Patents by Inventor Keum-Chan Whang
Keum-Chan Whang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9578642Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: GrantFiled: January 13, 2015Date of Patent: February 21, 2017Assignees: ELECTRONICS & TELECOMMUNICATIONS RESEARCH INSTITUTE, INDUSTRY-ACADEMIC COOPERATION FOUNDATION, YONSEI UNIVERSITYInventors: Young-Jo Ko, Jae-Young Ahn, Kwang-Soon Kim, Jung-Hyoung Kwon, Keum-Chan Whang
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Publication number: 20150163807Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: ApplicationFiled: January 13, 2015Publication date: June 11, 2015Applicants: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE, INDUSTRY-ACADEMIC COOPERATION FOUNDATION, YONSEI UNIVERSITYInventors: Young-Jo KO, Jae-Young AHN, Kwang-Soon KIM, Jung-Hyoung KWON, Keum-Chan WHANG
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Patent number: 8983487Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: GrantFiled: December 23, 2013Date of Patent: March 17, 2015Assignees: Electronics and Telecommunications Research Institute, Industry-Academic Cooperation Foundation, Yonsei UniversityInventors: Young-Jo Ko, Jae-Young Ahn, Kwang-Soon Kim, Jung-Hyoung Kwon, Keum-Chan Whang
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Publication number: 20140112296Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: ApplicationFiled: December 23, 2013Publication date: April 24, 2014Applicants: INDUSTRY-ACADEMIC COOPERATIN FOUNDATION, YONSEI UNIVERSITY, ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTEInventors: Young-Jo KO, Jae-Young AHN, Kwang-Soon KIM, Jung-Hyoung KWON, Keum-Chan WHANG
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Patent number: 8666426Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: GrantFiled: December 19, 2005Date of Patent: March 4, 2014Assignees: Electronics and Telecommunications Research Institute, Industry-Academic Cooperation Foundation, Yonsei UniveristyInventors: Young-Jo Ko, Jae-Young Ahn, Kwang-Soon Kim, Jung-Hyoung Kwon, Keum-Chan Whang
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Patent number: 8117516Abstract: A method and an apparatus for transmitting a signal in a communication system are provided. An information vector is encoded according to a Low Density Parity Check (LDPC) encoding scheme, thereby generating an LDPC codeword. Minimum surviving check nodes are reserved for recovery of punctured nodes in the LDPC codeword. A check node is selected having a smallest cost function from among unreserved check nodes. A variable node is selected being unpunctured and having a smallest cost function from among variable nodes connected to the selected check node. The selected variable node is punctured when the selected variable node is not connected to the reserved check node. A stopping set check is performed when the selected variable node is connected to the reserved check node. The variable node is punctured when the stopping set check has been successfully performed. The check node is selected until there remains no variable node to be punctured and puncturing the variable node.Type: GrantFiled: November 5, 2007Date of Patent: February 14, 2012Assignees: Samsung Electronics Co., Ltd, Industry-Academic Cooperation Foundation, Yonsei UniversityInventors: Dong-Ho Kim, Yung-Soo Kim, Tak-Ki Yu, Keum-Chan Whang, Kwang-Soon Kim, Hyo-Yol Park
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Patent number: 8040960Abstract: A method for transmitting a signal in a wireless communication system. The method comprises the steps of: grouping two subcarriers having different channel characteristics; identifying a number of all cases occurring when either equal symbols or different symbols, among symbols determined upon applying a first modulation scheme, are mapped to the two subcarriers; and mapping two subcarriers corresponding to each of the number of all cases to one symbol according to a second modulation scheme, and transmitting the signal, wherein a modulation order of the second modulation scheme is two times higher than a modulation order of the second modulation.Type: GrantFiled: October 31, 2007Date of Patent: October 18, 2011Assignees: Samsung Electronics Co., Ltd., Industry-Academic Cooperation FoundationInventors: Sang-Min Lee, Myeon-Gyun Cho, Yu-Seok Kim, Keum-Chan Whang, Jae-Won Kang, Sun-Young Lee
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Patent number: 7734988Abstract: A method for puncturing a Low Density Parity Check (LDPC).Type: GrantFiled: October 2, 2006Date of Patent: June 8, 2010Assignees: Samsung Electronics Co., Ltd, Yonsei UniversityInventors: Dong-Ho Kim, Yung-Soo Kim, Ye-Hoon Lee, Myeon-Gyun Cho, Hyo-Yol Park, Keum-Chan Whang, Kwang-Soon Kim, Jae-Won Kang
