Patents by Inventor Dong Joon Choi

Dong Joon Choi 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).

  • Patent number: 10110275
    Abstract: A method of estimating an integer frequency offset and compensating for the integer frequency offset by an estimated error is provided. A frequency offset estimation method may include receiving a reception signal including PLC data and a physical layer link channel (PLC) preamble, detecting first position information on a position of a subcarrier of the PLC preamble in a frequency axis from the reception signal through a cross-correlation between the PLC preamble and the reception signal, detecting second position information on the position of the subcarrier of the PLC preamble defined in a transmission end by restoring the PLC data, and calculating a frequency offset by comparing the first position information with the second position information.
    Type: Grant
    Filed: July 21, 2017
    Date of Patent: October 23, 2018
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Jae Hwui Bae, Sang-Jung Ra, Jin Hyuk Song, Joon Young Jung, Dong Joon Choi, Namho Hur
  • Publication number: 20180287823
    Abstract: Disclosed are a roll-off period detection method, a symbol starting point detection method, a fractional frequency offset estimating method, and an OFDM downstream system using the same. A method of detecting a roll-off period in an OFDM downstream system according to an embodiment of the present disclosure may include: generating a temporary roll-off period by applying a windowing function to a signal having a preset length; and detecting a roll-off period based on any one of a cross correlation and a sum of differences between a detection target signal included in a range of two OFDM symbol signals based on a detection starting point, and the temporary roll-off period.
    Type: Application
    Filed: January 8, 2018
    Publication date: October 4, 2018
    Applicant: Electronics and Telecommunications Research Institute
    Inventors: Jae Hwui BAE, Jin Hyuk SONG, Je Won LEE, Joon Young JUNG, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20180167902
    Abstract: Disclosed herein are an apparatus and method for detecting an upstream RF signal based on a preamble. The apparatus for detecting an upstream RF signal based on a preamble includes an analog-to-digital converter unit for receiving an RF analog signal and converting the same into an RF digital signal; a down-converter unit for converting the RF digital signal into a baseband digital signal; a packet detection unit for performing packet detection by performing an operation on the baseband digital signal and preset differential preamble signals; and a timing calculation unit for generating timing information of a terminal device based on the baseband digital signal and time information generated through the packet detection.
    Type: Application
    Filed: November 21, 2017
    Publication date: June 14, 2018
    Inventors: Sang-Jung Ra, Jin-Hyuk Song, Ho-Sook Lee, Dong-Joon Choi, Joon-Young Jung, Nam-Ho Hur
  • Publication number: 20180145843
    Abstract: Disclosed herein is a synchronization method for transmitting a DOCSIS upstream signal, which is performed by an RoIP terminal, the synchronization method including receiving a synchronization (SYNC) message periodically sent by a Cable Modem Termination System (CMTS) and thereby synchronizing a clock and generating a reference time; receiving a ranging request signal from a Cable Modem (CM); including information about a start time of an allocated ranging interval in the ranging request signal, converting the ranging request signal into an IP packet, and transmitting the IP packet to an RoIP headend device over an IP network in order to enable the RoIP headend device to convert the ranging request signal, delivered via the IP network, into an RF signal and transmit the RF signal to the CMTS; and converting a ranging response message delivered from the CMTS into an electric signal and transmitting the electric signal to the CM.
    Type: Application
    Filed: October 25, 2017
    Publication date: May 24, 2018
    Applicant: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Dong-Joon CHOI, Joon-Young JUNG, Nam-Ho HUR
  • Publication number: 20180102808
    Abstract: A method of estimating an integer frequency offset and compensating for the integer frequency offset by an estimated error is provided. A frequency offset estimation method may include receiving a reception signal including PLC data and a physical layer link channel (PLC) preamble, detecting first position information on a position of a subcarrier of the PLC preamble in a frequency axis from the reception signal through a cross-correlation between the PLC preamble and the reception signal, detecting second position information on the position of the subcarrier of the PLC preamble defined in a transmission end by restoring the PLC data, and calculating a frequency offset by comparing the first position information with the second position information.
    Type: Application
    Filed: July 21, 2017
    Publication date: April 12, 2018
    Inventors: Jae Hwui BAE, Sang-Jung RA, Jin Hyuk SONG, Joon Young JUNG, Dong Joon CHOI, Namho HUR
  • Patent number: 9832065
    Abstract: Disclosed are an apparatus and a method for soft-decision demodulating in non-square quadrature amplitude modulation. The apparatus includes: a signal receiving unit receiving a quadrature amplitude modulation (QAM) modulated signal at an m modulation degree at a transmitting side; a soft-decision bit calculating unit determining a soft-decision bit value by calculating log likelihood ratios (LLRs) for m bits of the received QAM modulated signal; and a signal decoding unit restoring the received QAM modulated signal based on the determined soft-decision bit value, in which the soft-decision bit calculating unit defines a log likelihood ratio calculation equation by approximating soft-decision boundary points of constellation points for m bits of non-square QAM having odd bits, respectively.
