Coherent dual-channel QPSK modulator/demodulator for CDMA systems, and modulating/demodulating methods therefor
US5960029A · kind A · utility
19Cited by
8References
26Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1996 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/362
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.