Multiple vocoder mobile satellite telephone system
US6418147B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 21, 1998 |
| Grant date | Jul 9, 2002 |
| Priority date | — |
| Expiry date | Jan 21, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/18532
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A user terminal (16) includes an RF transceiver (30) for transmitting modulated RF signals to a gateway (14) and for receiving modulated RF signals from the gateway via at least one satellite (112). The satellite may be a GEO or a non-GEO satellite. The user terminal further includes a signal processor (32) coupled to the RF transceiver for demodulating received RF signals to digital signals, an audio unit (90,92,94) for transponding speech signals with a user, and a plurality of encoders/decoders (2A,2B) and/or vocoders (82,84,86) between the signal processor and the audio unit for encoding and decoding speech signals passing to and from the audio unit. A first vocoder can be a variable rate vocoder, a second vocoder can be a fixed rate vocoder, where the fixed rate vocoder operates at an average data rate that differs from, e.g., is less than, an average data rate of the variable rate vocoder. The encoder/decoder or vocoder selection is made in the gateway based on one or more criterion such as a presence of an RF signal impairment or RF interference, a predicted and/or actual communications system, a user-selected voice quality, and/or a signal quality received from the user ter…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.