Patents by Inventor An Na Choi

An Na 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).

  • Apparatus and method for generating pilot beacon signal in base stations of CDMA system
    Patent number: 7254122
    Abstract: An apparatus for generating pilot beacon signals for handoff between base stations having a different frequency assignment FA in a code division multiple access CDMA radio communication system includes a PN code generating unit for generating inphase (I)-channel and quadrature (Q)-channel pseudo noise (PN) sequences; a pulse shaping unit for shaping an I-channel and Q-channel PN signal by filtering the I-channel and Q-channel PN sequences; an equalizing unit for equalizing phases of the I-channel PN signal and the Q-channel PN signal and generating an equalized I-channel signal and an equalized Q-channel signal; an interpolation filtering unit for converting frequencies of the equalized I-channel signal with the equalized Q-channel signal to intermediate frequencies (IF) and generating an IF I-channel signal and an IF Q-channel signal; a modulation unit for modulating IF I-channel and Q-channel signals and generating a modulated I-channel signal and a modulated Q-channel signal; a combining unit for combining
    Type: Grant
    Filed: May 13, 2003
    Date of Patent: August 7, 2007
    Assignee: SK Telecom Co., Ltd.
    Inventors: An Na Choi, Jae Hwang Yu, Jun Mo Koo, Byung Moo Kim
  • Apparatus and method for generating pilot beacon signal in base stations of CDMA system
    Publication number: 20030214926
    Abstract: An apparatus for generating pilot beacon signals for handoff between base stations having a different frequency assignment FA in a code division multiple access CDMA radio communication system includes a PN code generating unit for generating inphase (I)-channel and quadrature (Q)-channel pseudo noise (PN) sequences; a pulse shaping unit for shaping an I-channel PN signal and a Q-channel PN signal by filtering the I-channel and Q-channel PN sequences; an equalizing unit for equalizing phases of the I-channel PN signal and the Q-channel PN signal and generating an equalized I-channel signal and an equalized Q-channel signal; an interpolation filtering unit for converting frequencies of the equalized I-channel signal with the equalized Q-channel signal to intermediate frequencies (IF) and generating an IF I-channel signal and an IF Q-channel signal; a modulation unit for modulating IF I-channel and Q-channel signals and generating a modulated I-channel signal and a modulated Q-channel signal; combining unit for
    Type: Application
    Filed: May 13, 2003
    Publication date: November 20, 2003
    Inventors: An Na Choi, Jae Hwang Yu, Jun Mo Koo, Byung Moo Kim
  • Method for accessing a cell using two pilot channels in a CDMA communication system of an asynchronous or quasi-synchronous mode
    Patent number: 6205132
    Abstract: The present invention discloses a method for accessing a cell, and more particularly, to a method for acquiring an initial synchronization using two pilot channels in a CDMA (Code Division Multiple Access) communication system of an asynchronous or quasi-synchronous mode. In accordance with the present invention, a CDMA communication system of an quasi-synchronous mode comprises the steps of synchronizing the mobile station with a cluster pilot, and searching for cell pilots on the basis of the cluster synchronization channel set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity, whereby the mobile station is synchronized with the base station through the cluster pilot and the cell pilot.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: March 20, 2001
    Assignee: Korea Mobile Telecommunications Corp.
    Inventors: Een Kee Hong, Dong Ho Kim, Yeon Dae Yang, Byeong Chul Ahn, Yong Wan Park, Seong Moon Ryu, Tae Young Lee, An Na Choi