Spread spectrum communication terminal apparatus in CDMA cellular telephone system
US5699380A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 26, 1995 |
| Grant date | Dec 16, 1997 |
| Priority date | — |
| Expiry date | Sep 26, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J13/0003
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A number of demodulators receive a signal transmitted from a certain base station and propagated via different respective propagation paths. Each demodulator generates a demodulated signal by examining the correlation between the received signal and a pseudo-noise (PN) spread code. A system time managing counter has a count value that is initialized at the timing of the forefront of the spread code in the modulator when at least one of the demodulators starts the demodulating process after power-on or after a reset operation. A signal combiner combines the demodulated signals that are adjusted to coincide in timing with each other from the demodulators at a timing determined by a system time managing counter after initialization and provides a combined demodulated signal. A control circuit reads the information of the time offset of the PN code to the system time from the sync channel message on a sync channel in the synthetic demodulated signal, so that the system time of the base station is set to the system time managing counter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.