    Type: Grant
    Filed: May 11, 2016
    Date of Patent: November 28, 2017
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Joon Young Jung, Je Won Lee, Dong Joon Choi, Nam Ho Hur
  • Publication number: 20170324541
    Abstract: Disclosed are a method for acquiring synchronization in a cable network, and a physical (PHY) transmitter and PHY receiver. The method for acquiring synchronization in a cable network according to an embodiment includes receiving, by a PHY receiver, a signal from a PHY transmitter, and acquiring, by the PHY receiver, channel synchronization when a symbol in which a channel preamble exists is detected from the received signal and a position of a frequency in which a channel subcarrier exists is detected from the detected symbol by performing a cross correlation operation on the received signal and the channel preamble.
    Type: Application
    Filed: February 24, 2017
    Publication date: November 9, 2017
    Applicant: Electronics and Telecommunications Research Institute
    Inventors: Jae Hwui BAE, Sang Jung RA, Jin Hyuk SONG, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20170279648
    Abstract: Disclosed is a an apparatus for reducing a reducing a peak to average power ratio (PAPR) for layer division multiplexing (LDM) in an orthogonal frequency division multiplexing (OFDM) system, the apparatus may include a peak remover configured to detect a peak power value of a subcarrier signal that is input and generate a peak removal signal that decreases the detected peak power value, and a processor configured to perform constellation remapping on a first signal generated by combining the subcarrier signal and the peak removal signal and then generate a second signal into which additional data is inserted.
    Type: Application
    Filed: January 11, 2017
    Publication date: September 28, 2017
    Inventors: Jin Hyuk SONG, Sang Jung RA, Jae Hwui BAE, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20170257468
    Abstract: An apparatus and method for transmitting moving picture experts group (MPEG)-2 transport stream (TS) broadcasting data for a broadcasting service based on a physical layer transmission standard defined in a Data over Cable Service Interface Specification (DOCSIS) 3.1. The apparatus includes a converter configured to receive an input of broadcasting data including a plurality of MPEG-2 TS packets and to convert the broadcasting data to a first file with a forward error correction (FEC) codeword structure, and an encoder configured to encode the first file.
    Type: Application
    Filed: January 11, 2017
    Publication date: September 7, 2017
    Inventors: Joon Young JUNG, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20170180049
    Abstract: Provided are an apparatus and method for broadcasting-communications convergence in a hybrid fiber coax (HFC) network. The apparatus includes an optical connector configured to receive broadcast data and communication data from a cable broadcasting station through an optical cable, a channel switch configured to receive the broadcast data from the optical connector and select a piece of broadcast data to be transmitted to a subscriber from among pieces of the broadcast data, and a convergence processor configured to receive the communication data from the optical io connector, receive the selected piece of broadcast data from the channel switch, generate broadcasting-communications convergence data by multiplexing the received communication data and the selected piece of broadcast data, and transmit the broadcasting-communications convergence data.
    Type: Application
    Filed: September 23, 2016
    Publication date: June 22, 2017
    Inventors: Tae Kyoon KIM, Joon Young JUNG, Dong Joon CHOI, Yong Seong CHO, Nam Ho HUR
  • Publication number: 20170048094
    Abstract: An apparatus and a method of channel estimation and equalization based on pilot signals, which acquire a channel estimation vector and effectively perform channel equalization by using scattered pilots and continuous pilots in a communication system to which an OFDM symbol is applied, such as a DOCSIS 3.1 Down stream PHY system using multiple carriers.
    Type: Application
    Filed: July 15, 2016
    Publication date: February 16, 2017
    Inventors: Jae Hwui BAE, Sang Jung RA, Jae Ho LEE, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20160337081
    Abstract: Disclosed are an apparatus and a method for soft-decision demodulating in non-square quadrature amplitude modulation. The apparatus includes: a signal receiving unit receiving a quadrature amplitude modulation (QAM) modulated signal at an m modulation degree at a transmitting side; a soft-decision bit calculating unit determining a soft-decision bit value by calculating log likelihood ratios (LLRs) for m bits of the received QAM modulated signal; and a signal decoding unit restoring the received QAM modulated signal based on the determined soft-decision bit value, in which the soft-decision bit calculating unit defines a log likelihood ratio calculation equation by approximating soft-decision boundary points of constellation points for m bits of non-square QAM having odd bits, respectively.
    Type: Application
    Filed: May 11, 2016
    Publication date: November 17, 2016
    Inventors: Joon Young JUNG, Je Won LEE, Dong Joon CHOI, Nam Ho HUR
  • Publication number: 20160164664
    Abstract: An apparatus and a method for converting an upstream radio frequency (RF) signal to a digital signal and transmitting the digital signal via an Internet protocol (IP) packet based on an optical network in a cable broadcasting network is provided. The apparatus for transmitting an upstream RF signal includes a detector configured to detect an upstream RF signal, and a transmitter configured to digitize the detected upstream RF signal and transmit the digitized RF signal to a headend via an IP packet.
