The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1999
Filed:
Sep. 30, 1996
Applicant:
Inventors:
Seong-Rag Kim, Daejeon, KR;
Hun Lee, Daejeon, KR;
Byung-Shik Kang, Daejeon, KR;
Jae-Wook Jung, Daejeon, KR;
Assignee:
Electronics and Telecommunications Research Institute, Daejeon, KR;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ; H04K / ; H04L / ;
U.S. Cl.
CPC ...
375200 ; 375205 ; 375208 ; 375219 ; 370209 ; 370335 ; 370491 ;
Abstract
A coherent dual-channel QPSK modulator/demodulator for a CDMA system, and modulating/demodulating methods therefor, are disclosed, in which the crosstalk interferences between an I-channel and a Q-channel are eliminated by an orthogonal spreading method, which assigns different Walsh codes to the I-channel and Q-channel. Pseudo-random modulation and pseudo-random demodulation are carried out by using one PN code so as to minimize the channel parameter estimation errors, thereby improving receiving performance.