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Patent number: 7643566Abstract: An apparatus and method for estimating a frequency offset in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided. Two time domain signals are generated from one received OFDM symbol through two observation windows with different delay times. The two time domain signals are compensated for a candidate frequency offset. A discrete Fourier transform process and a phase compensation process in a frequency domain are performed. A difference between two frequency domain signals compensated for a phase difference is computed with respect to each candidate frequency offset. For all candidate frequency offsets, difference values are compared with each other. A candidate frequency offset mapped to a minimum difference value is detected as an optimal frequency offset. The frequency offset can be more exactly estimated without consuming a bandwidth and increasing hardware complexity of a receiver.Type: GrantFiled: April 11, 2006Date of Patent: January 5, 2010Assignee: Samsung Electronics Co., Ltd.Inventors: Jong-Yoon Hwang, Kwang-Soon Kim, Keum-Chan Whang
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Publication number: 20080305818Abstract: The present invention relates to an adaptive transmitting device using limited feedback information in a mobile communication system, and a method thereof. According to an exemplary embodiment of the present invention, when the base station transmits a pilot signal to the terminal, the terminal generates channel information by using the pilot signal, generates additional channel information from the channel information, and transmits the channel information and the additional channel information to the base station. The base station determines band allocation, power allocation, and modulation methods for each use by using received feedback information, and transmits modulated traffic data to the terminal according to the determined methods.Type: ApplicationFiled: December 19, 2005Publication date: December 11, 2008Applicant: Electronics and Telecommunications Research InstituteInventors: Young-Jo Ko, Jae-Young Ahn, Kwang-Soon Kim, Jung-Hyoung Kwon, Keum-Chan Whang
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Publication number: 20080109708Abstract: A method and an apparatus for transmitting a signal in a communication system are provided. An information vector is encoded according to a Low Density Parity Check (LDPC) encoding scheme, thereby generating an LDPC codeword. Minimum surviving check nodes are reserved for recovery of punctured nodes in the LDPC codeword. A check node is selected having a smallest cost function from among unreserved check nodes. A variable node is selected being unpunctured and having a smallest cost function from among variable nodes connected to the selected check node. The selected variable node is punctured when the selected variable node is not connected to the reserved check node. A stopping set check is performed when the selected variable node is connected to the reserved check node. The variable node is punctured when the stopping set check has been successfully performed. The check node is selected until there remains no variable node to be punctured and puncturing the variable node.Type: ApplicationFiled: November 5, 2007Publication date: May 8, 2008Applicants: SAMSUNG ELECTRONICS CO., LTD., INDUSTRY-ACADEMIC COOPERATION FOUNDATION, YONSEI UNIVERSITYInventors: Dong-Ho KIM, Yung-Soo Kim, Tak-Ki Yu, Keum-Chan Whang, Kwang-Soon Kim, Hyo-Yol Park
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Publication number: 20080101491Abstract: A method for transmitting a signal in a wireless communication system. The method comprises the steps of: grouping two subcarriers having different channel characteristics; identifying a number of all cases occurring when either equal symbols or different symbols, among symbols determined upon applying a first modulation scheme, are mapped to the two subcarriers; and mapping two subcarriers corresponding to each of the number of all cases to one symbol according to a second modulation scheme, and transmitting the signal, wherein a modulation order of the second modulation scheme is two times higher than a modulation order of the second modulation.Type: ApplicationFiled: October 31, 2007Publication date: May 1, 2008Applicants: Samsung Electronics Co., Ltd., Industry-Academic Cooperation Foundation Yonsel UniversityInventors: Sang-Min Lee, Myeon-Gyun Cho, Yu-Seok Kim, Keum-Chan Whang, Jae-Won Kang, Sun-Young Lee
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Patent number: 7292644Abstract: Disclosed is a method for generating a space-time trellis code (STTC) for maximizing space-time diversity gain and coding gain in a mobile communication system including at least two transmission antennas and generating a second number of STTC codes with an information data bit stream upon receiving the information data bit stream comprised of a first number of bits.Type: GrantFiled: July 30, 2003Date of Patent: November 6, 2007Assignee: Samsung Electronics Co., Ltd.Inventors: Keum-Chan Whang, Chan-Soo Hwang
