbols are transmitted. Accordingly, after determining the transmission power of each antenna, the transmission power information is monitored so that the transmission power information that does not experience the channel gain can be used at a next slot. Therefore, the performance degradation due to the round trip time can be reduced, thereby improving the system capacity and performance.10-29-2009
20090274246APPARATUS AND METHOD FOR PHASE RECOVERY USING INDEPENDENTLY DECODABLE COMPONENT CODES OF CHANNEL CODE IN WIRELESS COMMUNICATION SYSTEM - An apparatus and method for phase recovery in a wireless communication system employs independently decodable component codes. The apparatus includes a decoding unit for decoding the input signal to thereby output the decoding value; an estimation unit for estimating phase errors of the received signal by estimating phase errors of the each component codeword in the received signal to thereby generate phase error estimation values; and a correction unit for correcting the phase of received signal using the phase error estimation values to thereby generate the phase corrected signal in an effective manner.11-05-2009
20100015972METHOD AND APPARATUS FOR HANDOVER IN MOBILE COMMUNICATION NETWORK INCLUDING SATELLITE NETWORK - Provided are a method and mobile communication terminal for handover in a mobile communication network including at least one mobile communication base station and a communication satellite. The handover method includes the steps of: (a) calculating a signal power received from a currently communicating mobile communication base station among the at least one mobile communication base station; (b) calculating a signal power received from each of the communication satellite and the at least one mobile communication base station except the base station of step (a); (c) selecting a mobile communication base station having the highest among the calculated signal powers except the signal power received from the communication satellite and the signal power received from the base station of step (a); and (d) when the signal power calculated in step (a) is below a predetermined minimum handover power, a difference between the signal power of the selected mobile communication base station and the signal power calculated in step (a) is equal to or below a first terrestrial handover sensitivity, and there is no other mobile communication base station capable of communicating with the mobile communication terminal, performing handover to the communication satellite.01-21-2010
20100123620NGSO COMMUNICATION APPARATUS FOR EXTENDING OPERATION TIME AND REDUCING NUMBER OF SATELLITES USING ATC, AND ATC AND OPERATING METHOD THEREOF - Disclosed are a non geostationary satellite orbit (NGSO) communication apparatus that extends an operation time using an ancillary territory component (ATC) and reduces a number of satellites, and an ATC and an operating method thereof. The NGSO communication apparatus for extending an operation time using an ATC and reducing a number of satellites may include a first ATC that communicates with a mobile earth station (MES), and a second ATC that communicate with the first ATC to relay data between the MES and the satellite when the first ATC is unable to communication with the satellite revolving along an orbit.05-20-2010
20100128656SATELLITE, MOBILE TERMINAL, AND COMPLEMENTARY TERRESTRIAL COMPONENT IN OFDM BASED MULTI-BEAM SATELLITE SYSTEM REUSING THE SAME FREQUENCY BAND FOR ALL THE BEAMS, AND COMMUNICATION METHOD THEREOF - Provided is a communication method of a mobile terminal in an orthogonal frequency division multiplexing (OFDM) based multi-beam satellite system reusing the same frequency band for all the beams, the method including: receiving location information of the mobile terminal from a satellite to determine a location of the mobile terminal within multiple beams; determining a subcarrier group for a communication with the satellite according to the location of the mobile terminal within the multiple beams; and communicating with the satellite using the subcarrier group for the communication with the satellite.05-27-2010
20100135274HIERARCHICAL RANDOM ACCES METHOD FOR WIRELESS COMMUNICATION SYSTEM HAVING SIGNIFICANTLY LARGE CELL - Disclosed is a hierarchical random access method for a wireless communication system having a significantly large cell. According to the present invention, a length of a preamble sequence and a length of a reference slot may be designed based on a terminal having greatest capacity of adjusting a timing error arrived at a base station, and a slot length may be designed to be an integer multiple of the length of the reference slot depending on a timing error correction capacity, thereby enabling terminals to use various slot lengths.06-03-2010
20100138713INTERACTION METHOD BETWEEN ARQ AND HARQ FOR SYSTEMS WITH LONG ROUNDTRIP DELAY - Disclosed is an interaction method between an automatic repeat request (ARQ) and a hybrid automatic repeat request (HARQ) in a system having a long roundtrip delay. A transmission window for the ARQ is operated using inner feedback information from the HARQ, and a waiting window is operated using ARQ status information.06-03-2010
20100157857APPARATUS AND METHOD FOR SHARING OF FREQUENCY ALLOCATED FOR MOBILE SATELLITE SERVICE USING SATELLITE AND ITS COMPLEMENTARY GROUND COMPONENT - A disclose is a frequency sharing apparatus and method for a mobile satellite service using a satellite and a CGC of the satellite. The frequency sharing method may include measuring a signal strength of a signal received from a satellite, determining a communication mode according to the measured signal strength; and communicating with one of the satellite and a CGC of the satellite, depending on the communication mode.06-24-2010
20100157880METHOD OF ESTABLISHING UPLINK IN MOBILE SATELLITE COMMUNICATION SYSTEM - Provided is a method of establishing an uplink in a mobile satellite communication system, the method including: receiving a random uplink access signal from terminals included in a coverage of a satellite beam; estimating a location of each of the terminals; calculating an uplink transmission point in time when each of the terminals transmits an uplink signal, based on the estimated location of each of the terminals; transmitting, to each of the terminals, the calculated uplink transmission point in time; and receiving the uplink signal from each of the terminals at the calculated uplink transmission point in time.06-24-2010
