Patents by Inventor Zheng Zi Li
Zheng Zi Li 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: 8885737Abstract: Provided are a decoding apparatus and method for a system supporting an Orthogonal Frequency Division Multiple Access (OFDMA) scheme, the apparatus and method compensating received signals according to a wireless channel estimation result and thereby simply performing decoding by a coherent method. The decoding method includes the steps of: receiving a Quadrature phase shift keying (QPSK) modulated signal; compensating the received signals by applying a result of channel estimation based on pilot signals to the received signals; performing subcarrier demodulation to generate correlation metrics on the basis of the compensated received signals; and performing decoding using a decoding metric derived from the correlation metrics. The decoding apparatus and method compensate a received wireless signal according to a channel estimation result of a wireless channel through which a signal is transmitted, thereby performing decoding by a coherent method having a simple structure.Type: GrantFiled: February 7, 2007Date of Patent: November 11, 2014Assignee: Intellectual Discovery Co., Ltd.Inventors: Jae Hyeong Kim, Yong Suk Hwang, Zheng Zi Li
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Patent number: 8861633Abstract: A method for transmitting pilots in a wireless communication system includes generating first two pilots for a first antenna. Second two pilots for a second antenna are generated by multiplying the first two pilots with two weight values respectively. The first two pilots are transmitted over two Orthogonal Frequency Division Multiplexing (OFDM) symbols via the first antenna. The second two pilots are transmitted over the two OFDM symbols via the second antenna, wherein each weight value is determined based on a value used to obtain a symbol index of a corresponding OFDM symbol of the two OFDM symbols within a slot. Symbol indexes for the two OFDM symbols are consecutive, and the two weight values are different with each other.Type: GrantFiled: August 23, 2012Date of Patent: October 14, 2014Assignee: Intellectual Discovery Co., Ltd.Inventors: Byung-Chul Kim, Zheng Zi Li, Sang-Bae Ji
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Patent number: 8644363Abstract: The present invention relates to an apparatus and method for estimating a channel in a MIMO wireless telecommunication system supporting the 0FDM/0FDMA. The present invention, in estimating a channel by using two or more pilots included in at least one received signal among received signals of a first channel and a second channel received through a first receiving antenna and received signals of a third channel and a fourth channel received through a second receiving antenna, determines a subchannel mapping rule respectively for the received signals of the first channel to the fourth channel, and estimates a channel with a different method according to the determined subchannel mapping rule.Type: GrantFiled: December 31, 2007Date of Patent: February 4, 2014Assignee: Intellectual Discovery Co., Ltd.Inventors: Zheng Zi Li, Byung-Chul Kim
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Patent number: 8588315Abstract: Provided are a decoding apparatus, a decoding method and a receiving apparatus for decoding in a system supporting an OFDM/OFDMA scheme. The decoding method includes the steps of: receiving phase-modulated signal; performing subcarrier demodulation on the received signal and generating correlation metrics; generating decoding metrics using the correlation metrics; and determining a payload using the largest metric of the decoding metrics and at least one of an average metric and the second largest metric of the decoding metrics.Type: GrantFiled: February 21, 2007Date of Patent: November 19, 2013Assignee: Intellectual Discovery Co., Ltd.Inventors: Zheng Zi Li, Yong Suk Hwang, Jae Hyeong Kim, Sang Bae Ji
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Publication number: 20130034175Abstract: A method for transmitting pilots in a wireless communication system includes generating first two pilots for a first antenna. Second two pilots for a second antenna are generated by multiplying the first two pilots with two weight values respectively. The first two pilots are transmitted over two Orthogonal Frequency Division Multiplexing (OFDM) symbols via the first antenna. The second two pilots are transmitted over the two OFDM symbols via the second antenna, wherein each weight value is determined based on a value used to obtain a symbol index of a corresponding OFDM symbol of the two OFDM symbols within a slot. Symbol indexes for the two OFDM symbols are consecutive, and the two weight values are different with each other.Type: ApplicationFiled: August 23, 2012Publication date: February 7, 2013Applicant: SEAH NETWORKS CO., LTD.Inventors: Byung-Chul Kim, Zheng Zi Li, Sang-Bae Ji
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Patent number: 8165249Abstract: The present invention relates to an apparatus and method for estimating and compensating for a time offset and a carrier frequency offset in a Multiple Input Multiple Output (MIMO) communication system that supports Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiplexing Access (OFDMA). According to the present invention, a phase difference of pilot signals of the same transmitting antenna, which are received through receiving antennas, is calculated. An arc tangent operation is then carried out on the phase difference of the pilot signals to calculate a time offset linear phase and/or a carrier frequency offset linear phase. Further, a time offset compensation value and/or a carrier frequency offset compensation value are found by employing the time offset linear phase and/or the carrier frequency offset linear phase.Type: GrantFiled: August 30, 2007Date of Patent: April 24, 2012Assignee: Seah Networks Co., Ltd.Inventors: Zheng Zi Li, Byung-Chul Kim, Sang-Bae Ji
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Publication number: 20100085866Abstract: The present invention relates to an apparatus and method for estimating a channel in a MIMO wireless telecommunication system supporting the 0FDM/0FDMA. The present invention, in estimating a channel by using two or more pilots included in at least one received signal among received signals of a first channel and a second channel received through a first receiving antenna and received signals of a third channel and a fourth channel received through a second receiving antenna, determines a subchannel mapping rule respectively for the received signals of the first channel to the fourth channel, and estimates a channel with a different method according to the determined subchannel mapping rule.Type: ApplicationFiled: December 31, 2007Publication date: April 8, 2010Applicant: POSDATA CO., LTD.Inventors: Zheng Zi Li, Byung-Chul Kim