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Publication number: 20070202889Abstract: Provided is a method for puncturing a Low Density Parity Check (LDPC) code that is expressed in a factor graph configured by a bit node and a check node connected to an edge and is decoded by a parity check matrix with an information region and a parity region. A mother code with a code rate is generated. Bit nodes configuring the parity region are grouped in a block unit. A transmission code rate and the number of bits to be punctured in the mother code according to the transmission code rate are set. A puncturing process in either the block unit or a bit unit or both is performed according to the transmission code rate. All codes with required code rates can be obtained. The LDPC code puncturing method can be flexibly applied to Hybrid Automatic Repeat Request (H-ARQ) and Incremental Redundancy (IR) systems.Type: ApplicationFiled: February 7, 2007Publication date: August 30, 2007Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventors: Dong-Ho Kim, Cheol-Woo You, Yung-Soo Kim, Ye-Hoon Lee, Keum-Chan Whang, Kwang-Soon Kim, Hyo-Yol Park
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Publication number: 20070101243Abstract: A method for puncturing a Low Density Parity Check (LDPC).Type: ApplicationFiled: October 2, 2006Publication date: May 3, 2007Applicants: SAMSUNG ELECTRONICS CO., LTD, Yonsei UniversityInventors: Dong-Ho Kim, Yung-Soo Kim, Ye-Hoon Lee, Myeon-Gyun Cho, Hyo-Yol Park, Keum-Chan Whang, Kwang-Soon Kim, Jae-Won Kang
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Publication number: 20060239368Abstract: An apparatus and method for estimating a frequency offset in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided. Two time domain signals are generated from one received OFDM symbol through two observation windows with different delay times. The two time domain signals are compensated for a candidate frequency offset. A discrete Fourier transform process and a phase compensation process in a frequency domain are performed. A difference between two frequency domain signals compensated for a phase difference is computed with respect to each candidate frequency offset. For all candidate frequency offsets, difference values are compared with each other. A candidate frequency offset mapped to a minimum difference value is detected as an optimal frequency offset. The frequency offset can be more exactly estimated without consuming a bandwidth and increasing hardware complexity of a receiver.Type: ApplicationFiled: April 11, 2006Publication date: October 26, 2006Inventors: Jong-Yoon Hwang, Kwang-Soon Kim, Keum-Chan Whang
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Publication number: 20040223555Abstract: Disclosed is a method for generating a space-time trellis code (STTC) for maximizing space-time diversity gain and coding gain in a mobile communication system including at least two transmission antennas and generating a second number of STTC codes with an information data bit stream upon receiving the information data bit stream comprised of a first number of bits.Type: ApplicationFiled: July 30, 2003Publication date: November 11, 2004Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventors: Keum-Chan Whang, Chan-Soo Hwang
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Patent number: 6788733Abstract: A novel and improved method and apparatus in a communication system (100) provides for efficient processing of received signals. The method and apparatus includes converting an encoded and spectrum spread received signal to received samples, determining a first channel estimate based on a first set of pilot signal samples. The first set of pilot signal samples are included in the received samples. The received samples are passed through a correlation and decoding process in accordance with the first channel estimate to produce decoded received samples. The decoded received samples are re-encoded and re-spreaded to produce re-encoded and re-spread samples. The re-encoded and re-spread samples are modified based on the first channel estimate to produce channel modified re-encoded and re-spread samples. The received samples pass through an interference cancellation that uses the channel modified re-encoded and re-spread samples to produce a new set of received samples.Type: GrantFiled: November 9, 2000Date of Patent: September 7, 2004Assignee: Qualcomm, IncorporatedInventors: Keum-Chan Whang, Hyuck-Chan Kwon
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Patent number: 6609008Abstract: A novel and improved method and apparatus for controlling signal power level in a communication system (100) is provided by determining first and second signal to interference ratios of a received signal, respectively before and after an interference cancellation, determining a difference between the first and second signal to interference ratios, and determining, based on the difference, a signal to interference threshold for controlling power level of a signal transmitted from a source of the received signal.Type: GrantFiled: November 9, 2000Date of Patent: August 19, 2003Assignee: Qualcomm IncoporatedInventors: Keum-Chan Whang, Hyuck-Chan Kwon