20100248714METHOD OF TRANSMITTING SIGNAL IN SATELLITE COMMUNICATION SYSTEM WITH TERRESTRIAL COMPONENT - The present invention relates to a method of transmitting a signal in a satellite communication system with a terrestrial component. The present invention transmits a signal using a method of transmitting a space-time code for joint communication between a satellite and a terrestrial component in a satellite system with a terrestrial component. Therefore, using the method of transmitting a space-time code, it is possible to obtain a space-time diversity gain in a satellite communication system with a terrestrial component. Further, it is possible to improve the receiving quality of a satellite signal at an area where the terrestrial component is located and increase the coverage of the terrestrial component.09-30-2010
20100251053SYSTEM AND METHOD FOR REUSING RADIO RESOURCES - The present invention relates to a system and method of reusing radio resources capable of improving radio resource efficiency. According to an embodiment of the present invention, in a communication system including a repeater that retransmits signals transmitted from a satellite to user terminals, it is possible to reuse some of the radio resources used in a wide area coverage, such as the satellite, in a repeater coverage. Therefore, it is possible to ensure radio resources such that repeater data can be transmitted to user terminals without additional radio resources.09-30-2010
20100304668COMMUNICATION METHOD IN MOBILE COMMUNICATION SYSTEM - The present invention relates to a communication method in a mobile communication system. An exemplary embodiment of the present invention provides a mobile satellite communication system having a complementary terrestrial component among various mobile communication systems. The mobile satellite communication system can simultaneously provide a communication service and a broadcasting service to a terminal according to integration between communication and broadcasting. Different signal transmission methods are used between the complementary terrestrial component and a satellite. Specifically, a time division duplex method and a frequency division duplex method are used together and resources are allocated. As a result, system throughput can be increased, and local broadcasting contents can be effectively transmitted to the terminal.12-02-2010
20110044237METHOD AND APPARATUS FOR ALLOCATING TRAFFIC RESOURCES IN MULTI-BEAM SATELLITE COMMUNICATION SYSTEM - In a system where satellite communication using multi-beams is performed for each group including a plurality of beams, a required data transmission rate of each beam is detected for each group, more traffic resources are allocated to a beam having a higher required data transmission rate than other beams based on the detection result, and data traffic transmitted to each beam in the group is adaptively controlled.02-24-2011
20110053628SERVICE PROVIDING SYSTEM AND METHOD IN SATELLITE COMMUNICATION SYSTEM - A service providing method in a satellite communication system includes: confirming positions of terminals when the terminals existing within a service area and intended to receive a service is connected to a satellite base station or a complementary terrestrial component; confirming first terminals, which communicate with the satellite base station, and second terminals, which communicate with the complementary terrestrial component, according to the positions of the terminals; allocating resources usable when communicating with the first terminals and resources usable when communicating with the second terminals; and providing a service to the terminals by using the allocated resources through multi-beams of the satellite base station and multi-beams of the complementary terrestrial component.03-03-2011
20110143695SENSING APPARATUS, NETWORK SYSTEM AND CONTROLLING METHOD ON THE BASIS OF SATELLITE - Disclosed is a sensing apparatus, a network system, and a controlling method on the basis of a satellite. A satellite-based sensing network system, comprising: a plurality of satellite transmitters that collect information on a peripheral environment and an operating state, and transmits it to peripheral satellites; a satellite wireless receiving/display device that directly receives and displays the information collected from the satellites; a ground control center that receives, stores, and analyzes the information collected from the satellites; and a management center that maintains and repairs the satellite transmitter based on the analyzed results.06-16-2011
20110149836POWER CONTROLLED ADAPTIVE MODULATION AND CODING SCHEME IN SATELLITE COMMUNICATIONS SYSTEM - A power controlled adaptive modulation and coding (AMC) scheme in a satellite communications system includes: calculating, by a user terminal, a received signal-to-noise ratio (SNR) through a packet received from a base station; removing a power control level applied to a packet received before the received packet from the calculated received SNR, and deciding the value obtained by decreasing the calculated received SNR by the power control level; deciding an AMC mode based on the decided received SNR; determining whether power control is required, and deciding a required power control magnitude depending on a channel state positioned in the AMC mode range; transmitting the decided AMC mode and the decided power control information to the base station through channel quality indicator (CQI) feedback; and applying the AMC mode based on information received, and increasing a power by a power control magnitude decided from the received information.06-23-2011
20110149837METHOD FOR MOBILE SATELLITE COMMUNICATION BY COORDINATED MULTI-POINT TRANSMISSION AND APPARATUS THEREOF - Provided is mobile satellite communication method and apparatus. The satellite communication method includes detecting a location of a terminal, determining a signal transmission scheme for the terminal using the terminal location, determining a subcarrier region to transmit a signal to the terminal using the location of the terminal, and communicating with the terminal using the determined signal transmission scheme and the determined subcarrier region.06-23-2011

Patent applications by Do-Seob Ahn, Daejeon KR