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Publication number: 20100027698Abstract: A channel estimation apparatus of the present invention includes a preamble channel operation unit for carrying out an operation on pilot channel estimation values of pilots, which are transmitted from a transmitting antenna that transmits a preamble, as an improved pilot channel estimation value by employing a preamble channel estimation value based on a preamble included in received signals respectively received by a plurality of receiving antennas, a first channel estimation unit for estimating a channel for each of the receiving antennas through interpolation of a symbol axis and a frequency axis employing the improved pilot channel estimation value, and a second channel estimation unit for estimating a channel for each of the receiving antennas through interpolation of a symbol axis and a frequency axis employing pilot channel estimation values of pilots transmitted from the same transmitting antenna, of pilots transmitted from a transmitting antenna that does not transmit the preamble, of a plurality ofType: ApplicationFiled: October 11, 2007Publication date: February 4, 2010Applicant: POSDATA CO., LTD.Inventors: Byung-Chul Kim, Zheng Zi Li, Sang-Bae Ji
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Publication number: 20100008216Abstract: The present invention relates to an apparatus and method for estimating and compensating for a time offset and a carrier frequency offset in a Multiple Input Multiple Output (MIMO) communication system that supports Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiplexing Access (OFDMA). According to the present invention, a phase difference of pilot signals of the same transmitting antenna, which are received through receiving antennas, is calculated. An arc tangent operation is then carried out on the phase difference of the pilot signals to calculate a time offset linear phase and/or a carrier frequency offset linear phase. Further, a time offset compensation value and/or a carrier frequency offset compensation value are found by employing the time offset linear phase and/or the carrier frequency offset linear phase.Type: ApplicationFiled: August 30, 2007Publication date: January 14, 2010Applicant: Posdata Co., Ltd.Inventors: Zheng Zi Li, Byung-Chul Kim, Sang-Bae Ji
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Publication number: 20090052563Abstract: Provided are a decoding apparatus and method for a system supporting an Orthogonal Frequency Division Multiple Access (OFDMA) scheme, the apparatus and method compensating received signals according to a wireless channel estimation result and thereby simply performing decoding by a coherent method. The decoding method includes the steps of: receiving a Quadrature phase shift keying (QPSK) modulated signal; compensating the received signals by applying a result of channel estimation based on pilot signals to the received signals; performing subcarrier demodulation to generate correlation metrics on the basis of the compensated received signals; and performing decoding using a decoding metric derived from the correlation metrics. The decoding apparatus and method compensate a received wireless signal according to a channel estimation result of a wireless channel through which a signal is transmitted, thereby performing decoding by a coherent method having a simple structure.Type: ApplicationFiled: February 7, 2007Publication date: February 26, 2009Inventors: Jae Hyeong Kim, Yong Suk Hwang, Zheng Zi Li
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Publication number: 20090052596Abstract: Provided are a decoding apparatus and method for a system supporting an Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme, the apparatus and method capable of simply performing decoding by a non-coherent method. The decoding method includes the steps or receiving quadrature phase shift keying (QPSK) modulated signal; performing subcarrier demodulation whereby correlation metrics are generated on the basis of the received signal; and performing decoding using a decoding metric derived from the correlation metrics. The correlation metrics are obtained by multiplying tile, bin or zone of received signal by sets of basis vectors.Type: ApplicationFiled: February 21, 2007Publication date: February 26, 2009Inventors: Zheng Zi Li, Yong Suk Hwang, Jae Hyeong Kim
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Publication number: 20090046799Abstract: Provided are an apparatus and method for efficiently decoding signals input through a plurality of antennas in a system supporting an Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme. A method for decoding signals received via at least two paths through a plurality of antennas in a system supporting an 0FDM/0FDMA scheme, the method comprising the steps of: measuring power of a signal received via each path; generating correlation metrics by calculating inner products of basis vector sets or multiplying the basis vector sets in units of tiles or bins of the signal; generating decoding metrics based on the measured power of each path and the correlation metrics; and determining a payload on the basis of the decoding metrics.Type: ApplicationFiled: February 21, 2007Publication date: February 19, 2009Inventors: Zheng Zi Li, Yong Suk Hwang, Jae Hyeong Kim
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Publication number: 20090010348Abstract: Provided are a decoding apparatus, a decoding method and a receiving apparatus for decoding in a system supporting an OFDM/OFDMA scheme. The decoding method includes the steps of: receiving phase-modulated signal; performing subcarrier demodulation on the received signal and generating correlation metrics; generating decoding metrics using the correlation metrics; and determining a payload using the largest metric of the decoding metrics and at least one of an average metric and the second largest metric of the decoding metrics.Type: ApplicationFiled: February 21, 2007Publication date: January 8, 2009Inventors: Zheng Zi Li, Yong Suk Hwang, Jae Hyeong Kim, Sang Bae Ji