Stabilization of frequency and power in an airborne communication system
US5455964A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1993 |
| Grant date | Oct 3, 1995 |
| Priority date | — |
| Expiry date | Mar 26, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04W48/12
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The frequency and power of transmissions in a mobile communication system, such as an air-to-ground telephony system, are stabilized without a priori knowledge of the system gain factors or frequency references. The ground station monitors the available channels and modifies a vacant channel broadcast message to provide information that the channel is available. In this way, the air terminals have knowledge of all available channels. The ground station transmits a pilot signal. Upon request by a user for a dial tone at the air terminal, the air terminal selects a vacant channel and scans for the pilot signal. The air terminal estimates a distance to the ground station and sets a power level of a seizing transmission based on the estimated distance. The air terminal also estimates a Doppler frequency shift of the selected channel due to the relative movement of the air terminal with respect to the ground station and sets a frequency of the seizing transmission based on the estimated Doppler frequency shift. The air terminal then transmits a channel seizing signal at a reduced bandwidth less than a full normal bandwidth to the ground station at the set level and frequency. The ground…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.