    Type: Application
    Filed: December 4, 2015
    Publication date: June 9, 2016
    Inventors: Joon Young JUNG, Jae Ho LEE, Dong Joon CHOI, Nam Ho HUR
  • Patent number: 9271017
    Abstract: A broadcasting transmitting apparatus configures one broadcasting channel as at least two video streams, generates a program map table (PMT) representing configuration information of a stream included within the broadcasting channel, sets a program type provided through the corresponding broadcasting channel within the PMT, multiplexes the at least two video streams and signaling information, and transmits the multiplexed two video streams and signaling information through a broadcasting network.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: February 23, 2016
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Joon Young Jung, Dong Joon Choi, Namho Hur
  • Publication number: 20160037534
    Abstract: Provided is a channel switching method and channel reception method to enhance spectrum use efficiency and a channel switching apparatus and channel reception apparatus using the same. The channel switching method may include extracting, based on received information associated with a virtual channel currently viewed by a user, broadcasting data on a corresponding virtual channel in a physical channel, determining communication data to be added to an idle frequency band in the physical channel including the extracted broadcasting data, and transmitting a transmission data stream generated based on communication data and broadcasting data included in the physical channel, wherein the physical channel comprises broadcasting data on a plurality of virtual channels and uses a predetermined frequency band.
    Type: Application
    Filed: July 28, 2015
    Publication date: February 4, 2016
    Inventors: Joon Young JUNG, Dong Joon CHOI, Nam Ho HUR
  • Patent number: 9232029
    Abstract: A demultiplexing apparatus, a multiplexing apparatus, and a multi-channel transmission and reception method using the same are provided. The demultiplexing apparatus includes a broadcasting data reception unit for separating a broadcasting data stream into N input packets, an output packet generation unit for generating (N+1) output packets by connecting a pre-header, including a field for multi-channel transmission, with each of the N input packets, and a packet distribution unit for distributing the (N+1) output packets over at least two channels.
    Type: Grant
    Filed: November 20, 2013
    Date of Patent: January 5, 2016
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Joon Young Jung, Dong Joon Choi, Nam Ho Hur
  • Patent number: 9167309
    Abstract: A method for transmitting broadcast and data streams in an HFC-based cable network includes a first transmission step of a broadcast transmission apparatus sending broadcast and data service streams in an IP-based stream or RF signal form through an optical section up to a cell node that is a contact point between the optical section and a cable section of a cable network and a second transmission step of the cell node converting the broadcast and data service streams into one of RF signal, IP-based stream, and RF/IP convergence service stream forms depending on a service type of a subscriber terminal and sending the converted broadcast and data service streams to the subscriber terminal through the cable section.
    Type: Grant
    Filed: August 1, 2013
    Date of Patent: October 20, 2015
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Ho Sook Lee, Dong Joon Choi, Nam Ho Hur
  • Patent number: 9154293
    Abstract: Disclosed are a method and apparatus for estimating symbol timing in a non-synchronized OFDM system. The present invention includes synchronizing a frame of a received signal, estimating the symbol timing of each symbol of the frame based on the synchronization, compensating for the symbol timing using a phase difference attributable to a Symbol Timing Offset (STO), variably changing within a Cyclic Prefix (CP) interval due to the frequency offset of a sampling clock and thermal noise, and performing channel equalization using a preamble based on output including corrected phase rotation.
    Type: Grant
    Filed: December 5, 2013
    Date of Patent: October 6, 2015
    Assignee: ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE
    Inventors: Jae Ho Lee, Yang Su Kim, Sang Jung Ra, Han Seung Koo, Dong Joon Choi, Nam Ho Hur
  • Publication number: 20150256982
    Abstract: A method and apparatus for providing a mobile broadcasting service over a cable broadcasting network are provided. A mobile broadcast signal and a cable broadcast signal are transmitted over the cable broadcast network. The cable broadcast signal and the mobile broadcast signal are filtered to pass the mobile broadcast signal, and the passed mobile broadcast signal is sent to a mobile broadcast terminal.
    Type: Application
    Filed: February 26, 2015
    Publication date: September 10, 2015
    Inventors: Joon Young JUNG, Dong Joon CHOI, Namho HUR, YONG SEONG CHO
  • Patent number: 9059886
    Abstract: In an orthogonal frequency division multiplexing (OFDM) wireless communication system, when path delay information is received from a reception apparatus through a return path after data transmission, a length of a cyclic prefix included in a transmitted signal is adjusted on the basis of a delay value included in the path delay information.
    Type: Grant
    Filed: June 19, 2014
    Date of Patent: June 16, 2015
    Assignee: Electronics and Telecommunications Research Institute
    Inventors: Jae-Ho Lee, Sang-Jung Ra, Dong Joon Choi, Namho Hur