CDMA frequency acquisition using a simplified crystal oscillator that is not temperature compensated
US8144821B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2006 |
| Grant date | Mar 27, 2012 |
| Priority date | — |
| Expiry date | Dec 27, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7075
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
CDMA code channels are acquired using a crystal oscillator that is not temperature compensated and that generates a tuning signal with relatively large frequency error (e.g., +/−5 ppm). Channel acquisition is first attempted at no offset from a start frequency that is obtained by fitting an ideal temperature/frequency error curve to available actual data points. Following unsuccessful pilot acquisition, the offset frequency is stepped in a “spiral” manner, and pilot acquisition is retried. When the pilot and synchronization channels are successfully acquired, but the system identification is unexpected, an adjacent channel image has been acquired, and the offset frequency is bumped by a large step (e.g., 15 kHz). Pilot acquisition is retried using spiral stepping. The crystal oscillator is calibrated after each successful acquisition of the pilot, synchronization and paging channels by retaining a data point in a frequency adjustment table for the temperature at which frequency acquisition was successful.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.